TC1232 Data Sheet

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

 2002-2014 Microchip Technology Inc.

DS20001370E-page 1

TC1232

Features:

• Precision Voltage Monitor:

- Adjustable +4.5V or +4.75V

• Reset Pulse Width – 250 ms minimum

• No External Components

• Adjustable Watchdog Timer:

- 150 ms, 600 ms or 1.2s

• Operating Voltage 4.0V to 5.5V

• Debounced Manual Reset Input for External 

Override

Block Diagram

General Description:

The TC1232 is a fully-integrated processor supervisor
that provides three important functions to safeguard
processor sanity: precision power on/off Reset control,
Watchdog Timer and external Reset override.

On power-up, the TC1232 holds the processor in the
Reset state for a minimum of 250 ms after V

CC

 is within

tolerance to ensure a stable system start-up.

Microprocessor sanity is monitored by the on-board
watchdog circuit. The microprocessor must provide a
periodic low-going signal on the ST input. Should the
processor fail to supply this signal within the selected
time-out period (150 ms, 600 ms or 1200 ms), an out-
of-control processor is indicated and the TC1232
issues a processor Reset as a result.

The outputs of the TC1232 are immediately driven
active when the PB input is brought low by an external
push button switch or other electronic signal. When
connected to a push button switch, the TC1232
provides contact debounce.

The TC1232 is packaged in a space-saving 8-Pin PDIP
or SOIC package, a 16-Pin SOIC (wide) package and
requires no external components.

Package Types

Device Features

+

– 

V

REF

+

+

– 

RST

RST

Tolerance

Select 

(5% or 10%) 

TOL

V

CC

Debounce

Watchdog

Timebase

Select

PB RST

TD

Watchdog

Timer

ST

Reset

Generator

Device

RST pin

RST pin

Trip Points 

(Max)

Minimum 

Reset 

Active Time 

(ms)

WDI Input 

Typical 

Timeouts (ms)

MR 

Input

Type

Pull-up 

Resistor

Active 

Level

Type

Active 

Level

TC1232

Open-drain

External

Low

Push-pull

High

4.75V

or 4.5V

250

150, 600 or 

1200

Yes

13

12

11

10

9

15
14

1

8

2

7

3

6

4

5

TC1232

 

RST

RST

GND

TOL

TD

PB RST

RST

ST

V

CC

RST

ST

1

8

2

7

3

6

4

5

RST

GND

TOL

TD

PB RST

RST

ST

V

CC

PB RST

VCC

1
2
3
4

5

6
7
8

16

NC

TD

NC

NC

TOL

GND

NC

NC

NC

TC1232

 

NC

NC

16-Pin SOIC (Wide)

8-Pin PDIP

8-Pin SOIC

TC1232

1

8

3

6

4

5

TC1232

Microprocessor Monitor

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

TC1232

DS20001370E-page 2

 2002-2014 Microchip Technology Inc.

1.0

ELECTRICAL 
CHARACTERISTICS

Absolute Maximum Ratings†

Voltage on Any Pin (With Respect to GND)
         ...................................................... -0.3V to +5.8V

Operating Temperature Range:

        C-Version ........................................ 0°C to +70°C
        E-Version...................................... -40°C to +85°C

Storage Temperature Range:  ............-65°C to +150°C

† Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to the device. These
are stress ratings only and functional operation of the device
at these or any other conditions above those indicated in the
operation sections of the specifications is not implied.
Exposure to Absolute Maximum Rating conditions for
extended periods may affect device reliability.

DC CHARACTERISTICS

Electrical Specifications: Unless otherwise noted, T

A

 = T

MIN

 to T

MAX

; V

CC

 = +4.0V to 5.5V.

Parameters

Sym.

Min.

Typ.

Max.

Units

Conditions

Supply Voltage

V

CC

4.0

5.0

5.5

V

ST and PB RST Input High Level

V

IH

2.0

V

CC

 +0.3

V

Note 1

ST and PB RST Input Low Level

V

IL

-0.3

+0.8

V

Input Leakage ST, TOL

I

L

-1.0

+1.0

µA

Output Current RST

I

OH

-1.0

-12

mA

V

OH

 = 2.4V

Current RST, RST

I

OL

2.0

10

mA

V

OL

 = 0.4V

Operating Current

I

CC

50

200

µA

Note 2

V

CC

 5% Trip Point

V

CCTP

4.50

4.62

4.74

V

TOL = GND (

Note 3

)

V

CC

 10% Trip Point

V

CCTP

4.25

4.37

4.49

V

TOL = V

CC

 (

Note 3

)

Capacitance Electrical Characteristics: Unless otherwise noted, T

A

 = +25°C. (

Note 4

)

Input Capacitance ST, TOL

C

IN

5

pF

Output Capacitance RST, RST

C

OUT

7

pF

Note 1:

PB RST is internally pulled up to V

CC

 with an internal impedance of typically 40 k

.

2:

Measured with outputs open.

3:

All voltages referenced to GND.

4:

Ensured by design.

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

 2002-2014 Microchip Technology Inc.

DS20001370E-page 3

TC1232

       

FIGURE 1-1:

Rise Time, Fall Time and Reset Detected to Reset Active Timing Waveforms.

AC CHARACTERISTICS

Electrical Specifications: Unless otherwise noted, T

A

 = T

MIN

 to T

MAX

; V

CC

 = +4.0V to 5.5V.

Parameters

Sym.

Min.

Typ.

Max.

Units

Conditions

V

CC

 Fall Time

t

F

10

µs

Note 1

V

CC

 Rise Time 

t

R

0

µs

Note 1

V

CC

 Trip Point Detected 

to RST High and RST Low

t

RPD

100

ns

V

CC

 falling

V

CC

 Trip Point Detected 

to RST High and RST Open

t

RPU

250

610

1000

ms

V

CC

 rising (

Note 2

)

Note 1:

Ensured by design.

2:

t

R

 = 5 µs.

+4.75V

t

F

V

CC

+4.25V

t

R

V

CC

+4.25V

+4.75V

V

CC

 = 5V

+4.5V (5% Trip Point)

+4.25V (10% Trip Point)

RST

RST

V

OL

V

OH

 t

RPD

V

CC

4.6V (5% Trip Point)

4.5V(10% Trip Point)

RST

RST

V

OL

V

OH

 t

RPU

Determined by
external Pull-up
resistor

Determined by
external Pull-up
resistor

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

TC1232

DS20001370E-page 4

 2002-2014 Microchip Technology Inc.

       

FIGURE 1-2:

Push Button Reset and Watchdog Timer Reset Timing Waveforms.

AC CHARACTERISTICS (CONTINUED)

Electrical Specifications: Unless otherwise noted, T

A

 = T

MIN

 to T

MAX

; V

CC

 = +4.0V to 5.5V.

Parameters

Sym.

Min.

Typ.

Max.

Units

Conditions

PB RST Pulse Width 

t

PB

20

ms

Note 1

PB RST Falling Edge Low to 
Reset Active

t

PBD

1

4

20

ms

PB RST Rising Edge High to 
Reset Inactive

t

RST

250

610

1000

ms

ST Pulse Width

t

ST

20

ns

ST Time-out Period

t

TD

62.5

150

250

ms

TD Pin = 0V 

250

600

1000

ms

TD Pin = Open 

500

1200

2000

ms

TD Pin = V

CC 

Note 1:

PB RST must be held low for a minimum of 20 ms to ensure a Reset.

RST

V

IL

t

PB

RST

t

PBD

V

IH

t

RST

PB RST

The debounced PB RST input ignores input pulses less
than 1 ms and is designed to recognize pulses of
20 ms or greater.

t

ST

ST

t

TD

RST (when t

TD

 

 t

TD

 (min)) 

“H”

RST 
(when t

TD

(min) 

 t

TD

 

 t

TD

(max)) 

(when t

TD

 

 t

TD

(max)) 

RST 

RST (when t

TD

 

 t

TD

(min)) 

“L”

RST 
(when t

TD

(min) 

 t

TD

 

 t

TD

(max)) 

(when t

TD

 

 t

TD

(max)) 

RST 

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

 2002-2014 Microchip Technology Inc.

DS20001370E-page 5

TC1232

2.0

TYPICAL PERFORMANCE CURVES

Performance Graphs are not available.

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

TC1232

DS20001370E-page 6

 2002-2014 Microchip Technology Inc.

3.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in 

Table 3-1

.

TABLE 3-1:

PIN FUNCTION TABLES

Pin No.

Symbol

Pin 

Type

Buffer/ 

Driver 

Type

Function

8-pin 

PDIP, 

SOIC

16-pin 

SOIC

1

2

PB RST

I

ST

Push Button Reset Input. 
Input for a Manual Reset Switch. This input debounces (ignores) pulses 
less than 1 ms in duration and is ensured to recognize inputs of 20 ms or 
greater.
L = Manual Reset Switch is Active, Force RST/RST pins Active
H = Manual Reset Switch is Inactive. State of RST/RST pins determined by 
other system conditions. 

2

4

TD

I

ST

Time Delay Input. 
The voltage level on this input determines the Watchdog Timer Time-out 
period. 
TD = 0V

 

 t

TD

 = 150 ms 

TD = Open  

 t

TD

 = 600 ms

TD = V

CC

 

 t

TD

 = 1.2s

3

6

TOL

I

ST

Tolerance Input. 
TOL = GND, Max Voltage Trip Point (V

CCTP

) = 4.75V (5% tolerance)

TOL = V

CC

, Max Voltage Trip Point (V

CCTP

) = 4.5V (10% tolerance)

4

8

GND

P

The ground reference for the device.

5

9

RST

O

Push 

Pull 

Reset Output (Active-High) 
Goes active (High) if one of these conditions occurs:

1.

If V

CC 

falls below the selected Reset voltage threshold.

2.

If PB RST pin is forced low.

3.

If ST pin is not strobed within the minimum selected time-out period. 
(see TD pin)

4.

During power-up.

6

11

RST

O

Open 

Drain 

Reset Output (Active-Low) 
Goes active (Low) if one of these conditions occurs:

1.

If V

CC 

falls below the selected Reset voltage threshold.

2.

If PB RST pin is forced low.

3.

If ST pin is not strobed within the minimum selected time-out period. 
(see TD pin)

4.

During power-up.

7

13

ST

I

ST

Strobe Input
Input for Watchdog Timer. WDT period determined by state of TD pin
Falling Edge 

 Resets Watchdog Timer counter (no time-out)

8

15

V

CC

P

The positive supply (+5V) for the device.

1,3,5,

7,10,1

2,16

NC

No internal connection.

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

 2002-2014 Microchip Technology Inc.

DS20001370E-page 7

TC1232

4.0

OPERATIONAL DESCRIPTION

4.1

Power Monitor

The TC1232 provides the function of warning the
processor of a power failure. When V

CC

 is detected as

being below the voltage levels defined by the TOL pin,
the TC1232’s comparator outputs the RST and RST
signals to a logic level that warns the system of an out-
of-tolerance power supply. The RST and RST signals
switch at a threshold value of 4.5V if TOL is tied to V

CC

,

and at a value of 4.75V if TOL is grounded. The RST
and RST signals are held active for a minimum of
250 ms to ensure that the power supply voltage has
been stabilized. 

Figure 4-1

 shows the V

CC

 fall time. 

Figure 4-2

 shows the V

CC

 rise time. 

Figure 4-3

 shows the time from when the voltage trip

point is detected to the Reset output pin going active.

Figure 4-4

 shows the time from when the voltage trip

point is exited to the Reset output pin going inactive.

FIGURE 4-1:

Power-Down Slew Rate.

FIGURE 4-2:

Power-up Slew Rate.

FIGURE 4-3:

V

CC

 Detect Reset Output 

Delay (Power-Down).

FIGURE 4-4:

V

CC

 Detect Reset Output 

Delay (Power-Up).

+4.75V

t

F

V

CC

+4.25V

t

R

V

CC

+4.25V

+4.75V

V

CC

 = 5V

+4.5V (5% Trip Point)

+4.25V (10% Trip Point)

RST

RST

V

OL

V

OH

 t

RPD

V

CC

 SLEW RATE = 1.66 mV/µs (0.5V/300 µs)

V

CC

4.6V (5% Trip Point)

4.5V(10% Trip Point)

RST

RST

V

OL

V

OH

 t

RPU

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

TC1232

DS20001370E-page 8

 2002-2014 Microchip Technology Inc.

4.2

Push Button Reset Input

The debounced manual Reset input (PB RST) manu-
ally forces the Reset outputs into their active states.

Figure 4-5

 shows a block diagram for using the

TC1232 with a push button switch. 

Once PB RST has been low for a time t

PBD 

(the push

button delay time), the Reset outputs go active. The
Reset outputs remain in their active states for a
minimum of 250 ms after PB RST rises above V

IH

.

Figure 4-6

 shows a waveform for the push button

switch input and the Reset pins output.

A mechanical push button or active logic signal can
drive the PB RST input. The debounced input ignores
input pulses less than 1 ms and recognizes pulses of
20 ms or greater. No external pull-up resistor is
required

 

because the PB RST input has an internal

pull-up to

 

V

CC

 of

 

approximately 100 µA.

FIGURE 4-5:

Push Button Reset and 

Watchdog Timer.

FIGURE 4-6:

Push Button Reset – 

PB RST Input.

V

CC

TOL

PB RST

GND

RST

ST

I/O

Reset

+5V

TC1232

TD

Microprocessor

RST

V

IL

t

PB

RST

t

PBD

V

IH

t

RST

PB RST

The debounced PB RST input ignores input pulses less
than 1 ms and is designed to recognize pulses of
20 ms or greater.

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

 2002-2014 Microchip Technology Inc.

DS20001370E-page 9

TC1232

4.3

Watchdog Timer

When the ST input is not stimulated for a preset time
period, the Watchdog Timer function forces RST and
RST signals to the active state. The preset time period
is determined by the TD inputs to be 150 ms with TD
connected to ground, 600 ms with TD floating or
1200 ms with TD connected to V

CC 

(typ.). The

Watchdog Timer starts timing-out from the set time
period as soon as RST and RST are inactive. If a high-
to-low transition occurs on the ST input pin prior to
time-out, the Watchdog Timer is reset and begins to
time-out again. If the Watchdog Timer is allowed to
time-out, the RST and RST signals are driven to the
active state for 250 ms, minimum (

Figure 4-7

).

The software routine that strobes ST is critical. The
code must be in a section of software that is executed
frequently enough so the time between toggles is less
than the Watchdog Time-out period. One common
technique controls the microprocessor I/O line from two
sections of the program. The software might set the I/O
line high while operating in the Foreground mode and
set it low while in the Background or Interrupt modes. If
both modes do not execute correctly, the Watchdog
Timer issues Reset pulses. 

t

TD

 is the maximum elapsed time between ST high-to-

low transitions (ST is activated by falling edges only),
which will keep the Watchdog Timer from forcing the
Reset outputs active for a time of t

RST

. t

TD

 is a function

of the voltage at the TD pin, as tabulated below:

TABLE 4-1:

WATCHDOG TIMER 
PERIODS

Figure 4-7

 shows a block diagram for using the

TC1232 with a PIC

®

 MCU and the Watchdog input. 

FIGURE 4-7:

Watchdog Timer.

Figure 4-8

 shows the expected Reset output pin wave-

forms depending on the period of the ST pin falling
edge and the state of the TD input pin.

FIGURE 4-8:

Strobe Input.

4.4

Supply Monitor Noise Sensitivity

The TC1232 is optimized for fast response to negative-
going changes in V

DD

. Systems with an inordinate

amount of electrical noise on V

DD

 (such as systems

using relays) may require a 0.01 µF or 0.1 µF bypass
capacitor to reduce detection sensitivity. This capacitor
should be installed as close to the TC1232 as possible
to keep the capacitor lead length short. 

Condition

t

TD

Min.

Typ.

Max.

TD pin = 0V

62.5 ms

150 ms

250 ms

TD pin = Open

250 ms

600 ms

1000 ms

TD pin = V

CC

500 ms

1200 ms

2000 ms

V

CC

TOL GND

RST

ST

RESET

+5V

TC1232

TD

0.1

10 k

 

I/O

PIC

®

3-Terminal

Regulator

+5V

µF

MCU

(example: 

MCP1700)

t

ST

ST

t

TD

RST (when t

TD

 

 t

TD

 (min)) 

“H”

RST 
(when t

TD

(min) 

 t

TD

 

 t

TD

(max)) 

(when t

TD

 

 t

TD

(max)) 

RST 

RST (when t

TD

 

 t

TD

(min)) 

“L”

RST 
(when t

TD

(min) 

 t

TD

 

 t

TD

(max)) 

(when t

TD

 

 t

TD

(max)) 

RST 

/var/www/html/datasheet/sites/default/files/pdfhtml_dummy/20001370E-html.html
background image

TC1232

DS20001370E-page 10

 2002-2014 Microchip Technology Inc.

5.0

PACKAGING INFORMATION

5.1

Package Marking Information

XXXXXXXX
XXXXXNNN

YYWW

8-Lead PDIP (300 mil)

Examples:

8-Lead SOIC (150 mil)

Examples:

XXXXXXXX

XXXXYYWW

NNN

TC1232
I/P256

0518

TC1232

COA0518

256

16-Lead SOIC (150 mil)

Examples:

XXXXXXXXXXXXX

YYWWNNN

XXXXXXXXXXXXX

TC1232COE

0518256

XXXXXXXXXX

Legend: XX...X

Customer-specific information

Y

Year code (last digit of calendar year)

YY

Year code (last 2 digits of calendar year)

WW

Week code (week of January 1 is week ‘01’)

NNN

Alphanumeric traceability code

  

Pb-free JEDEC

®

 designator for Matte Tin (Sn)

*

This package is Pb-free. The Pb-free JEDEC designator (     )
can be found on the outer packaging for this package.

Note:

In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.

3

e

3

e

TC1232
CPA

^^

256

0518

TC1232E

OA

^^

0518

256

TC1232COE

^^

0518256

XXXXXXXXXX

OR

OR

OR

3

e

3

e

3

e

Maker
Microchip Technology Inc.
Datasheet PDF Download