21072G.Book | Datasheet Lookup

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2004 Microchip Technology Inc.

DS21072G-page 1

FEATURES

• Voltage operating range: 2.5V to 6.0V

- Peak write current 3 mA at 6.0V
- Maximum read current 150

A at 6.0V

- Standby current 1

A typical

• Industry standard two-wire bus protocol, I



compatible
- Including 100 kHz (2.5V) and 400 kHz (5V) modes

• Self-timed ERASE and WRITE cycles
• Power on/off data protection circuitry
• Endurance:

- 10,000,000 Erase/Write cycles

guaranteed for High Endurance Block

- 1,000,000 E/W cycles guaranteed for

Standard Endurance Block

• 8 byte page, or byte modes available
• 1 page x 8 line input cache (64 bytes) for fast write

loads

• Schmitt trigger, filtered inputs for noise suppression
• Output slope control to eliminate ground bounce
• 2 ms typical write cycle time, byte or page
• Factory programming (QTP) available
• Up to 8 devices may be connected to the same

bus for up to 256K bits total memory

• Electrostatic discharge protection > 4000V
• Data retention > 200 years
• 8-pin PDIP/SOIC packages
• Temperature ranges

DESCRIPTION

The Microchip Technology Inc. 24LC32 is a 4K x 8
(32K bit) Serial Electrically Erasable PROM capable of
operation across a broad voltage range (2.5V to 6.0V).
This device has been developed for advanced, low
power applications such as personal communications
or data acquisition. The 24LC32 features an input
cache for fast write loads with a capacity of eight 8-byte
pages, or 64 bytes. It also features a fixed 4K-bit block
of ultra-high endurance memory for data that changes
frequently. The 24LC32 is capable of both random and
sequential reads up to the 32K boundary. Functional
address lines allow up to eight 24LC32 devices on the
same bus, for up to 256K bits address space.
Advanced CMOS technology and broad voltage range
make this device ideal for low-power/low voltage, non-
volatile code and data applications. The 24LC32 is
available the standard 8-pin in plastic DIP and 8-pin
surface mount SOIC package.

- Commercial (C):

0°C to +70°C

- Industrial (I):

-40° to

+85°

PACKAGE TYPES

BLOCK DIAGRAM

24L

SCL

SDA

24L

C32

SCL

SDA

PDIP

SOIC

HV GENERATOR

EEPROM

ARRAY

PAGE LATCHES

YDEC

XDEC

SENSE AMP

MEMORY

CONTROL

LOGIC

I/O

CONTROL

LOGIC

SDA

SCL

I/O

CACHE

R/W CONTROL

24LC32

32K 2.5V I

™

Smart Serial EEPROM

C is a trademark of Philips Corporation. Smart Serial is a trademark of Microchip Technology Inc.

Obsolete Device

Please use 24LC32A or 24LC65.

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24LC32

DS21072G-page 2

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2004 Microchip Technology Inc.

1.0

ELECTRICAL
CHARACTERISTICS

1.1

Maximum Ratings*

..................................................................................7.0V

All inputs and outputs w.r.t. V

............... -0.6V to V

+1.0V

Storage temperature .....................................-65°C to +150°C
Ambient temp. with power applied ................-65°C to +125°C
Soldering temperature of leads (10 seconds) ............. +300°C
ESD protection on all pins

..................................................≥

4 kV

*Notice: Stresses above those listed under “Maximum Ratings”
may cause permanent damage to the device. This is a stress rat-
ing only and functional operation of the device at those or any
other conditions above those indicated in the operational listings
of this specification is not implied. Exposure to maximum rating
conditions for extended periods may affect device reliability.

TABLE 1-1:

PIN FUNCTION TABLE

Name

Function

A0,A1,A2

User Configurable Chip Selects

Ground

SDA

Serial Address/Data I/O

SCL

Serial Clock

+2.5V to 6.0V Power Supply

No Internal Connection

TABLE 1-2:

DC CHARACTERISTICS

FIGURE 1-1:

BUS TIMING START/STOP

= +2.5V to 6.0V

Commercial (C):

Tamb

= 0°C to +70°C

Industrial (I):

Tamb

= -40°C to +85°C

Parameter

Symbol

Min

Max

Units

Conditions

A0, A1, A2, SCL and SDA pins:

High level input voltage

.7 V

—

Low level input voltage

—

.3 Vcc

Hysteresis of Schmitt Trigger inputs

HYS

.05 V

—

(Note)

Low level output voltage

—

.40

= 3.0 mA

Input leakage current

-10

= .1V to V

Output leakage current

-10

OUT

= .1V to V

Pin capacitance
(all inputs/outputs)

OUT

—

= 5.0V (Note)

Tamb = 25°C, Fclk = 1 MHz

Operating current

Write

Read

—
—

150

= 6.0V, SCL = 400 kHz

Standby current

CCS

—

= 5.0V, SCL = SDA = V

A0, A1, A2 = V

Note:

This parameter is periodically sampled and not 100% tested.

STA

HYS

STO

START

STOP

SCL

SDA

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2004 Microchip Technology Inc.

DS21072G-page 3

24LC32

TABLE 1-3:

AC CHARACTERISTICS

FIGURE 1-2:

BUS TIMING DATA

Parameter

Symbol

= 2.5V-6.0V

STD. MODE

= 4.5 - 6.0V

FAST MODE

Units

Remarks

Min

Max

Min

Max

Clock frequency

CLK

—

100

—

400

kHz

Clock high time

HIGH

4000

—

600

—

Clock low time

LOW

4700

—

1300

—

SDA and SCL rise time

—

1000

—

300

(Note1)

SDA and SCL fall time

—

300

—

300

(Note1)

START condition hold time

STA

4000

—

600

—

After this period the first clock
pulse is generated

START condition setup time

STA

4700

—

600

—

Only relevant for repeated
START condition

Data input hold time

DAT

—

Data input setup time

DAT

250

—

100

—

STOP condition setup time

STO

4000

—

600

—

Output valid from clock

—

3500

—

900

(Note 2)

Bus free time

BUF

4700

—

1300

—

Time the bus must be free
before a new transmission can
start

Output fall time from V

min

to V

max

—

250

20 +0.1

250

(Note 1), C

≤

100 pF

Input filter spike suppression
(SDA and SCL pins)

—

(Note 3)

Write cycle time

—

ms/page (Note 4)

Endurance

High Endurance Block
Rest of Array

—
—

10M

—
—

10M

—
—

cycles

25°C, Vcc = 5.0V, Block Mode
(Note 5)

Note 1: Not 100% tested. C

= total capacitance of one bus line in pF.

2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region

(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of START or STOP conditions.

3: The combined T

and V

HYS

specifications are due to new Schmitt trigger inputs which provide improved

noise and spike suppression. This eliminates the need for a Ti specification for standard operation.

4: The times shown are for a single page of 8 bytes. Multiply by the number of pages loaded into the write

cache for total time.

5: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-

cation, please consult the Total Endurance Model which can be obtained from our website.

SCL

SDA
IN

SDA
OUT

STA

LOW

HIGH

STA

DAT

STO

BUF

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24LC32

DS21072G-page 4

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2004 Microchip Technology Inc.

2.0

FUNCTIONAL DESCRIPTION

The 24LC32 supports a bidirectional two-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as transmitter, and a device
receiving data as receiver. The bus must be controlled
by a master device which generates the serial clock
(SCL), controls the bus access, and generates the
START and STOP conditions, while the 24LC32 works
as slave. Both master and slave can operate as trans-
mitter or receiver but the master device determines
which mode is activated.

3.0

BUS CHARACTERISTICS

The following bus protocol has been defined:

• Data transfer may be initiated only when the bus

is not busy.

• During data transfer, the data line must remain

stable whenever the clock line is HIGH. Changes
in the data line while the clock line is HIGH will be
interpreted as a START or STOP condition.

Accordingly, the following bus conditions have been
defined (Figure 3-1).

3.1

Bus not Busy (A)

Both data and clock lines remain HIGH.

3.2

Start Data Transfer (B)

A HIGH to LOW transition of the SDA line while the
clock (SCL) is HIGH determines a START condition.
All commands must be preceded by a START condi-
tion.

3.3

Stop Data Transfer (C)

A LOW to HIGH transition of the SDA line while the
clock (SCL) is HIGH determines a STOP condition. All
operations must be ended with a STOP condition.

3.4

Data Valid (D)

The state of the data line represents valid data when,
after a START condition, the data line is stable for the
duration of the HIGH period of the clock signal.

The data on the line must be changed during the LOW
period of the clock signal. There is one clock pulse per
bit of data.

Each data transfer is initiated with a START condition
and terminated with a STOP condition. The number of
the data bytes transferred between the START and
STOP conditions is determined by the master device.

3.5

Acknowledge

Each receiving device, when addressed, is obliged to
generate an acknowledge signal after the reception of
each byte. The master device must generate an extra
clock pulse which is associated with this acknowledge
bit.

A device that acknowledges  must pull down the SDA
line during the acknowledge clock pulse in such a way
that the SDA line is stable LOW during the HIGH period
of the acknowledge related clock pulse.   Of course,
setup and hold times must be taken into account.  Dur-
ing reads, a master must signal an end of data to the
slave by NOT generating an acknowledge bit on the
last byte that has been clocked out of the slave.  In this
case, the slave (24LC32) will leave the data line HIGH
to enable the master to generate the STOP condition.

Note:

The 24LC32 does not generate any
acknowledge bits if an internal program-
ming cycle is in progress.

FIGURE 3-1:

DATA TRANSFER SEQUENCE ON THE SERIAL BUS

SCL

SDA

(A)

(B)

(D)

(A)

(C)

START

CONDITION

ADDRESS OR

ACKNOWLEDGE

VALID

DATA

ALLOWED

TO CHANGE

STOP

CONDITION

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2004 Microchip Technology Inc.

DS21072G-page 5

24LC32

3.6

Device Addressing

A control byte is the first byte received following the
start condition from the master device. The control byte
consists of a four bit control code; for the 24LC32 this
is set as 1010 binary for read and write operations. The
next three bits of the control byte are the device select
bits (A2, A1, A0). They are used by the master device
to select which of the eight devices are to be accessed.
These bits are in effect the three most significant bits of
the word address. The last bit of the control byte
defines the operation to be performed. When set to a
one a read operation is selected, and when set to a
zero a write operation is selected. The next two bytes
received define the address of the first data byte
(Figure 3-3). Because only A11...A0 are used, the
upper four address bits must be zeros. The most signif-
icant bit of the most significant byte of the address is
transferred first.

Following the start condition, the 24LC32 monitors the
SDA bus checking the device type identifier being
transmitted. Upon receiving a 1010 code and appropri-
ate device select bits, the slave device outputs an
acknowledge signal on the SDA line. Depending on
the state of the R/W bit, the 24LC32 will select a read
or write operation.

FIGURE 3-2:

CONTROL BYTE
ALLOCATION

Operation

Control

Code

Device Select

R/W

Read

1010

Device Address

Write

1010

Device Address

SLAVE ADDRESS

R/W

START

READ/WRITE

FIGURE 3-3:

ADDRESS SEQUENCE BIT ASSIGNMENTS

0 R/W

•

SLAVE

ADDRESS

DEVICE

SELECT

BUS

CONTROL BYTE

ADDRESS BYTE 1

ADDRESS BYTE 0

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24LC32

DS21072G-page 6

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2004 Microchip Technology Inc.

4.0

WRITE OPERATION

4.1

Split Endurance

The 24LC32 is organized as a continuous 32K block of
memory. However, the first 4K, starting at address 000,
is rated at 10,000,000 E/W cycles guaranteed. The
remainder of the array, 28K bits, is rated at 100,000 E/
W cycles guaranteed. This feature is helpful in applica-
tions in which some data change frequently, while a
majority of the data change infrequently. One example
would be a cellular telephone in which last-number
redial and microcontroller scratch pad require a high-
endurance block, while speed dials and lookup tables
change infrequently and so require only a standard
endurance rating.

4.2

Byte Write

Following the start condition from the master, the con-
trol code (four bits), the device select (three bits), and
the R/W bit which is a logic low are clocked onto the
bus by the master transmitter. This indicates to the
addressed slave receiver that a byte with a word
address will follow after it has generated an acknowl-
edge bit during the ninth clock cycle. Therefore the
next byte transmitted by the master is the high-order
byte of the word address and will be written into the
address pointer of the 24LC32. The next byte is the
least significant address byte. After receiving another
acknowledge signal from the 24LC32 the master
device will transmit the data word to be written into the
addressed memory location.

The 24LC32 acknowledges again and the master gen-
erates a stop condition. This initiates the internal write
cycle, and during this time the 24LC32 will not generate
acknowledge signals (Figure 4-1).

4.3

Page Write

The write control byte, word address and the first data
byte are transmitted to the 24LC32 in the same way as
in a byte write. But instead of generating a stop condi-
tion, the master transmits up to eight pages of eight
data bytes each (64 bytes total) which are temporarily
stored in the on-chip page cache of the 24LC32. They
will be written from cache into the EEPROM array after
the master has transmitted a stop condition. After the
receipt of each word, the six lower order address
pointer bits are internally incremented by one. The
higher order seven bits of the word address remain
constant. If the master should transmit more than eight
bytes prior to generating the stop condition (writing
across a page boundary), the address counter (lower
three bits) will roll over and the pointer will be incre-
mented to point to the next line in the cache. This can
continue to occur up to eight times or until the cache is
full, at which time a stop condition should be generated
by the master. If a stop condition is not received, the
cache pointer will roll over to the first line (byte 0) of the
cache, and any further data received will overwrite pre-
viously captured data. The stop condition can be sent
at any time during the transfer. As with the byte write
operation, once a stop condition is received, an internal
write cycle will begin. The 64-byte cache will continue
to capture data until a stop condition occurs or the oper-
ation is aborted (Figure 4-2).

FIGURE 4-1:

BYTE WRITE

FIGURE 4-2:

PAGE WRITE (FOR CACHE WRITE, SEE FIGURE 7-1)

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (0)

DATA

A
C
K

S
T
O
P

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (2)

DATA n

A
C
K

S
T
O
P

DATA n + 7

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2004 Microchip Technology Inc.

DS21072G-page 7

24LC32

5.0

ACKNOWLEDGE POLLING

Since the device will not acknowledge during a write
cycle, this can be used to determine when the cycle is
complete (this feature can be used to maximize bus
throughput). Once the stop condition for a write com-
mand has been issued from the master, the device ini-
tiates the internally timed write cycle. ACK polling can
be initiated immediately. This involves the master send-
ing a start condition followed by the control byte for a
write command (R/W = 0). If the device is still busy with
the write cycle, then no ACK will be returned. If the
cycle is complete, then the device will return the ACK
and the master can then proceed with the next read or
write command. See Figure 5-1 for flow diagram.

FIGURE 5-1:

ACKNOWLEDGE POLLING
FLOW

Send

Write Command

Send Stop

Condition to

Initiate Write Cycle

Send Start

Send Control Byte

with R/W = 0

Did Device

Acknowledge

(ACK = 0)?

Operation

YES

6.0

READ OPERATION

Read operations are initiated in the same way as write
operations with the exception that the R/W bit of the
slave address is set to one. There are three basic
types of read operations: current address read, random
read, and sequential read.

6.1

Current Address Read

The 24LC32 contains an address counter that main-
tains the address of the last word accessed, internally
incremented by one. Therefore, if the previous access
(either a read or write operation) was to address n (n is
any legal address), the next current address read oper-
ation would access data from address n + 1. Upon
receipt of the slave address with R/W bit set to one, the
24LC32 issues an acknowledge and transmits the eight
bit data word. The master will not acknowledge the
transfer but does generate a stop condition and the
24LC32 discontinues transmission (Figure 6-1).

6.2

Random Read

Random read operations allow the master to access
any memory location in a random manner. To perform
this type of read operation, first the word address must
be set. This is done by sending the word address to the
24LC32 as part of a write operation (R/W bit set to 0).
After the word address is sent, the master generates a
start condition following the acknowledge. This termi-
nates the write operation, but not before the internal
address pointer is set. Then the master issues the con-
trol byte again but with the R/W bit set to a one. The
24LC32 will then issue an acknowledge and transmit
the eight bit data word. The master will not acknowl-
edge the transfer but does generate a stop condition
which causes the 24LC32 to discontinue transmission
(Figure 6-2).

FIGURE 6-1:

CURRENT ADDRESS READ

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

S
T
O
P

CONTROL

BYTE

DATA n

A
C
K

N
O

A
C
K

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24LC32

DS21072G-page 8

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2004 Microchip Technology Inc.

6.3

Contiguous Addressing Across
Multiple Devices

The device select bits A2, A1, A0 can be used to
expand the contiguous address space for up to 256K
bits by adding up to eight 24LC32's on the same bus.
In this case, software can use A0 of the control byte as
address bit A12, A1 as address bit A13, and A2 as
address bit A14.

6.4

Sequential Read

Sequential reads are initiated in the same way as a ran-
dom read except that after the 24LC32 transmits the
first data byte, the master issues an acknowledge as
opposed to the stop condition used in a random read.
This acknowledge directs the 24LC32 to transmit the
next sequentially addressed 8 bit word (Figure 6-3).
Following the final byte transmitted to the master, the
master will NOT generate an acknowledge but will gen-
erate a stop condition.

To provide sequential reads the 24LC32 contains an
internal address pointer which is incremented by one at
the completion of each operation. This address pointer
allows the entire memory contents to be serially read
during one operation. The address pointer, however,
will not roll over from address 07FF to address 0000. It
will roll from 07FF to unused memory space.

6.5

Noise Protection

The SCL and SDA inputs have filter circuits which sup-
press noise spikes to ensure proper device operation
even on a noisy bus. All I/O lines incorporate Schmitt
triggers for 400 kHz (Fast Mode) compatibility.

FIGURE 6-2:

RANDOM READ

FIGURE 6-3:

SEQUENTIAL READ

SDA LINE

BUS

CONTROL

BYTE

WORD

ADDRESS (1)

S
T

S
T
A

A
C
K

ACTIVITY:

N
O

DATA n

0 0 0

WORD

ADDRESS (0)

A
R

CONTROL

BYTE

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
O
P

CONTROL

BYTE

A
C
K

N
O

DATA n

DATA n + 1

DATA n + 2

DATA n + X

A
C
K

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2004 Microchip Technology Inc.

DS21072G-page 9

24LC32

6.6

PAGE CACHE AND ARRAY MAPPING

The cache is a 64 byte (8 pages x 8 bytes) FIFO buffer.
The cache allows the loading of up to 64 bytes of data
before the write cycle is actually begun, effectively pro-
viding a 64-byte burst write at the maximum bus rate.
Whenever a write command is initiated, the cache
starts loading and will continue to load until a stop bit is
received to start the internal write cycle. The total
length of the write cycle will depend on how many
pages are loaded into the cache before the stop bit is
given. Maximum cycle time for each page is 5 ms. Even
if a page is only partially loaded, it will still require the
same cycle time as a full page. If more than 64 bytes of
data are loaded before the stop bit is given, the address
pointer will'wrap around' to the beginning of cache
page 0 and existing bytes in the cache will be overwrit-
ten. The device will not respond to any commands
while the write cycle is in progress.

6.7

Cache Write Starting at a Page
Boundary

If a write command begins at a page boundary
(address bits A2, A1 and A0 are zero), then all data
loaded into the cache will be written to the array in
sequential addresses. This includes writing across a
4K block boundary. In the example shown below,
(Figure 4-2) a write command is initiated starting at
byte 0 of page 3 with a fully loaded cache (64 bytes).
The first byte in the cache is written to byte 0 of page 3
(of the array), with the remaining pages in the cache
written to sequential pages in the array. A write cycle is
executed after each page is written. Since the write
begins at page 3 and 8 pages are loaded into the
cache, the last 3 pages of the cache are written to the
next row in the array.

6.8

Cache Write Starting at a Non-Page
Boundary

When a write command is initiated that does not begin
at a page boundary (i.e., address bits A2, A1 and A0
are not all zero), it is important to note how the data is
loaded into the cache, and how the data in the cache is
written to the array. When a write command begins, the
first byte loaded into the cache is always loaded into
page 0. The byte within page 0 of the cache where the
load begins is determined by the three least significant
address bits (A2, A1, A0) that were sent as part of the
write command. If the write command does not start at
byte 0 of a page and the cache is fully loaded, then the
last byte(s) loaded into the cache will roll around to
page 0 of the cache and fill the remaining empty bytes.
If more than 64 bytes of data are loaded into the cache,
data already loaded will be overwritten. In the example
shown in Figure 7-2, a write command has been initi-
ated starting at byte 2 of page 3 in the array with a fully
loaded cache of 64 bytes. Since the cache started load-
ing at byte 2, the last two bytes loaded into the cache
will'roll over' and be loaded into the first two bytes of
page 0 (of the cache). When the stop bit is sent, page
0 of the cache is written to page 3 of the array. The
remaining pages in the cache are then loaded sequen-
tially to the array. A write cycle is executed after each
page is written. If a partially loaded page in the cache
remains when the STOP bit is sent, only the bytes that
have been loaded will be written to the array.

6.9

Power Management

This design incorporates a power standby mode when
the device is not in use and automatically powers off
after the normal termination of any operation when a
stop bit is received and all internal functions are com-
plete. This includes any error conditions, ie. not receiv-
ing an acknowledge or stop condition per the two-wire
bus specification. The device also incorporates V

monitor circuitry to prevent inadvertent writes (data cor-
ruption) during low-voltage conditions. The V

moni-

tor circuitry is powered off when the device is in standby
mode in order to further reduce power consumption.

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24LC32

DS21072G-page 10

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2004 Microchip Technology Inc.

7.0

PIN DESCRIPTIONS

7.1

A0, A1, A2 Chip Address Inputs

The A0..A2 inputs are used by the 24LC32 for multiple
device operation and conform to the two-wire bus stan-
dard. The levels applied to these pins define the
address block occupied by the device in the address
map. A particular device is selected by transmitting the
corresponding bits (A2, A1, A0) in the control byte
(Figure 3-3).

7.2

SDA Serial Address/Data Input/Output

This is a bidirectional pin used to transfer addresses
and data into and data out of the device. It is an open
drain terminal, therefore the SDA bus requires a pullup
resistor to V

(typical 10K

Ω

for 100 kHz, 2 K

Ω

for

400 kHz)

For normal data transfer SDA is allowed to change only
during SCL low. Changes during SCL high are
reserved for indicating the START and STOP condi-
tions.

7.3

SCL Serial Clock

This input is used to synchronize the data transfer from
and to the device.

FIGURE 7-1:

CACHE WRITE TO THE ARRAY STARTING AT A PAGE BOUNDARY

FIGURE 7-2:

CACHE WRITE TO THE ARRAY STARTING AT A NON-PAGE BOUNDARY

1 Write command initiated at byte 0 of page 3 in the array;

First data byte is loaded into the cache byte 0.

2 64 bytes of data are loaded into cache.

3 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

4 Remaining pages in cache are written

to sequential pages in array.

cache

byte 0

cache

byte 1

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

byte 7

• • •

page 4

• • •

page 7

page 3

cache page 0

Last page in cache written to page 2 in next row.

array row n

array row n + 1

page 0 page 1 page 2

byte 0

byte 1

page 4

page 7

1 Write command initiated; 64 bytes of data

loaded into cache starting at byte 2 of page 0.

2 Last 2 bytes loaded 'roll over'

to beginning.

Last 2 bytes
loaded into
page 0 of cache.

4 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

cache

byte 1

cache

byte 2

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

page 4

• • •

page 7

page 3

Remaining bytes in cache are
written sequentially to array.

array

row n

array

row

n + 1

cache

byte 0

Last 3 pages in cache written to next row in array.

page 1 page 2

byte 0

byte 2

byte 1

page 4

page 7

byte 7

byte 3

byte 4

page 0

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

2004 Microchip Technology Inc.

DS21072G-page 1

FEATURES

• Voltage operating range: 2.5V to 6.0V

- Peak write current 3 mA at 6.0V
- Maximum read current 150

A at 6.0V

- Standby current 1

A typical

• Industry standard two-wire bus protocol, I



compatible
- Including 100 kHz (2.5V) and 400 kHz (5V) modes

• Self-timed ERASE and WRITE cycles
• Power on/off data protection circuitry
• Endurance:

- 10,000,000 Erase/Write cycles

guaranteed for High Endurance Block

- 1,000,000 E/W cycles guaranteed for

Standard Endurance Block

• 8 byte page, or byte modes available
• 1 page x 8 line input cache (64 bytes) for fast write

loads

bus for up to 256K bits total memory

• Electrostatic discharge protection > 4000V
• Data retention > 200 years
• 8-pin PDIP/SOIC packages
• Temperature ranges

DESCRIPTION

- Commercial (C):

0°C to +70°C

- Industrial (I):

-40° to

+85°

PACKAGE TYPES

BLOCK DIAGRAM

24L

SCL

SDA

24L

C32

SCL

SDA

PDIP

SOIC

HV GENERATOR

EEPROM

ARRAY

PAGE LATCHES

YDEC

XDEC

SENSE AMP

MEMORY

CONTROL

LOGIC

I/O

CONTROL

LOGIC

SDA

SCL

I/O

CACHE

R/W CONTROL

24LC32

32K 2.5V I

™

Smart Serial EEPROM

C is a trademark of Philips Corporation. Smart Serial is a trademark of Microchip Technology Inc.

Obsolete Device

Please use 24LC32A or 24LC65.

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24LC32

DS21072G-page 2



2004 Microchip Technology Inc.

1.0

ELECTRICAL
CHARACTERISTICS

1.1

Maximum Ratings*

..................................................................................7.0V

All inputs and outputs w.r.t. V

............... -0.6V to V

+1.0V

..................................................≥

4 kV

TABLE 1-1:

PIN FUNCTION TABLE

Name

Function

A0,A1,A2

User Configurable Chip Selects

Ground

SDA

Serial Address/Data I/O

SCL

Serial Clock

+2.5V to 6.0V Power Supply

No Internal Connection

TABLE 1-2:

DC CHARACTERISTICS

FIGURE 1-1:

BUS TIMING START/STOP

= +2.5V to 6.0V

Commercial (C):

Tamb

= 0°C to +70°C

Industrial (I):

Tamb

= -40°C to +85°C

Parameter

Symbol

Min

Max

Units

Conditions

A0, A1, A2, SCL and SDA pins:

High level input voltage

.7 V

—

Low level input voltage

—

.3 Vcc

Hysteresis of Schmitt Trigger inputs

HYS

.05 V

—

(Note)

Low level output voltage

—

.40

= 3.0 mA

Input leakage current

-10

= .1V to V

Output leakage current

-10

OUT

= .1V to V

Pin capacitance
(all inputs/outputs)

OUT

—

= 5.0V (Note)

Tamb = 25°C, Fclk = 1 MHz

Operating current

Write

Read

—
—

150

= 6.0V, SCL = 400 kHz

Standby current

CCS

—

= 5.0V, SCL = SDA = V

A0, A1, A2 = V

Note:

This parameter is periodically sampled and not 100% tested.

STA

HYS

STO

START

STOP

SCL

SDA

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2004 Microchip Technology Inc.

DS21072G-page 3

24LC32

TABLE 1-3:

AC CHARACTERISTICS

FIGURE 1-2:

BUS TIMING DATA

Parameter

Symbol

= 2.5V-6.0V

STD. MODE

= 4.5 - 6.0V

FAST MODE

Units

Remarks

Min

Max

Min

Max

Clock frequency

CLK

—

100

—

400

kHz

Clock high time

HIGH

4000

—

600

—

Clock low time

LOW

4700

—

1300

—

SDA and SCL rise time

—

1000

—

300

(Note1)

SDA and SCL fall time

—

300

—

300

(Note1)

START condition hold time

STA

4000

—

600

—

After this period the first clock
pulse is generated

START condition setup time

STA

4700

—

600

—

Only relevant for repeated
START condition

Data input hold time

DAT

—

Data input setup time

DAT

250

—

100

—

STOP condition setup time

STO

4000

—

600

—

Output valid from clock

—

3500

—

900

(Note 2)

Bus free time

BUF

4700

—

1300

—

Time the bus must be free
before a new transmission can
start

Output fall time from V

min

to V

max

—

250

20 +0.1

250

(Note 1), C

≤

100 pF

Input filter spike suppression
(SDA and SCL pins)

—

(Note 3)

Write cycle time

—

ms/page (Note 4)

Endurance

High Endurance Block
Rest of Array

—
—

10M

—
—

10M

—
—

cycles

25°C, Vcc = 5.0V, Block Mode
(Note 5)

Note 1: Not 100% tested. C

= total capacitance of one bus line in pF.

2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region

(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of START or STOP conditions.

3: The combined T

and V

HYS

specifications are due to new Schmitt trigger inputs which provide improved

noise and spike suppression. This eliminates the need for a Ti specification for standard operation.

4: The times shown are for a single page of 8 bytes. Multiply by the number of pages loaded into the write

cache for total time.

5: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-

cation, please consult the Total Endurance Model which can be obtained from our website.

SCL

SDA
IN

SDA
OUT

STA

LOW

HIGH

STA

DAT

STO

BUF

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24LC32

DS21072G-page 4



2004 Microchip Technology Inc.

2.0

FUNCTIONAL DESCRIPTION

3.0

BUS CHARACTERISTICS

The following bus protocol has been defined:

• Data transfer may be initiated only when the bus

is not busy.

• During data transfer, the data line must remain

stable whenever the clock line is HIGH. Changes
in the data line while the clock line is HIGH will be
interpreted as a START or STOP condition.

Accordingly, the following bus conditions have been
defined (Figure 3-1).

3.1

Bus not Busy (A)

Both data and clock lines remain HIGH.

3.2

Start Data Transfer (B)

A HIGH to LOW transition of the SDA line while the
clock (SCL) is HIGH determines a START condition.
All commands must be preceded by a START condi-
tion.

3.3

Stop Data Transfer (C)

A LOW to HIGH transition of the SDA line while the
clock (SCL) is HIGH determines a STOP condition. All
operations must be ended with a STOP condition.

3.4

Data Valid (D)

The state of the data line represents valid data when,
after a START condition, the data line is stable for the
duration of the HIGH period of the clock signal.

The data on the line must be changed during the LOW
period of the clock signal. There is one clock pulse per
bit of data.

3.5

Acknowledge

Note:

The 24LC32 does not generate any
acknowledge bits if an internal program-
ming cycle is in progress.

FIGURE 3-1:

DATA TRANSFER SEQUENCE ON THE SERIAL BUS

SCL

SDA

(A)

(B)

(D)

(A)

(C)

START

CONDITION

ADDRESS OR

ACKNOWLEDGE

VALID

DATA

ALLOWED

TO CHANGE

STOP

CONDITION

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2004 Microchip Technology Inc.

DS21072G-page 5

24LC32

3.6

Device Addressing

FIGURE 3-2:

CONTROL BYTE
ALLOCATION

Operation

Control

Code

Device Select

R/W

Read

1010

Device Address

Write

1010

Device Address

SLAVE ADDRESS

R/W

START

READ/WRITE

FIGURE 3-3:

ADDRESS SEQUENCE BIT ASSIGNMENTS

0 R/W

•

SLAVE

ADDRESS

DEVICE

SELECT

BUS

CONTROL BYTE

ADDRESS BYTE 1

ADDRESS BYTE 0

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24LC32

DS21072G-page 6



2004 Microchip Technology Inc.

4.0

WRITE OPERATION

4.1

Split Endurance

4.2

Byte Write

The 24LC32 acknowledges again and the master gen-
erates a stop condition. This initiates the internal write
cycle, and during this time the 24LC32 will not generate
acknowledge signals (Figure 4-1).

4.3

Page Write

FIGURE 4-1:

BYTE WRITE

FIGURE 4-2:

PAGE WRITE (FOR CACHE WRITE, SEE FIGURE 7-1)

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (0)

DATA

A
C
K

S
T
O
P

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (2)

DATA n

A
C
K

S
T
O
P

DATA n + 7

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2004 Microchip Technology Inc.

DS21072G-page 7

24LC32

5.0

ACKNOWLEDGE POLLING

FIGURE 5-1:

ACKNOWLEDGE POLLING
FLOW

Send

Write Command

Send Stop

Condition to

Initiate Write Cycle

Send Start

Send Control Byte

with R/W = 0

Did Device

Acknowledge

(ACK = 0)?

Operation

YES

6.0

READ OPERATION

6.1

Current Address Read

6.2

Random Read

FIGURE 6-1:

CURRENT ADDRESS READ

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

S
T
O
P

CONTROL

BYTE

DATA n

A
C
K

N
O

A
C
K

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24LC32

DS21072G-page 8



2004 Microchip Technology Inc.

6.3

Contiguous Addressing Across
Multiple Devices

6.4

Sequential Read

6.5

Noise Protection

FIGURE 6-2:

RANDOM READ

FIGURE 6-3:

SEQUENTIAL READ

SDA LINE

BUS

CONTROL

BYTE

WORD

ADDRESS (1)

S
T

S
T
A

A
C
K

ACTIVITY:

N
O

DATA n

0 0 0

WORD

ADDRESS (0)

A
R

CONTROL

BYTE

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
O
P

CONTROL

BYTE

A
C
K

N
O

DATA n

DATA n + 1

DATA n + 2

DATA n + X

A
C
K

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2004 Microchip Technology Inc.

DS21072G-page 9

24LC32

6.6

PAGE CACHE AND ARRAY MAPPING

6.7

Cache Write Starting at a Page
Boundary

6.8

Cache Write Starting at a Non-Page
Boundary

6.9

Power Management

monitor circuitry to prevent inadvertent writes (data cor-
ruption) during low-voltage conditions. The V

moni-

tor circuitry is powered off when the device is in standby
mode in order to further reduce power consumption.

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24LC32

DS21072G-page 10



2004 Microchip Technology Inc.

7.0

PIN DESCRIPTIONS

7.1

A0, A1, A2 Chip Address Inputs

7.2

SDA Serial Address/Data Input/Output

This is a bidirectional pin used to transfer addresses
and data into and data out of the device. It is an open
drain terminal, therefore the SDA bus requires a pullup
resistor to V

(typical 10K

Ω

for 100 kHz, 2 K

Ω

for

400 kHz)

For normal data transfer SDA is allowed to change only
during SCL low. Changes during SCL high are
reserved for indicating the START and STOP condi-
tions.

7.3

SCL Serial Clock

This input is used to synchronize the data transfer from
and to the device.

FIGURE 7-1:

CACHE WRITE TO THE ARRAY STARTING AT A PAGE BOUNDARY

FIGURE 7-2:

CACHE WRITE TO THE ARRAY STARTING AT A NON-PAGE BOUNDARY

1 Write command initiated at byte 0 of page 3 in the array;

First data byte is loaded into the cache byte 0.

2 64 bytes of data are loaded into cache.

3 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

4 Remaining pages in cache are written

to sequential pages in array.

cache

byte 0

cache

byte 1

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

byte 7

• • •

page 4

• • •

page 7

page 3

cache page 0

Last page in cache written to page 2 in next row.

array row n

array row n + 1

page 0 page 1 page 2

byte 0

byte 1

page 4

page 7

1 Write command initiated; 64 bytes of data

loaded into cache starting at byte 2 of page 0.

2 Last 2 bytes loaded 'roll over'

to beginning.

Last 2 bytes
loaded into
page 0 of cache.

4 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

cache

byte 1

cache

byte 2

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

page 4

• • •

page 7

page 3

Remaining bytes in cache are
written sequentially to array.

array

row n

array

row

n + 1

cache

byte 0

Last 3 pages in cache written to next row in array.

page 1 page 2

byte 0

byte 2

byte 1

page 4

page 7

byte 7

byte 3

byte 4

page 0

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

2004 Microchip Technology Inc.

DS21072G-page 1

FEATURES

• Voltage operating range: 2.5V to 6.0V

- Peak write current 3 mA at 6.0V
- Maximum read current 150

A at 6.0V

- Standby current 1

A typical

• Industry standard two-wire bus protocol, I



compatible
- Including 100 kHz (2.5V) and 400 kHz (5V) modes

• Self-timed ERASE and WRITE cycles
• Power on/off data protection circuitry
• Endurance:

- 10,000,000 Erase/Write cycles

guaranteed for High Endurance Block

- 1,000,000 E/W cycles guaranteed for

Standard Endurance Block

• 8 byte page, or byte modes available
• 1 page x 8 line input cache (64 bytes) for fast write

loads

bus for up to 256K bits total memory

• Electrostatic discharge protection > 4000V
• Data retention > 200 years
• 8-pin PDIP/SOIC packages
• Temperature ranges

DESCRIPTION

- Commercial (C):

0°C to +70°C

- Industrial (I):

-40° to

+85°

PACKAGE TYPES

BLOCK DIAGRAM

24L

SCL

SDA

24L

C32

SCL

SDA

PDIP

SOIC

HV GENERATOR

EEPROM

ARRAY

PAGE LATCHES

YDEC

XDEC

SENSE AMP

MEMORY

CONTROL

LOGIC

I/O

CONTROL

LOGIC

SDA

SCL

I/O

CACHE

R/W CONTROL

24LC32

32K 2.5V I

™

Smart Serial EEPROM

C is a trademark of Philips Corporation. Smart Serial is a trademark of Microchip Technology Inc.

Obsolete Device

Please use 24LC32A or 24LC65.

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/21072G-html.html

24LC32

DS21072G-page 2



2004 Microchip Technology Inc.

1.0

ELECTRICAL
CHARACTERISTICS

1.1

Maximum Ratings*

..................................................................................7.0V

All inputs and outputs w.r.t. V

............... -0.6V to V

+1.0V

..................................................≥

4 kV

TABLE 1-1:

PIN FUNCTION TABLE

Name

Function

A0,A1,A2

User Configurable Chip Selects

Ground

SDA

Serial Address/Data I/O

SCL

Serial Clock

+2.5V to 6.0V Power Supply

No Internal Connection

TABLE 1-2:

DC CHARACTERISTICS

FIGURE 1-1:

BUS TIMING START/STOP

= +2.5V to 6.0V

Commercial (C):

Tamb

= 0°C to +70°C

Industrial (I):

Tamb

= -40°C to +85°C

Parameter

Symbol

Min

Max

Units

Conditions

A0, A1, A2, SCL and SDA pins:

High level input voltage

.7 V

—

Low level input voltage

—

.3 Vcc

Hysteresis of Schmitt Trigger inputs

HYS

.05 V

—

(Note)

Low level output voltage

—

.40

= 3.0 mA

Input leakage current

-10

= .1V to V

Output leakage current

-10

OUT

= .1V to V

Pin capacitance
(all inputs/outputs)

OUT

—

= 5.0V (Note)

Tamb = 25°C, Fclk = 1 MHz

Operating current

Write

Read

—
—

150

= 6.0V, SCL = 400 kHz

Standby current

CCS

—

= 5.0V, SCL = SDA = V

A0, A1, A2 = V

Note:

This parameter is periodically sampled and not 100% tested.

STA

HYS

STO

START

STOP

SCL

SDA

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2004 Microchip Technology Inc.

DS21072G-page 3

24LC32

TABLE 1-3:

AC CHARACTERISTICS

FIGURE 1-2:

BUS TIMING DATA

Parameter

Symbol

= 2.5V-6.0V

STD. MODE

= 4.5 - 6.0V

FAST MODE

Units

Remarks

Min

Max

Min

Max

Clock frequency

CLK

—

100

—

400

kHz

Clock high time

HIGH

4000

—

600

—

Clock low time

LOW

4700

—

1300

—

SDA and SCL rise time

—

1000

—

300

(Note1)

SDA and SCL fall time

—

300

—

300

(Note1)

START condition hold time

STA

4000

—

600

—

After this period the first clock
pulse is generated

START condition setup time

STA

4700

—

600

—

Only relevant for repeated
START condition

Data input hold time

DAT

—

Data input setup time

DAT

250

—

100

—

STOP condition setup time

STO

4000

—

600

—

Output valid from clock

—

3500

—

900

(Note 2)

Bus free time

BUF

4700

—

1300

—

Time the bus must be free
before a new transmission can
start

Output fall time from V

min

to V

max

—

250

20 +0.1

250

(Note 1), C

≤

100 pF

Input filter spike suppression
(SDA and SCL pins)

—

(Note 3)

Write cycle time

—

ms/page (Note 4)

Endurance

High Endurance Block
Rest of Array

—
—

10M

—
—

10M

—
—

cycles

25°C, Vcc = 5.0V, Block Mode
(Note 5)

Note 1: Not 100% tested. C

= total capacitance of one bus line in pF.

2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region

(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of START or STOP conditions.

3: The combined T

and V

HYS

specifications are due to new Schmitt trigger inputs which provide improved

noise and spike suppression. This eliminates the need for a Ti specification for standard operation.

4: The times shown are for a single page of 8 bytes. Multiply by the number of pages loaded into the write

cache for total time.

5: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-

cation, please consult the Total Endurance Model which can be obtained from our website.

SCL

SDA
IN

SDA
OUT

STA

LOW

HIGH

STA

DAT

STO

BUF

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24LC32

DS21072G-page 4



2004 Microchip Technology Inc.

2.0

FUNCTIONAL DESCRIPTION

3.0

BUS CHARACTERISTICS

The following bus protocol has been defined:

• Data transfer may be initiated only when the bus

is not busy.

• During data transfer, the data line must remain

stable whenever the clock line is HIGH. Changes
in the data line while the clock line is HIGH will be
interpreted as a START or STOP condition.

Accordingly, the following bus conditions have been
defined (Figure 3-1).

3.1

Bus not Busy (A)

Both data and clock lines remain HIGH.

3.2

Start Data Transfer (B)

A HIGH to LOW transition of the SDA line while the
clock (SCL) is HIGH determines a START condition.
All commands must be preceded by a START condi-
tion.

3.3

Stop Data Transfer (C)

A LOW to HIGH transition of the SDA line while the
clock (SCL) is HIGH determines a STOP condition. All
operations must be ended with a STOP condition.

3.4

Data Valid (D)

The state of the data line represents valid data when,
after a START condition, the data line is stable for the
duration of the HIGH period of the clock signal.

The data on the line must be changed during the LOW
period of the clock signal. There is one clock pulse per
bit of data.

3.5

Acknowledge

Note:

The 24LC32 does not generate any
acknowledge bits if an internal program-
ming cycle is in progress.

FIGURE 3-1:

DATA TRANSFER SEQUENCE ON THE SERIAL BUS

SCL

SDA

(A)

(B)

(D)

(A)

(C)

START

CONDITION

ADDRESS OR

ACKNOWLEDGE

VALID

DATA

ALLOWED

TO CHANGE

STOP

CONDITION

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2004 Microchip Technology Inc.

DS21072G-page 5

24LC32

3.6

Device Addressing

FIGURE 3-2:

CONTROL BYTE
ALLOCATION

Operation

Control

Code

Device Select

R/W

Read

1010

Device Address

Write

1010

Device Address

SLAVE ADDRESS

R/W

START

READ/WRITE

FIGURE 3-3:

ADDRESS SEQUENCE BIT ASSIGNMENTS

0 R/W

•

SLAVE

ADDRESS

DEVICE

SELECT

BUS

CONTROL BYTE

ADDRESS BYTE 1

ADDRESS BYTE 0

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24LC32

DS21072G-page 6



2004 Microchip Technology Inc.

4.0

WRITE OPERATION

4.1

Split Endurance

4.2

Byte Write

The 24LC32 acknowledges again and the master gen-
erates a stop condition. This initiates the internal write
cycle, and during this time the 24LC32 will not generate
acknowledge signals (Figure 4-1).

4.3

Page Write

FIGURE 4-1:

BYTE WRITE

FIGURE 4-2:

PAGE WRITE (FOR CACHE WRITE, SEE FIGURE 7-1)

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (0)

DATA

A
C
K

S
T
O
P

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (2)

DATA n

A
C
K

S
T
O
P

DATA n + 7

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2004 Microchip Technology Inc.

DS21072G-page 7

24LC32

5.0

ACKNOWLEDGE POLLING

FIGURE 5-1:

ACKNOWLEDGE POLLING
FLOW

Send

Write Command

Send Stop

Condition to

Initiate Write Cycle

Send Start

Send Control Byte

with R/W = 0

Did Device

Acknowledge

(ACK = 0)?

Operation

YES

6.0

READ OPERATION

6.1

Current Address Read

6.2

Random Read

FIGURE 6-1:

CURRENT ADDRESS READ

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

S
T
O
P

CONTROL

BYTE

DATA n

A
C
K

N
O

A
C
K

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24LC32

DS21072G-page 8



2004 Microchip Technology Inc.

6.3

Contiguous Addressing Across
Multiple Devices

6.4

Sequential Read

6.5

Noise Protection

FIGURE 6-2:

RANDOM READ

FIGURE 6-3:

SEQUENTIAL READ

SDA LINE

BUS

CONTROL

BYTE

WORD

ADDRESS (1)

S
T

S
T
A

A
C
K

ACTIVITY:

N
O

DATA n

0 0 0

WORD

ADDRESS (0)

A
R

CONTROL

BYTE

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
O
P

CONTROL

BYTE

A
C
K

N
O

DATA n

DATA n + 1

DATA n + 2

DATA n + X

A
C
K

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2004 Microchip Technology Inc.

DS21072G-page 9

24LC32

6.6

PAGE CACHE AND ARRAY MAPPING

6.7

Cache Write Starting at a Page
Boundary

6.8

Cache Write Starting at a Non-Page
Boundary

6.9

Power Management

monitor circuitry to prevent inadvertent writes (data cor-
ruption) during low-voltage conditions. The V

moni-

tor circuitry is powered off when the device is in standby
mode in order to further reduce power consumption.

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24LC32

DS21072G-page 10



2004 Microchip Technology Inc.

7.0

PIN DESCRIPTIONS

7.1

A0, A1, A2 Chip Address Inputs

7.2

SDA Serial Address/Data Input/Output

This is a bidirectional pin used to transfer addresses
and data into and data out of the device. It is an open
drain terminal, therefore the SDA bus requires a pullup
resistor to V

(typical 10K

Ω

for 100 kHz, 2 K

Ω

for

400 kHz)

For normal data transfer SDA is allowed to change only
during SCL low. Changes during SCL high are
reserved for indicating the START and STOP condi-
tions.

7.3

SCL Serial Clock

This input is used to synchronize the data transfer from
and to the device.

FIGURE 7-1:

CACHE WRITE TO THE ARRAY STARTING AT A PAGE BOUNDARY

FIGURE 7-2:

CACHE WRITE TO THE ARRAY STARTING AT A NON-PAGE BOUNDARY

1 Write command initiated at byte 0 of page 3 in the array;

First data byte is loaded into the cache byte 0.

2 64 bytes of data are loaded into cache.

3 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

4 Remaining pages in cache are written

to sequential pages in array.

cache

byte 0

cache

byte 1

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

byte 7

• • •

page 4

• • •

page 7

page 3

cache page 0

Last page in cache written to page 2 in next row.

array row n

array row n + 1

page 0 page 1 page 2

byte 0

byte 1

page 4

page 7

1 Write command initiated; 64 bytes of data

loaded into cache starting at byte 2 of page 0.

2 Last 2 bytes loaded 'roll over'

to beginning.

Last 2 bytes
loaded into
page 0 of cache.

4 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

cache

byte 1

cache

byte 2

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

page 4

• • •

page 7

page 3

Remaining bytes in cache are
written sequentially to array.

array

row n

array

row

n + 1

cache

byte 0

Last 3 pages in cache written to next row in array.

page 1 page 2

byte 0

byte 2

byte 1

page 4

page 7

byte 7

byte 3

byte 4

page 0

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2004 Microchip Technology Inc.

DS21072G-page 1

FEATURES

• Voltage operating range: 2.5V to 6.0V

- Peak write current 3 mA at 6.0V
- Maximum read current 150

A at 6.0V

- Standby current 1

A typical

• Industry standard two-wire bus protocol, I



compatible
- Including 100 kHz (2.5V) and 400 kHz (5V) modes

• Self-timed ERASE and WRITE cycles
• Power on/off data protection circuitry
• Endurance:

- 10,000,000 Erase/Write cycles

guaranteed for High Endurance Block

- 1,000,000 E/W cycles guaranteed for

Standard Endurance Block

• 8 byte page, or byte modes available
• 1 page x 8 line input cache (64 bytes) for fast write

loads

bus for up to 256K bits total memory

• Electrostatic discharge protection > 4000V
• Data retention > 200 years
• 8-pin PDIP/SOIC packages
• Temperature ranges

DESCRIPTION

- Commercial (C):

0°C to +70°C

- Industrial (I):

-40° to

+85°

PACKAGE TYPES

BLOCK DIAGRAM

24L

SCL

SDA

24L

C32

SCL

SDA

PDIP

SOIC

HV GENERATOR

EEPROM

ARRAY

PAGE LATCHES

YDEC

XDEC

SENSE AMP

MEMORY

CONTROL

LOGIC

I/O

CONTROL

LOGIC

SDA

SCL

I/O

CACHE

R/W CONTROL

24LC32

32K 2.5V I

™

Smart Serial EEPROM

C is a trademark of Philips Corporation. Smart Serial is a trademark of Microchip Technology Inc.

Obsolete Device

Please use 24LC32A or 24LC65.

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24LC32

DS21072G-page 2



2004 Microchip Technology Inc.

1.0

ELECTRICAL
CHARACTERISTICS

1.1

Maximum Ratings*

..................................................................................7.0V

All inputs and outputs w.r.t. V

............... -0.6V to V

+1.0V

..................................................≥

4 kV

TABLE 1-1:

PIN FUNCTION TABLE

Name

Function

A0,A1,A2

User Configurable Chip Selects

Ground

SDA

Serial Address/Data I/O

SCL

Serial Clock

+2.5V to 6.0V Power Supply

No Internal Connection

TABLE 1-2:

DC CHARACTERISTICS

FIGURE 1-1:

BUS TIMING START/STOP

= +2.5V to 6.0V

Commercial (C):

Tamb

= 0°C to +70°C

Industrial (I):

Tamb

= -40°C to +85°C

Parameter

Symbol

Min

Max

Units

Conditions

A0, A1, A2, SCL and SDA pins:

High level input voltage

.7 V

—

Low level input voltage

—

.3 Vcc

Hysteresis of Schmitt Trigger inputs

HYS

.05 V

—

(Note)

Low level output voltage

—

.40

= 3.0 mA

Input leakage current

-10

= .1V to V

Output leakage current

-10

OUT

= .1V to V

Pin capacitance
(all inputs/outputs)

OUT

—

= 5.0V (Note)

Tamb = 25°C, Fclk = 1 MHz

Operating current

Write

Read

—
—

150

= 6.0V, SCL = 400 kHz

Standby current

CCS

—

= 5.0V, SCL = SDA = V

A0, A1, A2 = V

Note:

This parameter is periodically sampled and not 100% tested.

STA

HYS

STO

START

STOP

SCL

SDA

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2004 Microchip Technology Inc.

DS21072G-page 3

24LC32

TABLE 1-3:

AC CHARACTERISTICS

FIGURE 1-2:

BUS TIMING DATA

Parameter

Symbol

= 2.5V-6.0V

STD. MODE

= 4.5 - 6.0V

FAST MODE

Units

Remarks

Min

Max

Min

Max

Clock frequency

CLK

—

100

—

400

kHz

Clock high time

HIGH

4000

—

600

—

Clock low time

LOW

4700

—

1300

—

SDA and SCL rise time

—

1000

—

300

(Note1)

SDA and SCL fall time

—

300

—

300

(Note1)

START condition hold time

STA

4000

—

600

—

After this period the first clock
pulse is generated

START condition setup time

STA

4700

—

600

—

Only relevant for repeated
START condition

Data input hold time

DAT

—

Data input setup time

DAT

250

—

100

—

STOP condition setup time

STO

4000

—

600

—

Output valid from clock

—

3500

—

900

(Note 2)

Bus free time

BUF

4700

—

1300

—

Time the bus must be free
before a new transmission can
start

Output fall time from V

min

to V

max

—

250

20 +0.1

250

(Note 1), C

≤

100 pF

Input filter spike suppression
(SDA and SCL pins)

—

(Note 3)

Write cycle time

—

ms/page (Note 4)

Endurance

High Endurance Block
Rest of Array

—
—

10M

—
—

10M

—
—

cycles

25°C, Vcc = 5.0V, Block Mode
(Note 5)

Note 1: Not 100% tested. C

= total capacitance of one bus line in pF.

2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region

(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of START or STOP conditions.

3: The combined T

and V

HYS

specifications are due to new Schmitt trigger inputs which provide improved

noise and spike suppression. This eliminates the need for a Ti specification for standard operation.

4: The times shown are for a single page of 8 bytes. Multiply by the number of pages loaded into the write

cache for total time.

5: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-

cation, please consult the Total Endurance Model which can be obtained from our website.

SCL

SDA
IN

SDA
OUT

STA

LOW

HIGH

STA

DAT

STO

BUF

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24LC32

DS21072G-page 4

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2004 Microchip Technology Inc.

2.0

FUNCTIONAL DESCRIPTION

3.0

BUS CHARACTERISTICS

The following bus protocol has been defined:

• Data transfer may be initiated only when the bus

is not busy.

• During data transfer, the data line must remain

stable whenever the clock line is HIGH. Changes
in the data line while the clock line is HIGH will be
interpreted as a START or STOP condition.

Accordingly, the following bus conditions have been
defined (Figure 3-1).

3.1

Bus not Busy (A)

Both data and clock lines remain HIGH.

3.2

Start Data Transfer (B)

A HIGH to LOW transition of the SDA line while the
clock (SCL) is HIGH determines a START condition.
All commands must be preceded by a START condi-
tion.

3.3

Stop Data Transfer (C)

A LOW to HIGH transition of the SDA line while the
clock (SCL) is HIGH determines a STOP condition. All
operations must be ended with a STOP condition.

3.4

Data Valid (D)

The state of the data line represents valid data when,
after a START condition, the data line is stable for the
duration of the HIGH period of the clock signal.

The data on the line must be changed during the LOW
period of the clock signal. There is one clock pulse per
bit of data.

3.5

Acknowledge

Note:

The 24LC32 does not generate any
acknowledge bits if an internal program-
ming cycle is in progress.

FIGURE 3-1:

DATA TRANSFER SEQUENCE ON THE SERIAL BUS

SCL

SDA

(A)

(B)

(D)

(A)

(C)

START

CONDITION

ADDRESS OR

ACKNOWLEDGE

VALID

DATA

ALLOWED

TO CHANGE

STOP

CONDITION

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2004 Microchip Technology Inc.

DS21072G-page 5

24LC32

3.6

Device Addressing

FIGURE 3-2:

CONTROL BYTE
ALLOCATION

Operation

Control

Code

Device Select

R/W

Read

1010

Device Address

Write

1010

Device Address

SLAVE ADDRESS

R/W

START

READ/WRITE

FIGURE 3-3:

ADDRESS SEQUENCE BIT ASSIGNMENTS

0 R/W

•

SLAVE

ADDRESS

DEVICE

SELECT

BUS

CONTROL BYTE

ADDRESS BYTE 1

ADDRESS BYTE 0

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24LC32

DS21072G-page 6



2004 Microchip Technology Inc.

4.0

WRITE OPERATION

4.1

Split Endurance

4.2

Byte Write

The 24LC32 acknowledges again and the master gen-
erates a stop condition. This initiates the internal write
cycle, and during this time the 24LC32 will not generate
acknowledge signals (Figure 4-1).

4.3

Page Write

FIGURE 4-1:

BYTE WRITE

FIGURE 4-2:

PAGE WRITE (FOR CACHE WRITE, SEE FIGURE 7-1)

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (0)

DATA

A
C
K

S
T
O
P

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (2)

DATA n

A
C
K

S
T
O
P

DATA n + 7

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2004 Microchip Technology Inc.

DS21072G-page 7

24LC32

5.0

ACKNOWLEDGE POLLING

FIGURE 5-1:

ACKNOWLEDGE POLLING
FLOW

Send

Write Command

Send Stop

Condition to

Initiate Write Cycle

Send Start

Send Control Byte

with R/W = 0

Did Device

Acknowledge

(ACK = 0)?

Operation

YES

6.0

READ OPERATION

6.1

Current Address Read

6.2

Random Read

FIGURE 6-1:

CURRENT ADDRESS READ

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

S
T
O
P

CONTROL

BYTE

DATA n

A
C
K

N
O

A
C
K

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24LC32

DS21072G-page 8

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2004 Microchip Technology Inc.

6.3

Contiguous Addressing Across
Multiple Devices

6.4

Sequential Read

6.5

Noise Protection

FIGURE 6-2:

RANDOM READ

FIGURE 6-3:

SEQUENTIAL READ

SDA LINE

BUS

CONTROL

BYTE

WORD

ADDRESS (1)

S
T

S
T
A

A
C
K

ACTIVITY:

N
O

DATA n

0 0 0

WORD

ADDRESS (0)

A
R

CONTROL

BYTE

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
O
P

CONTROL

BYTE

A
C
K

N
O

DATA n

DATA n + 1

DATA n + 2

DATA n + X

A
C
K

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2004 Microchip Technology Inc.

DS21072G-page 9

24LC32

6.6

PAGE CACHE AND ARRAY MAPPING

6.7

Cache Write Starting at a Page
Boundary

6.8

Cache Write Starting at a Non-Page
Boundary

6.9

Power Management

monitor circuitry to prevent inadvertent writes (data cor-
ruption) during low-voltage conditions. The V

moni-

tor circuitry is powered off when the device is in standby
mode in order to further reduce power consumption.

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24LC32

DS21072G-page 10



2004 Microchip Technology Inc.

7.0

PIN DESCRIPTIONS

7.1

A0, A1, A2 Chip Address Inputs

7.2

SDA Serial Address/Data Input/Output

This is a bidirectional pin used to transfer addresses
and data into and data out of the device. It is an open
drain terminal, therefore the SDA bus requires a pullup
resistor to V

(typical 10K

Ω

for 100 kHz, 2 K

Ω

for

400 kHz)

For normal data transfer SDA is allowed to change only
during SCL low. Changes during SCL high are
reserved for indicating the START and STOP condi-
tions.

7.3

SCL Serial Clock

This input is used to synchronize the data transfer from
and to the device.

FIGURE 7-1:

CACHE WRITE TO THE ARRAY STARTING AT A PAGE BOUNDARY

FIGURE 7-2:

CACHE WRITE TO THE ARRAY STARTING AT A NON-PAGE BOUNDARY

1 Write command initiated at byte 0 of page 3 in the array;

First data byte is loaded into the cache byte 0.

2 64 bytes of data are loaded into cache.

3 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

4 Remaining pages in cache are written

to sequential pages in array.

cache

byte 0

cache

byte 1

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

byte 7

• • •

page 4

• • •

page 7

page 3

cache page 0

Last page in cache written to page 2 in next row.

array row n

array row n + 1

page 0 page 1 page 2

byte 0

byte 1

page 4

page 7

1 Write command initiated; 64 bytes of data

loaded into cache starting at byte 2 of page 0.

2 Last 2 bytes loaded 'roll over'

to beginning.

Last 2 bytes
loaded into
page 0 of cache.

4 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

cache

byte 1

cache

byte 2

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

page 4

• • •

page 7

page 3

Remaining bytes in cache are
written sequentially to array.

array

row n

array

row

n + 1

cache

byte 0

Last 3 pages in cache written to next row in array.

page 1 page 2

byte 0

byte 2

byte 1

page 4

page 7

byte 7

byte 3

byte 4

page 0

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

2004 Microchip Technology Inc.

DS21072G-page 1

FEATURES

• Voltage operating range: 2.5V to 6.0V

- Peak write current 3 mA at 6.0V
- Maximum read current 150

A at 6.0V

- Standby current 1

A typical

• Industry standard two-wire bus protocol, I



compatible
- Including 100 kHz (2.5V) and 400 kHz (5V) modes

• Self-timed ERASE and WRITE cycles
• Power on/off data protection circuitry
• Endurance:

- 10,000,000 Erase/Write cycles

guaranteed for High Endurance Block

- 1,000,000 E/W cycles guaranteed for

Standard Endurance Block

• 8 byte page, or byte modes available
• 1 page x 8 line input cache (64 bytes) for fast write

loads

bus for up to 256K bits total memory

• Electrostatic discharge protection > 4000V
• Data retention > 200 years
• 8-pin PDIP/SOIC packages
• Temperature ranges

DESCRIPTION

- Commercial (C):

0°C to +70°C

- Industrial (I):

-40° to

+85°

PACKAGE TYPES

BLOCK DIAGRAM

24L

SCL

SDA

24L

C32

SCL

SDA

PDIP

SOIC

HV GENERATOR

EEPROM

ARRAY

PAGE LATCHES

YDEC

XDEC

SENSE AMP

MEMORY

CONTROL

LOGIC

I/O

CONTROL

LOGIC

SDA

SCL

I/O

CACHE

R/W CONTROL

24LC32

32K 2.5V I

™

Smart Serial EEPROM

C is a trademark of Philips Corporation. Smart Serial is a trademark of Microchip Technology Inc.

Obsolete Device

Please use 24LC32A or 24LC65.

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/21072G-html.html

24LC32

DS21072G-page 2



2004 Microchip Technology Inc.

1.0

ELECTRICAL
CHARACTERISTICS

1.1

Maximum Ratings*

..................................................................................7.0V

All inputs and outputs w.r.t. V

............... -0.6V to V

+1.0V

..................................................≥

4 kV

TABLE 1-1:

PIN FUNCTION TABLE

Name

Function

A0,A1,A2

User Configurable Chip Selects

Ground

SDA

Serial Address/Data I/O

SCL

Serial Clock

+2.5V to 6.0V Power Supply

No Internal Connection

TABLE 1-2:

DC CHARACTERISTICS

FIGURE 1-1:

BUS TIMING START/STOP

= +2.5V to 6.0V

Commercial (C):

Tamb

= 0°C to +70°C

Industrial (I):

Tamb

= -40°C to +85°C

Parameter

Symbol

Min

Max

Units

Conditions

A0, A1, A2, SCL and SDA pins:

High level input voltage

.7 V

—

Low level input voltage

—

.3 Vcc

Hysteresis of Schmitt Trigger inputs

HYS

.05 V

—

(Note)

Low level output voltage

—

.40

= 3.0 mA

Input leakage current

-10

= .1V to V

Output leakage current

-10

OUT

= .1V to V

Pin capacitance
(all inputs/outputs)

OUT

—

= 5.0V (Note)

Tamb = 25°C, Fclk = 1 MHz

Operating current

Write

Read

—
—

150

= 6.0V, SCL = 400 kHz

Standby current

CCS

—

= 5.0V, SCL = SDA = V

A0, A1, A2 = V

Note:

This parameter is periodically sampled and not 100% tested.

STA

HYS

STO

START

STOP

SCL

SDA

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2004 Microchip Technology Inc.

DS21072G-page 3

24LC32

TABLE 1-3:

AC CHARACTERISTICS

FIGURE 1-2:

BUS TIMING DATA

Parameter

Symbol

= 2.5V-6.0V

STD. MODE

= 4.5 - 6.0V

FAST MODE

Units

Remarks

Min

Max

Min

Max

Clock frequency

CLK

—

100

—

400

kHz

Clock high time

HIGH

4000

—

600

—

Clock low time

LOW

4700

—

1300

—

SDA and SCL rise time

—

1000

—

300

(Note1)

SDA and SCL fall time

—

300

—

300

(Note1)

START condition hold time

STA

4000

—

600

—

After this period the first clock
pulse is generated

START condition setup time

STA

4700

—

600

—

Only relevant for repeated
START condition

Data input hold time

DAT

—

Data input setup time

DAT

250

—

100

—

STOP condition setup time

STO

4000

—

600

—

Output valid from clock

—

3500

—

900

(Note 2)

Bus free time

BUF

4700

—

1300

—

Time the bus must be free
before a new transmission can
start

Output fall time from V

min

to V

max

—

250

20 +0.1

250

(Note 1), C

≤

100 pF

Input filter spike suppression
(SDA and SCL pins)

—

(Note 3)

Write cycle time

—

ms/page (Note 4)

Endurance

High Endurance Block
Rest of Array

—
—

10M

—
—

10M

—
—

cycles

25°C, Vcc = 5.0V, Block Mode
(Note 5)

Note 1: Not 100% tested. C

= total capacitance of one bus line in pF.

2: As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region

(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of START or STOP conditions.

3: The combined T

and V

HYS

specifications are due to new Schmitt trigger inputs which provide improved

noise and spike suppression. This eliminates the need for a Ti specification for standard operation.

4: The times shown are for a single page of 8 bytes. Multiply by the number of pages loaded into the write

cache for total time.

5: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-

cation, please consult the Total Endurance Model which can be obtained from our website.

SCL

SDA
IN

SDA
OUT

STA

LOW

HIGH

STA

DAT

STO

BUF

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2004 Microchip Technology Inc.

2.0

FUNCTIONAL DESCRIPTION

3.0

BUS CHARACTERISTICS

The following bus protocol has been defined:

• Data transfer may be initiated only when the bus

is not busy.

• During data transfer, the data line must remain

stable whenever the clock line is HIGH. Changes
in the data line while the clock line is HIGH will be
interpreted as a START or STOP condition.

Accordingly, the following bus conditions have been
defined (Figure 3-1).

3.1

Bus not Busy (A)

Both data and clock lines remain HIGH.

3.2

Start Data Transfer (B)

A HIGH to LOW transition of the SDA line while the
clock (SCL) is HIGH determines a START condition.
All commands must be preceded by a START condi-
tion.

3.3

Stop Data Transfer (C)

A LOW to HIGH transition of the SDA line while the
clock (SCL) is HIGH determines a STOP condition. All
operations must be ended with a STOP condition.

3.4

Data Valid (D)

The state of the data line represents valid data when,
after a START condition, the data line is stable for the
duration of the HIGH period of the clock signal.

The data on the line must be changed during the LOW
period of the clock signal. There is one clock pulse per
bit of data.

3.5

Acknowledge

Note:

The 24LC32 does not generate any
acknowledge bits if an internal program-
ming cycle is in progress.

FIGURE 3-1:

DATA TRANSFER SEQUENCE ON THE SERIAL BUS

SCL

SDA

(A)

(B)

(D)

(A)

(C)

START

CONDITION

ADDRESS OR

ACKNOWLEDGE

VALID

DATA

ALLOWED

TO CHANGE

STOP

CONDITION

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2004 Microchip Technology Inc.

DS21072G-page 5

24LC32

3.6

Device Addressing

FIGURE 3-2:

CONTROL BYTE
ALLOCATION

Operation

Control

Code

Device Select

R/W

Read

1010

Device Address

Write

1010

Device Address

SLAVE ADDRESS

R/W

START

READ/WRITE

FIGURE 3-3:

ADDRESS SEQUENCE BIT ASSIGNMENTS

0 R/W

•

SLAVE

ADDRESS

DEVICE

SELECT

BUS

CONTROL BYTE

ADDRESS BYTE 1

ADDRESS BYTE 0

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4.0

WRITE OPERATION

4.1

Split Endurance

4.2

Byte Write

The 24LC32 acknowledges again and the master gen-
erates a stop condition. This initiates the internal write
cycle, and during this time the 24LC32 will not generate
acknowledge signals (Figure 4-1).

4.3

Page Write

FIGURE 4-1:

BYTE WRITE

FIGURE 4-2:

PAGE WRITE (FOR CACHE WRITE, SEE FIGURE 7-1)

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (0)

DATA

A
C
K

S
T
O
P

0 0 0 0

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

CONTROL

BYTE

Word

Address (1)

Word

Address (2)

DATA n

A
C
K

S
T
O
P

DATA n + 7

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2004 Microchip Technology Inc.

DS21072G-page 7

24LC32

5.0

ACKNOWLEDGE POLLING

FIGURE 5-1:

ACKNOWLEDGE POLLING
FLOW

Send

Write Command

Send Stop

Condition to

Initiate Write Cycle

Send Start

Send Control Byte

with R/W = 0

Did Device

Acknowledge

(ACK = 0)?

Operation

YES

6.0

READ OPERATION

6.1

Current Address Read

6.2

Random Read

FIGURE 6-1:

CURRENT ADDRESS READ

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
A
R
T

S
T
O
P

CONTROL

BYTE

DATA n

A
C
K

N
O

A
C
K

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2004 Microchip Technology Inc.

6.3

Contiguous Addressing Across
Multiple Devices

6.4

Sequential Read

6.5

Noise Protection

FIGURE 6-2:

RANDOM READ

FIGURE 6-3:

SEQUENTIAL READ

SDA LINE

BUS

CONTROL

BYTE

WORD

ADDRESS (1)

S
T

S
T
A

A
C
K

ACTIVITY:

N
O

DATA n

0 0 0

WORD

ADDRESS (0)

A
R

CONTROL

BYTE

BUS ACTIVITY
MASTER

SDA LINE

BUS ACTIVITY

S
T
O
P

CONTROL

BYTE

A
C
K

N
O

DATA n

DATA n + 1

DATA n + 2

DATA n + X

A
C
K

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DS21072G-page 9

24LC32

6.6

PAGE CACHE AND ARRAY MAPPING

6.7

Cache Write Starting at a Page
Boundary

6.8

Cache Write Starting at a Non-Page
Boundary

6.9

Power Management

monitor circuitry to prevent inadvertent writes (data cor-
ruption) during low-voltage conditions. The V

moni-

tor circuitry is powered off when the device is in standby
mode in order to further reduce power consumption.

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2004 Microchip Technology Inc.

7.0

PIN DESCRIPTIONS

7.1

A0, A1, A2 Chip Address Inputs

7.2

SDA Serial Address/Data Input/Output

This is a bidirectional pin used to transfer addresses
and data into and data out of the device. It is an open
drain terminal, therefore the SDA bus requires a pullup
resistor to V

(typical 10K

Ω

for 100 kHz, 2 K

Ω

for

400 kHz)

For normal data transfer SDA is allowed to change only
during SCL low. Changes during SCL high are
reserved for indicating the START and STOP condi-
tions.

7.3

SCL Serial Clock

This input is used to synchronize the data transfer from
and to the device.

FIGURE 7-1:

CACHE WRITE TO THE ARRAY STARTING AT A PAGE BOUNDARY

FIGURE 7-2:

CACHE WRITE TO THE ARRAY STARTING AT A NON-PAGE BOUNDARY

1 Write command initiated at byte 0 of page 3 in the array;

First data byte is loaded into the cache byte 0.

2 64 bytes of data are loaded into cache.

3 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

4 Remaining pages in cache are written

to sequential pages in array.

cache

byte 0

cache

byte 1

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

byte 7

• • •

page 4

• • •

page 7

page 3

cache page 0

Last page in cache written to page 2 in next row.

array row n

array row n + 1

page 0 page 1 page 2

byte 0

byte 1

page 4

page 7

1 Write command initiated; 64 bytes of data

loaded into cache starting at byte 2 of page 0.

2 Last 2 bytes loaded 'roll over'

to beginning.

Last 2 bytes
loaded into
page 0 of cache.

4 Write from cache into array initiated by STOP bit.

Page 0 of cache written to page 3 of array.
Write cycle is executed after every page is written.

cache

byte 1

cache

byte 2

• • •

cache

byte 7

cache page 1

bytes 8-15

• • •

page 0

cache page 2

bytes 16-23

cache page 7

bytes 56-63

page 1 page 2

• • •

page 4

• • •

page 7

page 3

Remaining bytes in cache are
written sequentially to array.

array

row n

array

row

n + 1

cache

byte 0

Last 3 pages in cache written to next row in array.

page 1 page 2

byte 0

byte 2

byte 1

page 4

page 7

byte 7

byte 3

byte 4

page 0

Maker

Microchip Technology Inc.

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