SMSC EMC1203/EMC1204
DATASHEET
Revision 1.1 (06-11-08)
Datasheet
PRODUCT FEATURES
EMC1203/EMC1204
Triple/Quad Single-Wire Temp
Sensor in MSOP-8 Using
SMSC BudgetBus
TM
Sensor
Interface
General Description
The EMC1203 and EMC1204 are temperature sensors
that communicate with a host over a single-wire SMSC
BudgetBus™ Sensor Interface. The EMC1203 has an
internal temperature sensor and monitors up to two
remote diodes. An additional remote diode is added with
the EMC1204 for a total of three remote zones, and both
devices are in a small MSOP-8 package. When used in
combination with an SMSC Super I/O host, such as a
keyboard controller, a complete thermal management
system is created. A power down mode preserves
battery life in portable applications. The internal 11-bit
sigma delta temperature-to-digital converter provides
superb linearity, high accuracy and excellent noise
immunity.
Features
Single-wire SMSC BudgetBus™ Sensor Interface
Low Power, 3.0V to 3.6V Supply
—
< 50uA at 1 conversion per second
—
< 2.5uA in Standby
External Temperature Sensor
—
Range -63.875
º
C to +191.875
º
C
—
0.125
º
C resolution
—
±
1
º
C Accuracy 60
º
C to 100
º
C
—
Diode Fault Reporting
Self Contained Internal Temperature Sensor
—
Range 0
º
C to +85
º
C
—
0.125
º
C resolution
—
±3º C Accuracy 0º C to 85º C
MSOP-8 3x3mm lead-free RoHS compliant packages
Applications
Desktop Computers
Notebook Computers
Server Applications
Simplified Block Diagram
PART
NUMBER
INTERNAL
TEMPERATURE
MONITOR
REMOTE
TEMPERATURE
MONITOR
EMC1203
1
2
EMC1204
1
3
EMC1203/EMC1204
Local Temp
Diode
Switching
Current
Temperature
Registers
BBUS
11-bit
Sigma Delta
ADC
Anal
o
g
M
u
x
DP1
DN1
DP2/DN3
DN2/DP3
BBUS
Interface
ORDER NUMBER(S):
EMC1203-ACZL-TR IN 8 PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
EMC1204-ACZL-TR IN 8 PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
Reel size is 4,000 pieces.
Evaluation Board available upon request. (EVB-KBC1100)
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
2
SMSC EMC1203/EMC1204
DATASHEET
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2008 SMSC or its subsidiaries. All rights reserved.
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient for
construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies. SMSC
reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications
before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses under any patent
rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated
version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors
known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC products are not
designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injury or severe property
damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the customer. Copies of
this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered
trademark of Standard Microsystems Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND ALL WARRANTIES ARISING FROM ANY COURSE
OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL
DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT;
TORT; NEGLIGENCE OF SMSC OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD
TO HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
3
Revision 1.1 (06-11-08)
DATASHEET
Chapter 1 Pin Configuration
Figure 1.1 EMC1203 and EMC1204 Pin Configuration
1.1
Pin Description
Table 1.1 EMC1203 and EMC1204 Pin Description
PIN
PIN NO.
DESCRIPTION
DP1
1
Positive Analog Connection to External Temperature Diode 1
DN1
2
Negative Analog Connection to External Temperature Diode 1
DN2/DP3
3
Negative Analog Connection to External Temperature Diode 2
Positve Analog Connection to External Temperature Diode 3, EMC1204 only
DP2/DN3
4
Positve Analog Connection to External Temperature Diode 2
Negative Analog Connection to External Temperature Diode 3, EMC1204 only
BBUS
5
Serial Bus Interface to BBUS Host
SCLK
6
Normally GND, this pin may be configured to source a synchronous clock.
GND
7
Ground
VDD
8
Supply Voltage V
DD
EMC1203/
EMC1204
TOP VIEW
8
7
6
5
1
2
3
4
DP1
DN1
DN2/DP3
DP2/DN3
VDD
GND
SCLK
BBUS
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
4
SMSC EMC1203/EMC1204
DATASHEET
1.2
Absolute Maximum Ratings
Note: Stresses above those listed could cause damage to the device. This is a stress rating only
and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Table 1.2 EMC1203 and EMC1204 Maximum Ratings
DESCRIPTION
RATING
UNIT
Supply Voltage V
DD
-0.3 to 5.0
V
Voltage on any other pin
-0.3 to V
DD
+0.3
V
Operating Temperature Range
0 to 85
°C
Storage Temperature Range
-55 to 150
°C
Lead Temperature Range
Refer to JEDEC
Spec. J-STD-020
Package Thermal Characteristics for MSOP-8
Power Dissipation
TBD
Thermal Resistance(at 0 air flow)
109.6
°C/W
ESD Rating, All Pins Human Body Model
2000
V
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
5
Revision 1.1 (06-11-08)
DATASHEET
Chapter 2 Electrical Characteristics
Table 2.1 Electrical Characteristics
V
DD
=3.0V to 3.6V, T
A
= 0
°C to +85°C, Typical values at T
A
= 27
°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
DC Power
Supply Voltage
V
DD
3.0
3.3
3.6
V
Average Operating Current
I
DD
600
650
μA
Active mode
(continuous)
I
PD
1.8
2.5
μA
Standby mode
Internal Temperature Measurement
Accuracy
±1
±3
°C
0
°C≤T
A
≤85°C
External Temperature Measurement
Temperature Accuracy
Remote Diode 60
°C to 100°C
Remote Diode 0
°C to 125°C
Remote Diode 0
°C to 125°C
± 1
± 3
TBD
°C
°C
°C
15
°C≤T
A
≤70°C
0
°C≤T
A
≤85°C
-40
°C≤T
A
≤125°C
ADC
Resolution
0.125
°C
Conversion Time per sensor
20
ms
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
6
SMSC EMC1203/EMC1204
DATASHEET
Chapter 3 Product Description
The EMC1203 and EMC1204 are temperature sensors with a proprietary single wire SMSC
BudgetBus™ Sensor Interface. Temperature information is communicated to a host device via the
serial bus. All intelligence regarding the interpretation of temperature resides in the host.
Figure 3.1,
"System Overview"
shows a typical system overview:
Figure 3.1 System Overview
In cooperation with the host device, thermal management can be performed as shown in
Figure 3.1
.
Thermal management consists of the host acquiring the temperature data from the EMC1203 and
EMC1204 controlling the speed of one or more fans. The host has the ability to compare measured
temperature levels to preset limits and take the appropriate action when values are found to be out of
limit. The EMC1203 and the DP1/DN1 port of the EMC1204 are compatible with CPU substrate diodes.
Two separate temperature zones are monitored using only two pins on the EMC1204. This is
accomplished using two anti-parallel diodes as shown on the pins DP2/DN3 and DN2/DP3 in
Figure 3.1
. This technique maintains high accuracy while minimizing pin count and reducing board
routing complexity. The anti-parallel diode architecture performs very well with diode connected
transistors. It is not compatible with substrate transistors (sometimes called thermal diodes or on-chip
sense junctions).
3.1
Temperature Monitors
Thermal diode temperature measurements are based on the change in forward bias voltage (
ΔV
BE
) of
a diode when operated at two different currents:
The change in
Δ
V
BE
voltage is proportional to absolute temperature T.
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
= diode ideality factor
EMC1203/
EMC1204
Host
(KBC1100)
BBUS
Interface
DP1
DN1
DP2/DN3
DN2/DP3
BBUS
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
=
−
=
Δ
LOW
HIGH
LOW
BE
HIGH
BE
BE
I
I
q
kT
V
V
V
ln
_
_
η
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
7
Revision 1.1 (06-11-08)
DATASHEET
Figure 3.2 Detailed Block Diagram of Temperature Monitor Architecture
Figure 3.2
shows a detailed block diagram of the temperature measurement circuit. As shown, the
EMC1203 and EMC1204 incorporates switched capacitor technology that samples the temperature
diode voltage at two bias currents and holds the difference voltage. The sample frequency is 100kHz
and the current levels Ihigh and Ilow are 170uA and 10uA respectively.
The output of the switched capacitor sample and hold circuit interfaces to a single bit delta sigma
analog to digital converter. This ADC runs at 100kHz sample frequency and its output is digitally filtered
and averaged over 2048 samples effectively generating 11 bit accuracy.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta sigma ADC single bit
comparator while the noise immunity is achieved by the digital averaging filter. The overall effective
bandwidth of the system is fs/2048 which translates to a 50Hz bandwidth at 100kHz sample rate.
Conversion time equals about 20ms per temperature monitor.
3.1.1
EMC1203 Temperature Monitoring
The EMC1203, incorporates one internal diode and can monitor two additional temperature zones with
two external diodes.An internal analog multiplexer switches between the internal and external diodes.
Total conversion time for one internal and two external temperature readings is about 60ms. The
external diodes can be either a CPU substrate diode or a discrete diode connected transistor like the
2N3904 or 2N3906. External diode connected transistors examples are shown in
Figure 3.3
:
Figure 3.3 EMC1203 External Diode Examples
3.1.2
EMC1204 Temperature Monitoring
The EMC1204, incorporates one internal diode and can monitor three external diodes. Total conversion
time for one internal and three external temperature reading is 80ms. An internal multiplexer switches
between internal and external diodes. The external thermal diode connected to DP1 and DN1 can
Delta Vbe
Sample
&
Hold
I
bias
I
low
I
high
1-bit
Sigma
Delta
Modulator
Digital
Averaging
Filter
V
DD
Internal
or External
Diode
Bias
Diode
11-bit Output
Local Ground
to
DP
Typical remote
substrate transistor
i.e. CPU substrate PNP
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to
DN
to
DP
to
DN
to
DP
to
DN
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
8
SMSC EMC1203/EMC1204
DATASHEET
either be a CPU substrate diode or a regular thermal diode-connected transistor. External diodes at
DP2/DN3 and DN2/DP3 have to be connected in an anti-parallel fashion. Because of this, one diode
will be forward biased while the other is reverse biased and therefore it is recommended to connect
only discrete thermal diodes to these pins.
Do not use the anti-parallel interface (DP2/DN3 and DN2/DP3) to connect substrate transistors
(sometimes called thermal diodes or on-chip sense junctions). External diode connected transistors
examples are shown in
Figure 3.4
Figure 3.4 EMC1204 External Diode Examples
3.2
SMSC BudgetBus™ Sensor Interface
The EMC1203 and EMC1204 series of temperature monitors communicate with a host controller, such
as the KBC1100, through the SMSC BudgetBus™ Sensor Interface. The BBUS is a single wire serial
communication protocol between the computer host and its peripheral devices. Please refer to the
SMSC BudgetBus™ Sensor Interface Specification for detailed information about the modes of
operation.
3.3
Power Modes
The EMC1203 and EMC1204 have two basic modes of operation:
Standby Mode:
The host can initiate standby mode by actively pulling the BBUS low. When the Host places the device
in standby mode, the device immediately powers down to draw < 2uA of supply current. It will remain
in this state until it is awakened by the host. If the host pulls the BBUS line low while temperature data
is being clocked out, the device will not enter standby mode until completion of the data transfer. After
entering standby mode, the device will remain in this mode until it is forced into active mode by the
host. The transition from standby to active mode occurs when the host is no longer pulling the BBUS
low.
Active Mode:
The host initiates active mode by enabling a weak pull up on the BBUS. In this mode, the EMC1203
and EMC1204 continuously convert temperature data. During the time that the device is actively
converting a temperature, the BBUS is in tri-state mode, and the Host places a weak pull-up on the
bus to prevent it from floating. After a conversion is completed, the device automatically clocks out the
data from the most recent conversion to the host. When the data packet has been entirely clocked out,
the BBUS returns to tri-state mode, and the ADC begins converting the next temperature sample.
While BBUS is in tri-state mode, the host can command the device to standby mode.
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to DP2/DN3
to DN2/DP3
to DP2/DN3
to DN2/DP3
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
9
Revision 1.1 (06-11-08)
DATASHEET
3.4
Temperature Data Format
Temperature readings are coded in 2’s complement format with a -64ºC offset. This format spans from
–63.875ºC to +191.875ºC with 0.125ºC resolution. A temperature measurement outside this range is
reported as either –63.875ºC or +191.875ºC. The host must add 64ºC to calculate the actual
temperature.
Table 3.1
shows example temperature readings and the value that will be reported on the
BBUS.
As shown in
Table 3.1
, 400h is reserved for diode fault signaling which occurs when open or short
conditions are detected between the external DP and DN pins.
3.5
Conversion Rate
The conversion rate can be controlled by the host. This is accomplished by periodically placing the
device in standby as described in
Section 3.3
.
Table 3.1 Temperature Data Format
ACTUAL TEMP.
(ºC)
2’S COMPLEMENT
OF -64ºC OFFSET
HEX
Diode Fault
100 0000 0000
400
-63.875
100 0000 0001
401
-63.000
100 0000 1000
408
-1.000
101 1111 1000
5F8
0.000
110 0000 0000
600
+0.125
110 0000 0001
601
+1.000
110 0000 1000
608
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
10
SMSC EMC1203/EMC1204
DATASHEET
Chapter 4 Package Outline
Figure 4.1 8-Pin MSOP Package Outline - 3x3mm Body 0.65mm Pitch
Notes:
1. Controlling Unit: millimeters.
2. Tolerance on the true position of the leads is ± 0.065 mm maximum.
3. Package body dimensions D and E1 do not include mold protrusion or flash. Dimensions D and
E1 to be determined at datum plane H. Maximum mold protrusion or flash is 0.15mm (0.006 inches)
per end, and 0.15mm (0.006 inches) per side.
4. Dimension for foot length L measured at the gauge plane 0.25 mm above the seating plane.
5. Details of pin 1 identifier are optional but must be located within the zone indicated.
Table 4.1 8-Pin MSOP Package Parameters
MIN
NOMINAL
MAX
REMARKS
A
0.80
~
1.10
Overall Package Height
A1
0.05
~
0.15
Standoff
A2
0.75
0.85
0.95
Body Thickness
D
2.80
3.00
3.20
X Body Size
E
4.65
4.90
5.15
Y Span
E1
2.80
~
3.20
Y body Size
H
0.08
~
0.23
Lead Foot Thickness
L
0.40
~
0.80
Lead Foot Length
L1
0.95 REF
Lead Length
e
0.65 BSC
Lead Pitch
θ
0
o
~
8
o
Lead Foot Angle
W
0.22
~
0.38
Lead Width
ccc
~
~
0.10
Coplanarity
SMSC EMC1203/EMC1204
DATASHEET
Revision 1.1 (06-11-08)
Datasheet
PRODUCT FEATURES
EMC1203/EMC1204
Triple/Quad Single-Wire Temp
Sensor in MSOP-8 Using
SMSC BudgetBus
TM
Sensor
Interface
General Description
The EMC1203 and EMC1204 are temperature sensors
that communicate with a host over a single-wire SMSC
BudgetBus™ Sensor Interface. The EMC1203 has an
internal temperature sensor and monitors up to two
remote diodes. An additional remote diode is added with
the EMC1204 for a total of three remote zones, and both
devices are in a small MSOP-8 package. When used in
combination with an SMSC Super I/O host, such as a
keyboard controller, a complete thermal management
system is created. A power down mode preserves
battery life in portable applications. The internal 11-bit
sigma delta temperature-to-digital converter provides
superb linearity, high accuracy and excellent noise
immunity.
Features
Single-wire SMSC BudgetBus™ Sensor Interface
Low Power, 3.0V to 3.6V Supply
—
< 50uA at 1 conversion per second
—
< 2.5uA in Standby
External Temperature Sensor
—
Range -63.875
º
C to +191.875
º
C
—
0.125
º
C resolution
—
±
1
º
C Accuracy 60
º
C to 100
º
C
—
Diode Fault Reporting
Self Contained Internal Temperature Sensor
—
Range 0
º
C to +85
º
C
—
0.125
º
C resolution
—
±3º C Accuracy 0º C to 85º C
MSOP-8 3x3mm lead-free RoHS compliant packages
Applications
Desktop Computers
Notebook Computers
Server Applications
Simplified Block Diagram
PART
NUMBER
INTERNAL
TEMPERATURE
MONITOR
REMOTE
TEMPERATURE
MONITOR
EMC1203
1
2
EMC1204
1
3
EMC1203/EMC1204
Local Temp
Diode
Switching
Current
Temperature
Registers
BBUS
11-bit
Sigma Delta
ADC
Anal
o
g
M
u
x
DP1
DN1
DP2/DN3
DN2/DP3
BBUS
Interface
ORDER NUMBER(S):
EMC1203-ACZL-TR IN 8 PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
EMC1204-ACZL-TR IN 8 PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
Reel size is 4,000 pieces.
Evaluation Board available upon request. (EVB-KBC1100)
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
2
SMSC EMC1203/EMC1204
DATASHEET
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2008 SMSC or its subsidiaries. All rights reserved.
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient for
construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies. SMSC
reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications
before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses under any patent
rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated
version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors
known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC products are not
designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injury or severe property
damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the customer. Copies of
this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered
trademark of Standard Microsystems Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND ALL WARRANTIES ARISING FROM ANY COURSE
OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL
DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT;
TORT; NEGLIGENCE OF SMSC OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD
TO HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
3
Revision 1.1 (06-11-08)
DATASHEET
Chapter 1 Pin Configuration
Figure 1.1 EMC1203 and EMC1204 Pin Configuration
1.1
Pin Description
Table 1.1 EMC1203 and EMC1204 Pin Description
PIN
PIN NO.
DESCRIPTION
DP1
1
Positive Analog Connection to External Temperature Diode 1
DN1
2
Negative Analog Connection to External Temperature Diode 1
DN2/DP3
3
Negative Analog Connection to External Temperature Diode 2
Positve Analog Connection to External Temperature Diode 3, EMC1204 only
DP2/DN3
4
Positve Analog Connection to External Temperature Diode 2
Negative Analog Connection to External Temperature Diode 3, EMC1204 only
BBUS
5
Serial Bus Interface to BBUS Host
SCLK
6
Normally GND, this pin may be configured to source a synchronous clock.
GND
7
Ground
VDD
8
Supply Voltage V
DD
EMC1203/
EMC1204
TOP VIEW
8
7
6
5
1
2
3
4
DP1
DN1
DN2/DP3
DP2/DN3
VDD
GND
SCLK
BBUS
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
4
SMSC EMC1203/EMC1204
DATASHEET
1.2
Absolute Maximum Ratings
Note: Stresses above those listed could cause damage to the device. This is a stress rating only
and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Table 1.2 EMC1203 and EMC1204 Maximum Ratings
DESCRIPTION
RATING
UNIT
Supply Voltage V
DD
-0.3 to 5.0
V
Voltage on any other pin
-0.3 to V
DD
+0.3
V
Operating Temperature Range
0 to 85
°C
Storage Temperature Range
-55 to 150
°C
Lead Temperature Range
Refer to JEDEC
Spec. J-STD-020
Package Thermal Characteristics for MSOP-8
Power Dissipation
TBD
Thermal Resistance(at 0 air flow)
109.6
°C/W
ESD Rating, All Pins Human Body Model
2000
V
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
5
Revision 1.1 (06-11-08)
DATASHEET
Chapter 2 Electrical Characteristics
Table 2.1 Electrical Characteristics
V
DD
=3.0V to 3.6V, T
A
= 0
°C to +85°C, Typical values at T
A
= 27
°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
DC Power
Supply Voltage
V
DD
3.0
3.3
3.6
V
Average Operating Current
I
DD
600
650
μA
Active mode
(continuous)
I
PD
1.8
2.5
μA
Standby mode
Internal Temperature Measurement
Accuracy
±1
±3
°C
0
°C≤T
A
≤85°C
External Temperature Measurement
Temperature Accuracy
Remote Diode 60
°C to 100°C
Remote Diode 0
°C to 125°C
Remote Diode 0
°C to 125°C
± 1
± 3
TBD
°C
°C
°C
15
°C≤T
A
≤70°C
0
°C≤T
A
≤85°C
-40
°C≤T
A
≤125°C
ADC
Resolution
0.125
°C
Conversion Time per sensor
20
ms
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
6
SMSC EMC1203/EMC1204
DATASHEET
Chapter 3 Product Description
The EMC1203 and EMC1204 are temperature sensors with a proprietary single wire SMSC
BudgetBus™ Sensor Interface. Temperature information is communicated to a host device via the
serial bus. All intelligence regarding the interpretation of temperature resides in the host.
Figure 3.1,
"System Overview"
shows a typical system overview:
Figure 3.1 System Overview
In cooperation with the host device, thermal management can be performed as shown in
Figure 3.1
.
Thermal management consists of the host acquiring the temperature data from the EMC1203 and
EMC1204 controlling the speed of one or more fans. The host has the ability to compare measured
temperature levels to preset limits and take the appropriate action when values are found to be out of
limit. The EMC1203 and the DP1/DN1 port of the EMC1204 are compatible with CPU substrate diodes.
Two separate temperature zones are monitored using only two pins on the EMC1204. This is
accomplished using two anti-parallel diodes as shown on the pins DP2/DN3 and DN2/DP3 in
Figure 3.1
. This technique maintains high accuracy while minimizing pin count and reducing board
routing complexity. The anti-parallel diode architecture performs very well with diode connected
transistors. It is not compatible with substrate transistors (sometimes called thermal diodes or on-chip
sense junctions).
3.1
Temperature Monitors
Thermal diode temperature measurements are based on the change in forward bias voltage (
ΔV
BE
) of
a diode when operated at two different currents:
The change in
Δ
V
BE
voltage is proportional to absolute temperature T.
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
= diode ideality factor
EMC1203/
EMC1204
Host
(KBC1100)
BBUS
Interface
DP1
DN1
DP2/DN3
DN2/DP3
BBUS
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
=
−
=
Δ
LOW
HIGH
LOW
BE
HIGH
BE
BE
I
I
q
kT
V
V
V
ln
_
_
η
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
7
Revision 1.1 (06-11-08)
DATASHEET
Figure 3.2 Detailed Block Diagram of Temperature Monitor Architecture
Figure 3.2
shows a detailed block diagram of the temperature measurement circuit. As shown, the
EMC1203 and EMC1204 incorporates switched capacitor technology that samples the temperature
diode voltage at two bias currents and holds the difference voltage. The sample frequency is 100kHz
and the current levels Ihigh and Ilow are 170uA and 10uA respectively.
The output of the switched capacitor sample and hold circuit interfaces to a single bit delta sigma
analog to digital converter. This ADC runs at 100kHz sample frequency and its output is digitally filtered
and averaged over 2048 samples effectively generating 11 bit accuracy.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta sigma ADC single bit
comparator while the noise immunity is achieved by the digital averaging filter. The overall effective
bandwidth of the system is fs/2048 which translates to a 50Hz bandwidth at 100kHz sample rate.
Conversion time equals about 20ms per temperature monitor.
3.1.1
EMC1203 Temperature Monitoring
The EMC1203, incorporates one internal diode and can monitor two additional temperature zones with
two external diodes.An internal analog multiplexer switches between the internal and external diodes.
Total conversion time for one internal and two external temperature readings is about 60ms. The
external diodes can be either a CPU substrate diode or a discrete diode connected transistor like the
2N3904 or 2N3906. External diode connected transistors examples are shown in
Figure 3.3
:
Figure 3.3 EMC1203 External Diode Examples
3.1.2
EMC1204 Temperature Monitoring
The EMC1204, incorporates one internal diode and can monitor three external diodes. Total conversion
time for one internal and three external temperature reading is 80ms. An internal multiplexer switches
between internal and external diodes. The external thermal diode connected to DP1 and DN1 can
Delta Vbe
Sample
&
Hold
I
bias
I
low
I
high
1-bit
Sigma
Delta
Modulator
Digital
Averaging
Filter
V
DD
Internal
or External
Diode
Bias
Diode
11-bit Output
Local Ground
to
DP
Typical remote
substrate transistor
i.e. CPU substrate PNP
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to
DN
to
DP
to
DN
to
DP
to
DN
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
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SMSC EMC1203/EMC1204
DATASHEET
either be a CPU substrate diode or a regular thermal diode-connected transistor. External diodes at
DP2/DN3 and DN2/DP3 have to be connected in an anti-parallel fashion. Because of this, one diode
will be forward biased while the other is reverse biased and therefore it is recommended to connect
only discrete thermal diodes to these pins.
Do not use the anti-parallel interface (DP2/DN3 and DN2/DP3) to connect substrate transistors
(sometimes called thermal diodes or on-chip sense junctions). External diode connected transistors
examples are shown in
Figure 3.4
Figure 3.4 EMC1204 External Diode Examples
3.2
SMSC BudgetBus™ Sensor Interface
The EMC1203 and EMC1204 series of temperature monitors communicate with a host controller, such
as the KBC1100, through the SMSC BudgetBus™ Sensor Interface. The BBUS is a single wire serial
communication protocol between the computer host and its peripheral devices. Please refer to the
SMSC BudgetBus™ Sensor Interface Specification for detailed information about the modes of
operation.
3.3
Power Modes
The EMC1203 and EMC1204 have two basic modes of operation:
Standby Mode:
The host can initiate standby mode by actively pulling the BBUS low. When the Host places the device
in standby mode, the device immediately powers down to draw < 2uA of supply current. It will remain
in this state until it is awakened by the host. If the host pulls the BBUS line low while temperature data
is being clocked out, the device will not enter standby mode until completion of the data transfer. After
entering standby mode, the device will remain in this mode until it is forced into active mode by the
host. The transition from standby to active mode occurs when the host is no longer pulling the BBUS
low.
Active Mode:
The host initiates active mode by enabling a weak pull up on the BBUS. In this mode, the EMC1203
and EMC1204 continuously convert temperature data. During the time that the device is actively
converting a temperature, the BBUS is in tri-state mode, and the Host places a weak pull-up on the
bus to prevent it from floating. After a conversion is completed, the device automatically clocks out the
data from the most recent conversion to the host. When the data packet has been entirely clocked out,
the BBUS returns to tri-state mode, and the ADC begins converting the next temperature sample.
While BBUS is in tri-state mode, the host can command the device to standby mode.
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to DP2/DN3
to DN2/DP3
to DP2/DN3
to DN2/DP3
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
9
Revision 1.1 (06-11-08)
DATASHEET
3.4
Temperature Data Format
Temperature readings are coded in 2’s complement format with a -64ºC offset. This format spans from
–63.875ºC to +191.875ºC with 0.125ºC resolution. A temperature measurement outside this range is
reported as either –63.875ºC or +191.875ºC. The host must add 64ºC to calculate the actual
temperature.
Table 3.1
shows example temperature readings and the value that will be reported on the
BBUS.
As shown in
Table 3.1
, 400h is reserved for diode fault signaling which occurs when open or short
conditions are detected between the external DP and DN pins.
3.5
Conversion Rate
The conversion rate can be controlled by the host. This is accomplished by periodically placing the
device in standby as described in
Section 3.3
.
Table 3.1 Temperature Data Format
ACTUAL TEMP.
(ºC)
2’S COMPLEMENT
OF -64ºC OFFSET
HEX
Diode Fault
100 0000 0000
400
-63.875
100 0000 0001
401
-63.000
100 0000 1000
408
-1.000
101 1111 1000
5F8
0.000
110 0000 0000
600
+0.125
110 0000 0001
601
+1.000
110 0000 1000
608
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
10
SMSC EMC1203/EMC1204
DATASHEET
Chapter 4 Package Outline
Figure 4.1 8-Pin MSOP Package Outline - 3x3mm Body 0.65mm Pitch
Notes:
1. Controlling Unit: millimeters.
2. Tolerance on the true position of the leads is ± 0.065 mm maximum.
3. Package body dimensions D and E1 do not include mold protrusion or flash. Dimensions D and
E1 to be determined at datum plane H. Maximum mold protrusion or flash is 0.15mm (0.006 inches)
per end, and 0.15mm (0.006 inches) per side.
4. Dimension for foot length L measured at the gauge plane 0.25 mm above the seating plane.
5. Details of pin 1 identifier are optional but must be located within the zone indicated.
Table 4.1 8-Pin MSOP Package Parameters
MIN
NOMINAL
MAX
REMARKS
A
0.80
~
1.10
Overall Package Height
A1
0.05
~
0.15
Standoff
A2
0.75
0.85
0.95
Body Thickness
D
2.80
3.00
3.20
X Body Size
E
4.65
4.90
5.15
Y Span
E1
2.80
~
3.20
Y body Size
H
0.08
~
0.23
Lead Foot Thickness
L
0.40
~
0.80
Lead Foot Length
L1
0.95 REF
Lead Length
e
0.65 BSC
Lead Pitch
θ
0
o
~
8
o
Lead Foot Angle
W
0.22
~
0.38
Lead Width
ccc
~
~
0.10
Coplanarity
SMSC EMC1203/EMC1204
DATASHEET
Revision 1.1 (06-11-08)
Datasheet
PRODUCT FEATURES
EMC1203/EMC1204
Triple/Quad Single-Wire Temp
Sensor in MSOP-8 Using
SMSC BudgetBus
TM
Sensor
Interface
General Description
The EMC1203 and EMC1204 are temperature sensors
that communicate with a host over a single-wire SMSC
BudgetBus™ Sensor Interface. The EMC1203 has an
internal temperature sensor and monitors up to two
remote diodes. An additional remote diode is added with
the EMC1204 for a total of three remote zones, and both
devices are in a small MSOP-8 package. When used in
combination with an SMSC Super I/O host, such as a
keyboard controller, a complete thermal management
system is created. A power down mode preserves
battery life in portable applications. The internal 11-bit
sigma delta temperature-to-digital converter provides
superb linearity, high accuracy and excellent noise
immunity.
Features
Single-wire SMSC BudgetBus™ Sensor Interface
Low Power, 3.0V to 3.6V Supply
—
< 50uA at 1 conversion per second
—
< 2.5uA in Standby
External Temperature Sensor
—
Range -63.875
º
C to +191.875
º
C
—
0.125
º
C resolution
—
±
1
º
C Accuracy 60
º
C to 100
º
C
—
Diode Fault Reporting
Self Contained Internal Temperature Sensor
—
Range 0
º
C to +85
º
C
—
0.125
º
C resolution
—
±3º C Accuracy 0º C to 85º C
MSOP-8 3x3mm lead-free RoHS compliant packages
Applications
Desktop Computers
Notebook Computers
Server Applications
Simplified Block Diagram
PART
NUMBER
INTERNAL
TEMPERATURE
MONITOR
REMOTE
TEMPERATURE
MONITOR
EMC1203
1
2
EMC1204
1
3
EMC1203/EMC1204
Local Temp
Diode
Switching
Current
Temperature
Registers
BBUS
11-bit
Sigma Delta
ADC
Anal
o
g
M
u
x
DP1
DN1
DP2/DN3
DN2/DP3
BBUS
Interface
ORDER NUMBER(S):
EMC1203-ACZL-TR IN 8 PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
EMC1204-ACZL-TR IN 8 PIN, MSOP LEAD-FREE ROHS COMPLIANT PACKAGE
Reel size is 4,000 pieces.
Evaluation Board available upon request. (EVB-KBC1100)
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
2
SMSC EMC1203/EMC1204
DATASHEET
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2008 SMSC or its subsidiaries. All rights reserved.
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient for
construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies. SMSC
reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications
before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses under any patent
rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated
version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors
known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC products are not
designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injury or severe property
damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the customer. Copies of
this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered
trademark of Standard Microsystems Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND ALL WARRANTIES ARISING FROM ANY COURSE
OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL
DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT;
TORT; NEGLIGENCE OF SMSC OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD
TO HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
3
Revision 1.1 (06-11-08)
DATASHEET
Chapter 1 Pin Configuration
Figure 1.1 EMC1203 and EMC1204 Pin Configuration
1.1
Pin Description
Table 1.1 EMC1203 and EMC1204 Pin Description
PIN
PIN NO.
DESCRIPTION
DP1
1
Positive Analog Connection to External Temperature Diode 1
DN1
2
Negative Analog Connection to External Temperature Diode 1
DN2/DP3
3
Negative Analog Connection to External Temperature Diode 2
Positve Analog Connection to External Temperature Diode 3, EMC1204 only
DP2/DN3
4
Positve Analog Connection to External Temperature Diode 2
Negative Analog Connection to External Temperature Diode 3, EMC1204 only
BBUS
5
Serial Bus Interface to BBUS Host
SCLK
6
Normally GND, this pin may be configured to source a synchronous clock.
GND
7
Ground
VDD
8
Supply Voltage V
DD
EMC1203/
EMC1204
TOP VIEW
8
7
6
5
1
2
3
4
DP1
DN1
DN2/DP3
DP2/DN3
VDD
GND
SCLK
BBUS
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
4
SMSC EMC1203/EMC1204
DATASHEET
1.2
Absolute Maximum Ratings
Note: Stresses above those listed could cause damage to the device. This is a stress rating only
and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Table 1.2 EMC1203 and EMC1204 Maximum Ratings
DESCRIPTION
RATING
UNIT
Supply Voltage V
DD
-0.3 to 5.0
V
Voltage on any other pin
-0.3 to V
DD
+0.3
V
Operating Temperature Range
0 to 85
°C
Storage Temperature Range
-55 to 150
°C
Lead Temperature Range
Refer to JEDEC
Spec. J-STD-020
Package Thermal Characteristics for MSOP-8
Power Dissipation
TBD
Thermal Resistance(at 0 air flow)
109.6
°C/W
ESD Rating, All Pins Human Body Model
2000
V
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
5
Revision 1.1 (06-11-08)
DATASHEET
Chapter 2 Electrical Characteristics
Table 2.1 Electrical Characteristics
V
DD
=3.0V to 3.6V, T
A
= 0
°C to +85°C, Typical values at T
A
= 27
°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
DC Power
Supply Voltage
V
DD
3.0
3.3
3.6
V
Average Operating Current
I
DD
600
650
μA
Active mode
(continuous)
I
PD
1.8
2.5
μA
Standby mode
Internal Temperature Measurement
Accuracy
±1
±3
°C
0
°C≤T
A
≤85°C
External Temperature Measurement
Temperature Accuracy
Remote Diode 60
°C to 100°C
Remote Diode 0
°C to 125°C
Remote Diode 0
°C to 125°C
± 1
± 3
TBD
°C
°C
°C
15
°C≤T
A
≤70°C
0
°C≤T
A
≤85°C
-40
°C≤T
A
≤125°C
ADC
Resolution
0.125
°C
Conversion Time per sensor
20
ms
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
6
SMSC EMC1203/EMC1204
DATASHEET
Chapter 3 Product Description
The EMC1203 and EMC1204 are temperature sensors with a proprietary single wire SMSC
BudgetBus™ Sensor Interface. Temperature information is communicated to a host device via the
serial bus. All intelligence regarding the interpretation of temperature resides in the host.
Figure 3.1,
"System Overview"
shows a typical system overview:
Figure 3.1 System Overview
In cooperation with the host device, thermal management can be performed as shown in
Figure 3.1
.
Thermal management consists of the host acquiring the temperature data from the EMC1203 and
EMC1204 controlling the speed of one or more fans. The host has the ability to compare measured
temperature levels to preset limits and take the appropriate action when values are found to be out of
limit. The EMC1203 and the DP1/DN1 port of the EMC1204 are compatible with CPU substrate diodes.
Two separate temperature zones are monitored using only two pins on the EMC1204. This is
accomplished using two anti-parallel diodes as shown on the pins DP2/DN3 and DN2/DP3 in
Figure 3.1
. This technique maintains high accuracy while minimizing pin count and reducing board
routing complexity. The anti-parallel diode architecture performs very well with diode connected
transistors. It is not compatible with substrate transistors (sometimes called thermal diodes or on-chip
sense junctions).
3.1
Temperature Monitors
Thermal diode temperature measurements are based on the change in forward bias voltage (
ΔV
BE
) of
a diode when operated at two different currents:
The change in
Δ
V
BE
voltage is proportional to absolute temperature T.
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
= diode ideality factor
EMC1203/
EMC1204
Host
(KBC1100)
BBUS
Interface
DP1
DN1
DP2/DN3
DN2/DP3
BBUS
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
=
−
=
Δ
LOW
HIGH
LOW
BE
HIGH
BE
BE
I
I
q
kT
V
V
V
ln
_
_
η
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
7
Revision 1.1 (06-11-08)
DATASHEET
Figure 3.2 Detailed Block Diagram of Temperature Monitor Architecture
Figure 3.2
shows a detailed block diagram of the temperature measurement circuit. As shown, the
EMC1203 and EMC1204 incorporates switched capacitor technology that samples the temperature
diode voltage at two bias currents and holds the difference voltage. The sample frequency is 100kHz
and the current levels Ihigh and Ilow are 170uA and 10uA respectively.
The output of the switched capacitor sample and hold circuit interfaces to a single bit delta sigma
analog to digital converter. This ADC runs at 100kHz sample frequency and its output is digitally filtered
and averaged over 2048 samples effectively generating 11 bit accuracy.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta sigma ADC single bit
comparator while the noise immunity is achieved by the digital averaging filter. The overall effective
bandwidth of the system is fs/2048 which translates to a 50Hz bandwidth at 100kHz sample rate.
Conversion time equals about 20ms per temperature monitor.
3.1.1
EMC1203 Temperature Monitoring
The EMC1203, incorporates one internal diode and can monitor two additional temperature zones with
two external diodes.An internal analog multiplexer switches between the internal and external diodes.
Total conversion time for one internal and two external temperature readings is about 60ms. The
external diodes can be either a CPU substrate diode or a discrete diode connected transistor like the
2N3904 or 2N3906. External diode connected transistors examples are shown in
Figure 3.3
:
Figure 3.3 EMC1203 External Diode Examples
3.1.2
EMC1204 Temperature Monitoring
The EMC1204, incorporates one internal diode and can monitor three external diodes. Total conversion
time for one internal and three external temperature reading is 80ms. An internal multiplexer switches
between internal and external diodes. The external thermal diode connected to DP1 and DN1 can
Delta Vbe
Sample
&
Hold
I
bias
I
low
I
high
1-bit
Sigma
Delta
Modulator
Digital
Averaging
Filter
V
DD
Internal
or External
Diode
Bias
Diode
11-bit Output
Local Ground
to
DP
Typical remote
substrate transistor
i.e. CPU substrate PNP
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to
DN
to
DP
to
DN
to
DP
to
DN
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
8
SMSC EMC1203/EMC1204
DATASHEET
either be a CPU substrate diode or a regular thermal diode-connected transistor. External diodes at
DP2/DN3 and DN2/DP3 have to be connected in an anti-parallel fashion. Because of this, one diode
will be forward biased while the other is reverse biased and therefore it is recommended to connect
only discrete thermal diodes to these pins.
Do not use the anti-parallel interface (DP2/DN3 and DN2/DP3) to connect substrate transistors
(sometimes called thermal diodes or on-chip sense junctions). External diode connected transistors
examples are shown in
Figure 3.4
Figure 3.4 EMC1204 External Diode Examples
3.2
SMSC BudgetBus™ Sensor Interface
The EMC1203 and EMC1204 series of temperature monitors communicate with a host controller, such
as the KBC1100, through the SMSC BudgetBus™ Sensor Interface. The BBUS is a single wire serial
communication protocol between the computer host and its peripheral devices. Please refer to the
SMSC BudgetBus™ Sensor Interface Specification for detailed information about the modes of
operation.
3.3
Power Modes
The EMC1203 and EMC1204 have two basic modes of operation:
Standby Mode:
The host can initiate standby mode by actively pulling the BBUS low. When the Host places the device
in standby mode, the device immediately powers down to draw < 2uA of supply current. It will remain
in this state until it is awakened by the host. If the host pulls the BBUS line low while temperature data
is being clocked out, the device will not enter standby mode until completion of the data transfer. After
entering standby mode, the device will remain in this mode until it is forced into active mode by the
host. The transition from standby to active mode occurs when the host is no longer pulling the BBUS
low.
Active Mode:
The host initiates active mode by enabling a weak pull up on the BBUS. In this mode, the EMC1203
and EMC1204 continuously convert temperature data. During the time that the device is actively
converting a temperature, the BBUS is in tri-state mode, and the Host places a weak pull-up on the
bus to prevent it from floating. After a conversion is completed, the device automatically clocks out the
data from the most recent conversion to the host. When the data packet has been entirely clocked out,
the BBUS returns to tri-state mode, and the ADC begins converting the next temperature sample.
While BBUS is in tri-state mode, the host can command the device to standby mode.
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to DP2/DN3
to DN2/DP3
to DP2/DN3
to DN2/DP3
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1203/EMC1204
9
Revision 1.1 (06-11-08)
DATASHEET
3.4
Temperature Data Format
Temperature readings are coded in 2’s complement format with a -64ºC offset. This format spans from
–63.875ºC to +191.875ºC with 0.125ºC resolution. A temperature measurement outside this range is
reported as either –63.875ºC or +191.875ºC. The host must add 64ºC to calculate the actual
temperature.
Table 3.1
shows example temperature readings and the value that will be reported on the
BBUS.
As shown in
Table 3.1
, 400h is reserved for diode fault signaling which occurs when open or short
conditions are detected between the external DP and DN pins.
3.5
Conversion Rate
The conversion rate can be controlled by the host. This is accomplished by periodically placing the
device in standby as described in
Section 3.3
.
Table 3.1 Temperature Data Format
ACTUAL TEMP.
(ºC)
2’S COMPLEMENT
OF -64ºC OFFSET
HEX
Diode Fault
100 0000 0000
400
-63.875
100 0000 0001
401
-63.000
100 0000 1000
408
-1.000
101 1111 1000
5F8
0.000
110 0000 0000
600
+0.125
110 0000 0001
601
+1.000
110 0000 1000
608
Triple/Quad Single-Wire Temp Sensor in MSOP-8 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.1 (06-11-08)
10
SMSC EMC1203/EMC1204
DATASHEET
Chapter 4 Package Outline
Figure 4.1 8-Pin MSOP Package Outline - 3x3mm Body 0.65mm Pitch
Notes:
1. Controlling Unit: millimeters.
2. Tolerance on the true position of the leads is ± 0.065 mm maximum.
3. Package body dimensions D and E1 do not include mold protrusion or flash. Dimensions D and
E1 to be determined at datum plane H. Maximum mold protrusion or flash is 0.15mm (0.006 inches)
per end, and 0.15mm (0.006 inches) per side.
4. Dimension for foot length L measured at the gauge plane 0.25 mm above the seating plane.
5. Details of pin 1 identifier are optional but must be located within the zone indicated.
Table 4.1 8-Pin MSOP Package Parameters
MIN
NOMINAL
MAX
REMARKS
A
0.80
~
1.10
Overall Package Height
A1
0.05
~
0.15
Standoff
A2
0.75
0.85
0.95
Body Thickness
D
2.80
3.00
3.20
X Body Size
E
4.65
4.90
5.15
Y Span
E1
2.80
~
3.20
Y body Size
H
0.08
~
0.23
Lead Foot Thickness
L
0.40
~
0.80
Lead Foot Length
L1
0.95 REF
Lead Length
e
0.65 BSC
Lead Pitch
θ
0
o
~
8
o
Lead Foot Angle
W
0.22
~
0.38
Lead Width
ccc
~
~
0.10
Coplanarity