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LM95214
SNIS146B – MARCH 2007 – REVISED OCTOBER 2017
LM95214 Quad Remote Diode and Local Temperature Sensor With SMBus Interface
1 Features
3 Description
•
The LM95214 device is an 11-bit digital temperature
sensor with a 2-wire System Management Bus
(SMBus) interface that can very accurately monitor
the temperature of four remote diodes as well as its
own temperature. The four remote diodes can be
external devices such as microprocessors, graphics
processors that target the ideality of a 2N3904
transistor or diode-connected 2N3904s.
1
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Accurately Senses Die Temperature of 4 Remote
ICs or Diode Junctions and Local Temperature
Local Temperature Accuracy ±2.0°C (Maximum)
Remote Diode Temperature Accuracy ±1.1°C
(Maximum)
Supply Voltage: 3 V to 3.6 V
Average Supply Current (1-Hz Conversion Rate)
0.57 mA (Typical)
Programmable Digital Filters and Analog FrontEnd Filter
0.125°C LSB Temperature Resolution
0.03125°C LSB Remote Temperature Resolution
With Digital Filter Enabled
Signed Format: +127.875°C/–128°C Remote
Range
Unsigned Format: 0°C/255°C Remote Range
Remote Diode Fault Detection, Model Selection,
and Offset Correction
Mask and Status Register Support
3 Programmable TCRIT Outputs With
Programmable Shared Hysteresis and FaultQueue
Programmable Conversion Rate and Shutdown
Mode One-Shot Conversion Control
SMBus 2.0 Compatible Interface, Supports
TIMEOUT
Three-Level Address Pin
The LM95214 reports temperature in two different
formats for +127.875°C/–128°C range and 0°C/255°C
range. The LM95214 TCRIT1, TCRIT2 and TCRIT3
outputs are triggered when any unmasked channel
exceeds its corresponding programmable limit and
can be used to shutdown the system, to turn on the
system fans or as a microcontroller interrupt function.
The current status of the TCRIT1, TCRIT2, and
TCRIT3 pins can be read back from the status
registers. Mask registers are available for further
control of the TCRIT outputs.
Two LM95214 remote temperature channels have
programmable digital filters while the other two
remote channels use a fault-queue to minimize
unwanted TCRIT events when temperature spikes
are encountered.
For optimum flexibility and accuracy, each LM95214
channel includes registers for offset correction. A
three-level address pin allows connection of up to 3
LM95214s to the same SMBus master. The LM95214
includes power saving functions such as:
programmable conversion rate, shutdown mode, and
disabling of unused channels.
Device Information(1)
2 Applications
•
•
•
•
•
•
•
•
•
•
MCU, GPU, ASIC, FPGA, DSP, and CPU
Temperature Monitoring
Telecommunication Equipment
Servers and Personal Computers
Cloud Ethernet Switches
Secure Data Centers
Highly Integrated Medical Systems
Precision Instruments and Test Equipment
LED Lighting Thermal Control
Office Electronics
Electronic Test Equipment
Processor and Computer System Thermal
Management
PART NUMBER
LM95214
PACKAGE
WSON (14)
BODY SIZE (NOM)
4.00 mm × 4.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Remote 1 Temperature Error, TA=TD
1.25
3.0V
3.3V
3.6V
1
Temperature Error (°C)
•
0.75
0.5
0.25
0
-0.25
-50
-30
-10
10
30
50
70
Temperature (°C)
90
110
130
D003
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM95214
SNIS146B – MARCH 2007 – REVISED OCTOBER 2017
www.ti.com
Table of Contents
1
2
3
4
5
6
1
1
1
2
3
4
8
6.1
6.2
6.3
6.4
6.5
4
4
5
5
9 Power Supply Recommendations...................... 42
10 Layout................................................................... 43
5
11 Device and Documentation Support ................. 44
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics: Temperature-to-Digital
Converter ..................................................................
6.6 Logic Electrical Characteristics: Digital DC
Characteristics ...........................................................
6.7 Switching Characteristics: SMBus Digital .................
6.8 Typical Characteristics ..............................................
7
7.3 Feature Description................................................. 11
7.4 Device Functional Modes........................................ 20
7.5 Register Maps ......................................................... 23
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
6
7
8
Detailed Description ............................................ 10
7.1 Overview ................................................................. 10
7.2 Functional Block Diagram ....................................... 10
Application and Implementation ........................ 38
8.1 Application Information............................................ 38
8.2 Typical Application .................................................. 38
8.3 Diode Non-Ideality................................................... 39
10.1 Layout Guidelines ................................................. 43
10.2 Layout Example .................................................... 43
11.1
11.2
11.3
11.4
11.5
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
44
44
44
44
44
12 Mechanical, Packaging, and Orderable
Information ........................................................... 44
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision A (March 2013) to Revision B
•
Added Device Information table, Added ESD Ratings table, Feature Description section, Device Functional Modes
section, Application and Implementation section, Specification section, Detailed Description section, Layout section,
Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section. .................. 1
Changes from Original (March 2013) to Revision A
•
2
Page
Page
Changed layout of National Data Sheet to TI format ........................................................................................................... 43
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SNIS146B – MARCH 2007 – REVISED OCTOBER 2017
5 Pin Configuration and Functions
NHL Package
14-Pin WSON
Top View
NC
1
14
TCRIT3
VDD
2
13
SMBCLK
D4+
3
12
SMBDAT
D3+
4
D-
LM95214
11
TCRIT2
5
10
TCRIT1
D2+
6
9
A0
D1+
7
8
GND
Pin Functions
PIN
NO.
DESCRIPTION
NAME
1
NC
No Connect
Not connected. May be left floating, connected to GND or VDD.
2
VDD
Positive Supply Voltage Input
DC Voltage from 3.0 V to 3.6 V. VDD must be bypassed with a 0.1-µF capacitor in parallel with 100 pF. The 100pF capacitor must be placed as close as possible to the power supply pin. Noise must be kept below 200 mVp-p,
a 10-µF capacitor may be required to achieve this.
D4+
Diode Current Source
Fourth Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diodeconnected transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required
between D4+ and D–. A 100 pF capacitor between D4+ and D– can be added and may improve performance in
noisy systems. Float this pin if this thermal diode is not used.
4
D3+
Diode Current Source
Third Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diode-connected
transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required between
D3+ and D–. A 100-pF capacitor between D3+ and D– can be added and may improve performance in noisy
systems. Float this pin if this thermal diode is not used.
5
D−
Diode Return Current Sink
All Diode Cathodes. Common D– pin for all four remote diodes.
D2+
Diode Current Source
Second Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diodeconnected transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required
between D2+ and D–. A 100-pF capacitor between D2+ and D– can be added and may improve performance in
noisy systems. Float this pin if this thermal diode is not used.
7
D1+
Diode Current Source
First Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diode-connected
transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required between
D1+ and D–. A 100-pF capacitor between D1+ and D– can be added and may improve performance in noisy
systems. Float this pin if this thermal diode is not used.
8
GND
Power Supply Ground -- System low noise ground.
9
A0
10
TCRIT1
Digital Output, Open-Drain
Critical temperature output 1. Requires pullup resistor. Active LOW.
11
TCRIT2
Digital Output, Open-Drain
Critical temperature output 2. Requires pullup resistor. Active LOW.
12
SMBDAT
SMBus Bidirectional Data Line, Open-Drain Output
From and to Controller; may require an external pullup resistor
13
SMBCLK
SMBus Clock Input
From Controller; may require an external pullup resistor
14
TCRIT3
3
6
Digital Input
SMBus slave address select pin. Selects one of three addresses. Can be tied to VDD, GND, or to the middle of a
resistor divider connected between VDD and GND.
Digital Output, Open-Drain
Critical temperature output 3. Requires pullup resistor. Active LOW.
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SNIS146B – MARCH 2007 – REVISED OCTOBER 2017
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Table 1. ESD Protection
PIN NO.
LABEL
CIRCUIT
1
NC
–
2
VDD
A
3
D4+
A
4
D3+
A
5
D-
A
6
D2+
A
7
D1+
A
8
GND
–
9
A0
B
10
TCRIT1
B
11
TCRIT2
B
12
SMBDAT
B
13
SMBCLK
B
14
TCRIT2
B
CIRCUITS FOR PIN ESD PROTECTION STRUCTURE
V+
D2
PIN
D1
D3
6.5V
ESD
CLAMP
GND
Circuit A
PIN
D1
SNP
GND
Circuit B
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1) (2) (3)
MIN
MAX
UNIT
Supply voltage
–0.3
6
V
Voltage at SMBDAT, SMBCLK,
TCRIT1, TCRIT2, TCRIT3
–0.5
6
V
Voltage at other pins
–0.3
VDD + 0.3
V
±1
mA
±5
mA
30
mA
10
mA
150
°C
D− Input current
Input current at all other pins
Package input current
(4)
(4)
SMBDAT, TCRIT1, TCRIT2,
TCRIT3 output sink current
Storage temperature, Tstg
(1)
(2)
(3)
(4)
–65
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Soldering process must comply with reflow temperature profile specifications. Refer to http://www.ti.com/packaging
Reflow temperature profiles are different for packages containing lead (Pb) than for those that do not.
When the input voltage (VI) at any pin exceeds the power supplies (VI < GND or VI > VDD), the current at that pin must be limited to 5
mA. Parasitic components and or ESD protection circuitry are shown in the table below for the LM95214's pins.
6.2 ESD Ratings
VALUE
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001
V(ESD)
Electrostatic discharge (1) Charged-device model (CDM), per JEDEC specification JESD22-C101 (3)
Machine Model
(1)
(2)
(3)
4
(2)
UNIT
±2000
±1000
V
±200
Human-body model, 100-pF discharged through a 1.5-kΩ resistor. Machine model, 200-pF discharged directly into each pin. Chargeddevice model (CDM) simulates a pin slowly acquiring charge (such as from a device sliding down the feeder in an automated
assembler) then rapidly being discharged.
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
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6.3 Recommended Operating Conditions
MIN
Operating temperature
MAX
UNIT
–40
140
°C
3
3.6
V
Supply voltage (VDD)
NOM
6.4 Thermal Information
LM95214
THERMAL METRIC (1)
NHL (WSON)
UNIT
14 PINS
RθJA
Junction-to-ambient thermal resistance
38.7
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
27.5
°C/W
RθJB
Junction-to-board thermal resistance
16.7
°C/W
ψJT
Junction-to-top characterization parameter
0.3
°C/W
ψJB
Junction-to-board characterization parameter
16.6
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
3.2
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
6.5 Electrical Characteristics: Temperature-to-Digital Converter
minimum and maximum specifications are over –40°C to +125°C and V+ = +3 V to 3.6 V (unless otherwise noted); typical
specifications are at TA = TJ = 25°C and V+ = 3.3 V
PARAMETER
Temperature error using local diode
Temperature error using an MMBT3904
transistor remote diode (2)
TEST CONDITIONS
TA = –40°C to +125°C,
(1)
(3)
(4)
+2
°C
–1.3
+1.3
°C
TA = –40°C to +85°C
TD = –40°C to +125°C
–3
+3
°C
TA = –40°C to +85°C
TD = 125°C to +140°C
–3.3
+3.3
°C
11
Bits
0.125
°C
11
Bits
0.125
°C
13
Bits
0.03125
°C
1100
1210
ms
1 external channel
31
34
ms
Local only
30
33
ms
SMBus inactive, 1-Hz conversion rate, channels in
default state
570
800
µA
Shutdown
360
High level
160
Low level
10
D− Source voltage
(2)
±1
TA = +25°C to +85°C
TD = –40°C to +125°C
All channels are enabled in default state
(1)
–2
°C
Digital filter on (Remote Diodes 1 and 2 only)
Remote diode source current
UNIT
+1.1
Remote diode measurement resolution
(4)
MAX
–1.1
Digital filter off
Quiescent current
TYP
TA = +25°C to +85°C
TD = +60°C to +100°C
Local diode measurement resolution
Conversion time of all temperatures at
the fastest setting (3)
MIN
µA
0.4
V
230
µA
Local temperature accuracy does not include the effects of self-heating. The rise in temperature due to self-heating is the product of the
internal power dissipation of the LM95214 and the thermal resistance. See under Recommended Operating Conditions table for the
thermal resistance to be used in the self-heating calculation.
The accuracy of the LM95214CISD is ensured when using a typical MMBT3904 diode-connected transistor. For further information on
other thermal diodes see applications Diode Non-Ideality.
This specification is provided only to indicate how often temperature data is updated. The LM95214 can be read at any time without
regard to conversion state (and will yield last conversion result).
Quiescent current will not increase substantially with an SMBus communication.
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Electrical Characteristics: Temperature-to-Digital Converter (continued)
minimum and maximum specifications are over –40°C to +125°C and V+ = +3 V to 3.6 V (unless otherwise noted); typical
specifications are at TA = TJ = 25°C and V+ = 3.3 V
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
Measured on VDD input, falling edge
1.6
TCRIT1 pin temperature threshold
Default diodes 1 and 2 only
110
°C
TCRIT2 pin temperature threshold
Default all channels
85
°C
TCRIT3 pin temperature threshold
Default diodes 3 and 4 only
85
°C
6.6
2.8
UNIT
Power-On reset threshold
V
Logic Electrical Characteristics: Digital DC Characteristics
Unless otherwise noted all limits are specified for VDD = +3 Vdc to 3.6 Vdc, TA= TJ = +25°C.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
SMBDAT, SMBCLK INPUTS
VIN(1)
Logical 1 input voltage
2.1
V
VIN(0)
Logical 0 input voltage
VIN(HYST)
SMBDAT and SMBCLK digital
input hysteresis
IIN(1)
Logical 1 input current
VIN = VDD
0.005
10
µA
IIN(0)
Logical 0 input current
VIN = 0 V
−0.005
–10
µA
CIN
Input capacitance
0.8
400
V
mV
5
pF
0.90 ×
VDD
V
A0 DIGITAL INPUT
VIH
Input high voltage
VIM
Input middle voltage
0.43 ×
VDD
0.57 ×
VDD
V
V
0.10 ×
VDD
V
VIL
Input low voltage
IIN(1)
Logical 1 input current
VIN = VDD
VIN = VDD
–0.005
–10
µA
IIN(0)
Logical 0 input current
VIN = 0 V
VIN = 0 V
0.005
10
µA
CIN
Input capacitance
5
pF
SMBDAT, TCRIT1, TCRIT2, TCRIT3 DIGITAL OUTPUTS
IOH
High level output current
VOL(SMBDAT)
SMBus low level output voltage
VOL(TCRIT)
TCRIT1, TCRIT2, TCRIT3 low
level output voltage
COUT
Digital output capacitance
6
VOH = VDD
IOL = 4 mA
10
0.4
µA
V
IOL = 6 mA
0.6
V
IOL = 6 mA
0.4
V
5
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6.7 Switching Characteristics: SMBus Digital
Unless otherwise noted, these specifications apply for VDD=+3.0 Vdc to +3.6 Vdc, CL (load capacitance) on output lines = 80
pF, TA = TJ = +25°C.
The switching characteristics of the LM95214 fully meet or exceed the published specifications of the SMBus version 2.0. The
following parameters are the timing relationships between SMBCLK and SMBDAT signals related to the LM95214. They
adhere to but are not necessarily the SMBus bus specifications.
PARAMETER
fSMB
TEST CONDITIONS
MIN
SMBus clock frequency
TYP
10
tLOW
SMBus clock low time
from VIN(0)max to VIN(0)max
tHIGH
SMBus clock high time
from VIN(1)min to VIN(1)min
MAX
UNIT
100
kHz
25
ms
4.7
µs
4.0
µs
1
µs
0.3
µs
tR,SMB
SMBus rise time
See
(1)
tF,SMB
SMBus fall time
See
(2)
tOF
Output fall time
CL = 400 pF,
IO = 3 mA (2)
tTIMEOUT
SMBDAT and SMBCLK time
low for reset of serial
interface
tSU;DAT
Data in setup time to
SMBCLK high
250
tHD;DAT
Data out stable after
SMBCLK low
300
tHD;STA
Start condition SMBDAT low
to SMBCLK low (Start
condition hold before the first
clock falling edge)
100
ns
tSU;STO
Stop condition SMBCLK high
to SMBDAT low (Stop
condition setup)
100
ns
tSU;STA
SMBus repeated startcondition setup time,
SMBCLK high to SMBDAT
low
0.6
µs
tBUF
SMBus free time between
stop and start conditions
1.3
µs
(1)
(2)
25
250
ns
35
ms
ns
1075
ns
The output rise time is measured from (VIN(0)max − 0.15 V) to (VIN(1)min + 0.15 V).
The output fall time is measured from (VIN(1)min + 0.15 V) to (VIN(0)max − 0.15 V).
tLOW
tR
SMBCL
K
VIL
tBUF
SMBDA
T
tF
VIH
tHD;STA
tHIGH
tHD;DAT
tSU;STA
tSU;DAT
tSU;STO
VIH
VIL
P
S
P
Figure 1. SMBus Communication
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6.8 Typical Characteristics
3.0
VDD = +3.3V
AVERAGE I DD (mA)
2.5
TA = 25°C
2.0
1.5
1.0
0.5
0.0
100
1000
10000
CONVERSION TIME (ms)
Figure 3. Thermal Diode Capacitor or PCB Leakage Current
Effect on Remote Diode Temperature Reading
Figure 2. Conversion Rate Effect on Average Power Supply
Current
1.25
3.0V
3.3V
3.6V
Temperature Error (°C)
1
0.75
0.5
0.25
0
-0.25
-50
1.25
10
30
50
70
Temperature (°C)
90
110
130
D002
1.25
3.0V
3.3V
3.6V
3.0V
3.3V
3.6V
1
Temperature Error (°C)
1
Temperature Error (°C)
-10
Figure 5. Local Temperature Error, TA = TD
Figure 4. Remote Temperature Reading Sensitivity to
Thermal Diode Filter Capacitance
0.75
0.5
0.25
0
0.75
0.5
0.25
0
-0.25
-50
-30
-10
10
30
50
70
Temperature (°C)
90
110
130
-0.25
-50
D003
Figure 6. Remote 1 Temperature Error, TA = TD
8
-30
-30
-10
10
30
50
70
Temperature (°C)
90
110
130
D001
Figure 7. Remote 2 Temperature Error, TA = TD
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Typical Characteristics (continued)
1.25
1.25
3.0V
3.3V
3.6V
1
Temperature Error (°C)
Temperature Error (°C)
1
3.0V
3.3V
3.6V
0.75
0.5
0.25
0
0.75
0.5
0.25
0
-0.25
-50
-30
-10
10
30
50
70
Temperature (°C)
90
110
130
-0.25
-50
D004
Figure 8. Remote 3 Temperature Error, TA = TD
-30
-10
10
30
50
70
Temperature (°C)
90
110
130
D005
Figure 9. Remote 4 Temperature Error, TA = TD
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7 Detailed Description
7.1 Overview
The LM95214 is an 11-bit digital temperature sensor with a 2-wire System Management Bus (SMBus) interface
that can monitor the temperature of four remote diodes as well as its own temperature. The LM95214 can be
used to very accurately monitor the temperature of up to four external devices such as microprocessors, graphics
processors or diode-connected 2N3904 transistor. Any device whose thermal diode can be modeled by an
MMBT3904 transistor will work well with the LM95214.
The LM95214 reports temperature in two different formats for +127.875°C/–128°C range and 0°C/255°C range.
The LM95214 has a Sigma-Delta ADC (Analog-to-Digital Converter) core which provides the first level of noise
immunity. For improved performance in a noisy environment the LM95214 includes programmable digital filters
for Remote Diode 1 and 2 temperature readings. When the digital filters are invoked the resolution for Remote
Diode 1 and 2 readings increases to 0.03125°C. For maximum flexibility and best accuracy the LM95214
includes offset registers that allow calibration of other diode types.
7.2 Functional Block Diagram
3.0V-3.6V
LM95214
Local
Diode
Selector
D1+
Remote
Diode1
Selector
D2+
Remote
Diode2
Selector
D3+
D4+
Remote
Diode3
Selector
Remote
Diode4
Selector
D-
'-6 Converter
11-Bit or
10-Bit Plus Sign
Remote
10-bit Plus Sign
Local
Local
Temperature
Registers
Temperature
Sensor
Circuitry
Remote 1
Temperature
Registers
Remote 1
Digital Filter
Remote 2
Temperature
Registers
Remote 1
Offset Register
Remote 3
Temperature
Registers
Remote 2
Digital Filter
TCRIT2
T_CRIT
Control
Logic
TCRIT3
Remote 4
Temperature
Registers
Remote 2
Offset Register
Limit,
Status
and
Mask
Registers
Remote 3
Status
Fault Queue
Remote 3
Offset Register
Remote 4
Status
Fault Queue
SMBus
Interface
Remote 4
Offset Register
Control Logic
TCRIT1
SMBDAT
SMBCLK
Conversion
Rate Rgister
Diode
Configuration
Registers
General
Configuration
Registers
10
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7.3 Feature Description
The LM95214 TCRIT1, TCRIT2, and TCRIT3 active low outputs are triggered when any unmasked channel
exceeds its corresponding programmable limit and can be used to shutdown the system, to turn on the system
fans or as a microcontroller interrupt function. The current status of the TCRIT1, TCRIT2, and TCRIT3 pins can
be read back from the status registers through the SMBus interface. Two of the remote channels have two
separate limits each that control the TCRIT1 and TCRIT2 pins. The remaining two channels and the local
channel each have one limit to control both the TCRIT1 and TCRIT2 pins. The TCRIT3 pin shares the limits of
the TCRIT2 pin but allows for different masking options. All limits have a shared programmable hysteresis
register.
Diode fault detection circuitry in the LM95214 can detect the absence or fault state of a remote diode: whether
D+ is shorted to VDD, D– or ground, or whether D+ is floating.
Remote Diode 1 and 2 temperature channels have programmable digital filters while the other two remote
temperature channels utilize a fault-queue to avoid false triggering the TCRIT pins.
The LM95214 has a three-level address pin to connect up to 3 devices to the same SMBus master. LM95214
also has programmable conversion rate register as well as a shutdown mode for power savings. One round of
conversions can be triggered in shutdown mode by writing to the one-shot register through the SMBus interface.
LM95214 can be programmed to turn off unused channels for more power savings.
The LM95214 register set has an 8-bit data structure and includes:
1. Temperature Value Registers with signed format
– Most-Significant-Byte (MSB) and Least-Significant-Byte (LSB) Local Temperature
– MSB and LSB Remote Temperature 1
– MSB and LSB Remote Temperature 2
– MSB and LSB Remote Temperature 3
– MSB and LSB Remote Temperature 4
2. Temperature Value Registers with unsigned format
– MSB and LSB Remote Temperature 1
– MSB and LSB Remote Temperature 2
– MSB and LSB Remote Temperature 3
– MSB and LSB Remote Temperature 4
3. Diode Configuration Registers
– Diode Model Select
– Remote 1 Offset
– Remote 2 Offset
– Remote 3 Offset
– Remote 4 Offset
4. General Configuration Registers
– Configuration (Standby, Fault Queue enable for Remote 3 and 4; Conversion Rate)
– Channel Conversion Enable
– Filter Setting for Remote 1 and 2
– 1-Shot
5. Status Registers
– Main Status Register (Busy bit, Not Ready, Status Register 1 to 4 Flags)
– Status 1 (diode fault)
– Status 2 (TCRIT1)
– Status 3 (TCRIT2)
– Status 4 (TCRIT3)
6. Mask Registers
– TCRIT1 Mask
– TCRIT2 Mask
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Feature Description (continued)
– TCRIT3 Mask
7. Limit Registers
– Local Tcrit Limit
– Remote 1 Tcrit-1 Limit
– Remote 2 Tcrit-1 Limit
– Remote 3 Tcrit Limit
– Remote 4 Tcrit Limit
– Remote 1 Tcrit-2 and Tcrit-3 Limit
– Remote 2 Tcrit-2 and Tcrit-3 Limit
– Common Tcrit Hysteresis
8. Manufacturer ID Register
9. Revision ID Register
7.3.1 Conversion Sequence
The LM95214 takes approximately 190 ms to convert the Local Temperature, Remote Temperatures 1 through
4, and to update all of its registers. These conversions for each thermal diode are addressed in a round robin
sequence. Only during the conversion process the busy bit (D7) in Status register (02h) is high. The conversion
rate may be modified by the Conversion Rate bits found in the Configuration Register (03h). When the
conversion rate is modified a delay is inserted between each round of conversions, the actual time for each
round remains at 190 ms (typical all channels enabled). The time a round takes depends on the number of
channels that are on. Different conversion rates will cause the LM95214 to draw different amounts of average
supply current as shown in Figure 10. This curve assumes all the channels are on. If channels are turned off the
average current will drop because the round robin time will decrease and the shutdown time will increase during
each conversion interval.
3.0
VDD = +3.3V
AVERAGE I DD (mA)
2.5
TA = 25°C
2.0
1.5
1.0
0.5
0.0
100
1000
10000
CONVERSION TIME (ms)
Figure 10. Conversion Rate Effect on Power Supply Current
7.3.2 Power-On-Default States
The LM95214 always powers up to these known default states. The LM95214 remains in these states until after
the first conversion.
1. All Temperature readings set to 0°C until the end of the first conversion
2. Remote offset for all channels 0°C
3. Configuration: Active converting, Fault Queue enabled for Remote 3 and 4
4. Continuous conversion with all channels enabled, time = 1 s
5. Enhanced digital filter enabled for Remote 1 and 2
6. Status Registers depends on state of thermal diode inputs
7. Local and Remote Temperature Limits for TCRIT1, TCRIT2 and TCRIT3 outputs:
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Feature Description (continued)
Table 2. Temperature Channel limits
TEMPERATURE CHANNEL LIMIT
OUTPUT PIN
REMOTE 4
(°C)
REMOTE 3
(°C)
REMOTE 2
(°C)
REMOTE 1
(°C)
LOCAL
(°C)
TCRIT1
Masked,
85
Masked,
85
110
110
Masked,
85
TCRIT2
85
85
85
85
85
TCRIT3
85
85
Masked,
85
Masked,
85
Masked,
85
8. Manufacturers ID set to 01h
9. Revision ID set to 79h
7.3.3 SMBus Interface
The LM95214 operates as a slave on the SMBus, so the SMBCLK line is an input and the SMBDAT line is
bidirectional. The LM95214 never drives the SMBCLK line and it does not support clock stretching. According to
SMBus specifications, the LM95214 has a 7-bit slave address. Three SMBus device address can be selected by
connecting A0 (pin 6) to either Low, Mid-Supply, or High voltages. The LM95214 has the following SMBus slave
address:
Table 3. SMBus Slave Addresses
SMBus DEVICE ADDRESS A[6:0]
A0 PIN STATE
HEX
BINARY
Low
18h
001 1000
Mid-Supply
4Dh
100 1101
High
4Eh
100 1110
7.3.4 Temperature Conversion Sequence
Each of the 5 temperature channels of LM95214 can be turned OFF independent from each other through the
Channel Enable Register. Turning off unused channels will increase the conversion speed in the fastest
conversion speed mode. If the slower conversion speed settings are used, disabling unused channels will reduce
the average power consumption of LM95214.
7.3.4.1 Digital Filter
To suppress erroneous remote temperature readings due to noise as well as increase the resolution of the
temperature, the LM95214 incorporates a digital filter for Remote 1 and 2 Temperature Channels. When a filter is
enabled the filtered readings are used for the TCRIT comparisons. There are two possible digital filter settings
that are enabled through the Filter Setting Register at register address 0Fh. The filter for each channel can be
set according to the following table:
Table 4. Digital Filter Settings
R1F[1:0] OR R2F[1:0]
FILTER SETTING
0
0
No Filter
0
1
Filter (equivalent to Level 2 filter of the LM86/LM89)
1
0
Reserved
1
1
Enhanced Filter (Filter with transient noise clipping)
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Figure 11, Figure 12, and Figure 13 describe the filter output in response to a step input and an impulse input.
Figure 11. Seventeen and Fifty Degree Step Response
Figure 12. Impulse Response With Input Transients Less
Than 4°C
45
LM95214 with
Filter Off
43
TEMPERATURE (°C)
41
39
37
35
LM95214 with
Filter On
33
31
29
27
25
0
50
100
150
200
SAMPLE NUMBER
Figure 13. Impulse Response With Input Transients
Greater Than 4°C
Figure 14. Digital Filter Response in a Typical Intel
Processor on a 65 nm or 90 nm Process. The Filter Curves
Were Purposely Offset for Clarity.
Figure 14 shows the filter in use in a typical system. Note that the two curves have been purposely offset for
clarity. Inserting the filter does not induce an offset as shown.
7.3.5 Fault Queue
To suppress erroneous TCRIT1,TCRIT2 and TCRIT3 triggering the LM95214 incorporates a Fault Queue for the
unfiltered remote channels 3 and 4. The Fault Queue acts to ensure the remote temperature measurement of
these channels is genuinely beyond the corresponding Tcrit limit by not triggering until three consecutive out of
limit measurements have been made, see Figure 15 for an example. The Fault Queue defaults on upon powerup. The fault queue for channels 3 and 4 can be turned ON or OFF through bits 0 and 1 of the Configuration
Register. When the fault queue is enabled, the TCRIT1, TCRIT2 and TCRIT3 pins will be triggered if the
temperature is above the Tcrit limit for 3 consecutive conversions and the corresponding mask bit is 0 in the
TCRIT Mask registers. Similarly the temperature needs to be below the Tcrit limit minus the hysteresis value for
three consecutive conversions for the TCRIT1, TCRIT2 and TCRIT3 pins to deactivate.
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Remote 4 Temperature Readings
Remote 4
Tcrit Limit
Register
Value
n+11
n+9
n+10
n+8
n+7
n+6
n+5
n+4
n+3
n+2
n
n+1
Status 4
Register
R4T3 Bit
SAMPLE NUMBER
Figure 15. Fault Queue Response Diagram (With 0°C Hysteresis)
7.3.6 Temperature Data Format
Temperature data can only be read from the Local and Remote Temperature value registers. The data format for
all temperature values is left justified 16-bit word available in two 8-bit registers. Unused bits will always report 0.
All temperature data is clamped and will not roll over when a temperature exceeds full-scale value.
Remote temperature data for all channels can be represented by an 11-bit, two's complement word or unsigned
binary word with an LSb (Least Significant Bit) equal to 0.125°C.
Table 5. 11-Bit, 2's Complement (10-Bit Plus Sign)
TEMPERATURE
DIGITAL OUTPUT
BINARY
HEX
+125°C
0111 1101 0000 0000
7D00h
+25°C
0001 1001 0000 0000
1900h
+1°C
0000 0001 0000 0000
0100h
+0.125°C
0000 0000 0010 0000
0020h
0°C
0000 0000 0000 0000
0000h
−0.125°C
1111 1111 1110 0000
FFE0h
−1°C
1111 1111 0000 0000
FF00h
−25°C
1110 0111 0000 0000
E700h
−55°C
1100 1001 0000 0000
C900h
Table 6. 11-Bit Unsigned Binary
TEMPERATURE
DIGITAL OUTPUT
BINARY
HEX
+255.875°C
1111 1111 1110 0000
FFE0h
+255°C
1111 1111 0000 0000
FF00h
+201°C
1100 1001 0000 0000
C900h
+125°C
0111 1101 0000 0000
7D00h
+25°C
0001 1001 0000 0000
1900h
+1°C
0000 0001 0000 0000
0100h
+0.125°C
0000 0000 0010 0000
0020h
0°C
0000 0000 0000 0000
0000h
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When the digital filter is enabled on Remote 1 and 2 channels temperature data is represented by a 13-bit
unsigned binary or 12-bit plus sign (two's complement) word with an LSb equal to 0.03125°C.
Table 7. 13-Bit, 2's Complement (12-Bit Plus Sign)
TEMPERATURE
DIGITAL OUTPUT
BINARY
HEX
+125°C
0111 1101 0000 0000
7D00h
+25°C
0001 1001 0000 0000
1900h
+1°C
0000 0001 0000 0000
0100h
+0.03125°C
0000 0000 0000 1000
0008h
0°C
0000 0000 0000 0000
0000h
−0.03125°C
1111 1111 1111 1000
FFF8h
FF00h
−1°C
1111 1111 0000 0000
−25°C
1110 0111 0000 0000
E700h
−55°C
1100 1001 0000 0000
C900h
Table 8. 13-Bit, Unsigned Binary
TEMPERATURE
16
DIGITAL OUTPUT
BINARY
HEX
+255.875°C
1111 1111 1110 0000
FFE0h
+255°C
1111 1111 0000 0000
FF00h
+201°C
1100 1001 0000 0000
C900h
+125°C
0111 1101 0000 0000
7D00h
+25°C
0001 1001 0000 0000
1900h
+1°C
0000 0001 0000 0000
0100h
+0.03125°C
0000 0000 0000 1000
0008h
0°C
0000 0000 0000 0000
0000h
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Local Temperature data is only represented by an 11-bit, two's complement, word with an LSb equal to 0.125°C.
Table 9. 11-Bit, 2's Complement (10-Bit Plus Sign)
DIGITAL OUTPUT
TEMPERATURE
BINARY
HEX
+125°C
0111 1101 0000 0000
7D00h
+25°C
0001 1001 0000 0000
1900h
+1°C
0000 0001 0000 0000
0100h
+0.125°C
0000 0000 0010 0000
0020h
0°C
0000 0000 0000 0000
0000h
−0.125°C
1111 1111 1110 0000
FFE0h
−1°C
1111 1111 0000 0000
FF00h
−25°C
1110 0111 0000 0000
E700h
−55°C
1100 1001 0000 0000
C900h
7.3.7 SMBDAT Open-Drain Output
The SMBDAT output is an open-drain output and does not have internal pullups. A high level will not be
observed on this pin until pullup current is provided by some external source, typically a pullup resistor. Choice of
resistor value depends on many system factors but, in general, the pullup resistor must be as large as possible
without effecting the SMBus desired data rate. This will minimize any internal temperature reading errors due to
internal heating of the LM95214. The maximum resistance of the pullup to provide a 2.1-V high level, based on
LM95214 specification for High Level Output Current with the supply voltage at 3 V, is 82 kΩ (5%) or 88.7 kΩ
(1%).
7.3.8 TCRIT1, TCRIT2, and TCRIT3 Outputs
The LM95214's TCRIT pins are active-low open-drain outputs and do not include internal pullup resistors. A high
level will not be observed on these pins until pullup current is provided by some external source, typically a
pullup resistor. Choice of resistor value depends on many system factors but, in general, the pullup resistor must
be as large as possible without effecting the performance of the device receiving the signal. This will minimize
any internal temperature reading errors due to internal heating of the LM95214. The maximum resistance of the
pullup to provide a 2.1-V high level, based on LM95214 specification for High Level Output Current with the
supply voltage at 3 V, is 82 kΩ (5%) or 88.7 kΩ (1%). The three TCRIT pins can each sink 6 mA of current and
still ensured a Logic Low output voltage of 0.4 V. If all three pins are set at maximum current this will cause a
power dissipation of 7.2 mW. This power dissipation combined with a thermal resistance of 77.8°C/W will cause
the LM95214's junction temperature to rise approximately 0.6°C and thus cause the Local temperature reading to
shift. This can only be cancelled out if the environment that the LM95214 is enclosed in has stable and controlled
air flow over the LM95214, as airflow can cause the thermal resistance to change dramatically.
7.3.9 TCRIT Limits and TCRIT Outputs
Figure 16 describes a simplified diagram of the temperature comparison and status register logic. Figure 17,
Figure 18, and Figure 19 describe simplified logic diagrams of the circuitry associated with the status registers,
mask registers, and the TCRIT output pins.
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Remote Temp 4
Status 2
(TCRIT1)
A
AtB
B
S
Remote 4 Tcrit Limit
Q
A
R2T1
A B
+
-
R4T1
R3T1
R
B
R1T1
LT1
A
Remote Temp 3
AtB
B
S
Remote 3 Tcrit Limit
Q
R
A
A B
+
-
Remote Temp 2
B
A
AtB
B
S
Remote 2 Tcrit-1 Limit
Q
R
A
R4T2
A B
+
-
Status 3
(TCRIT2)
B
R3T2
R2T2
Remote Temp 1
R1T2
A
LT2
AtB
B
S
Remote 1 Tcrit-1 Limit
Q
R
A
A B
+
-
B
A
AtB
B
Remote 2 Tcrit-2 & Tcrit-3
Limit
S
Q
R
A
A B
+
-
Status 4
(TCRIT3)
B
R4T3
R3T3
A
R2T3
AtB
B
Remote 1 Tcrit2 & Tcrit-3
Limit
S
Q
R1T3
LT3
R
A
A B
+
-
B
A
Local Temp
AtB
B
S
Local Tcrit Limit
Q
R
A
A B
+
-
B
Common Tcrit Hysteresis
Figure 16. Temperature Comparison Logic and Status Register Simplified Diagram
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Status 1
(Diode Fault)
Status 1
(Diode Fault)
R4DO
R4DO
R4DS
R4DS
R3DO
R3DO
R3DS
R3DS
R2DO
R2DO
R2DS
R2DS
R1DO
R1DO
R1DS
R1DS
Status 2
(TCRIT1)
Status 3
(TCRIT2)
R4T1
R4T2
R3T1
R3T2
R2T1
TCRIT1
R2T2
R1T1
R1T2
LT1
LT2
TCRIT1
Mask
TCRIT2
Mask
R4TM
R4TM
R3TM
R3TM
R2T1M
R2T2M
R1T1M
R1T2M
LTM
LTM
Figure 17. TCRIT1 Mask Register, Status Register 1 and 2,
and TCRIT1 Output Logic Diagram
TCRIT2
Figure 18. TCRIT2 Mask Register, Status Register 1 and 3,
and TCRIT2 Output Logic Diagram
Status 1 (Diode
Fault)
R4DO
R4DS
R3DO
R3DS
R2DO
R2DS
R1DO
R1DS
Status 4
(TCRIT3)
R4T3
R3T3
R2T3
TCRIT3
R1T3
LT3
TCRIT3
Mask
R4TM
R3TM
R2T2M
R1T2M
LTM
Figure 19. TCRIT3 Mask Register, Status Register 1 and 4, and TCRIT3 Output Logic Diagram
If enabled, local temperature is compared to the user programmable Local Tcrit Limit Register (Default Value =
85°C). The result of this comparison is stored in Status Register 2, Status Register 3 and Status Register 4 (see
Figure 16). The comparison result can trigger TCRIT1 pin, TCRIT2 pin or TCRIT3 pin depending on the settings
in the TCRIT1 Mask, TCRIT2 Mask and TCRIT3 Mask Registers (see Figure 17, Figure 18, and Figure 19). The
comparison result can also be read back from the Status Register 2, Status Register 3 and Status Register 4.
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If enabled, remote temperature 1 is compared to the user programmable Remote 1 Tcrit-1 Limit Register (Default
Value 110°C) and Remote 1 Tcrit-2 Limit Register (Default Value = 85°C). The result of this comparison is stored
in Status Register 2, Status Register 3 and Status Register 4 (see Figure 16). The comparison result can trigger
TCRIT1 pin, TCRIT2 pin or TCRIT3 pin depending on the settings in the TCRIT1 Mask, TCRIT2 Mask and
TCRIT3 Mask Registers (see Figure 17, Figure 18, and Figure 19). The comparison result can also be read back
from the Status Register 2, Status Register 3 and Status Register 4. The remote temperature 2 operates in a
similar manner to remote temperature 1 using its associated user programmable limit registers: Remote 2 Tcrit-1
Limit Register (Default Value 110°C) and Remote 2 Tcrit-2 Limit Register (Default Value = 85°C). When enabled,
the remote temperature 3 is compared to the user programmable Remote 3 Tcrit Limit Register (Default Value
85°C). The comparison result can trigger TCRIT1 pin, TCRIT2 pin or TCRIT3 pin depending on the settings in
the TCRIT1 Mask, TCRIT2 Mask and TCRIT3 Mask Registers. The comparison result can also be read back
from the Status Register 2, Status Register 3 and Status Register 4. The remote temperature 4 operates in a
similar manner to remote temperature 3 using its associated user programmable limit register: Remote 4 Tcrit
Limit Register (Default Value 85°C).
Table 10. Limit Assignments for Each TCRIT Output Pin:
TCRIT1
TCRIT2
TCRIT3
Remote 4
Remote 4
Tcrit Limit
Remote 4
Tcrit Limit
Remote 4
Tcrit Limit
Remote 3
Remote 3
Tcrit Limit
Remote 3
Tcrit Limit
Remote 3
Tcrit Limit
Remote 2
Remote 2
Tcrit-1 Limit
Remote 2
Tcrit-2 Limit
Remote 2
Tcrit-2 Limit
Remote 1
Remote 1
Tcrit-1 Limit
Remote 1
Tcrit-2 Limit
Remote 1
Tcrit-2 Limit
Local
Local
Tcrit Limit
Local
Tcrit Limit
Local
Tcrit Limit
Local Tcrit Limit
Local Tcrit Limit Common Hysteresis
Local
Temperature
Common
Hysteresis
T_CRITn
Output Pin
Status bit LTn
Figure 20. TCRIT Response Diagram (Masking Options Not Included)
The TCRIT response diagram of Figure 20 shows the local temperature interaction with the Tcrit limit and
hysteresis value. As can be seen in the diagram when the local temperature exceeds the Tcrit limit register value
the LTn Status bit is set and the T_CRITn output(s) is/are activated. The Status bit(s) and outputs are not
deactivated until the temperature goes below the value calculated by subtracting the Common Hysteresis value
programmed from the limit. This diagram mainly shows an example function of the hysteresis and is not meant to
show complete function of the possible settings and options of all the TCRIT outputs and limit values.
7.4 Device Functional Modes
7.4.1 Diode Fault Detection
The LM95214 is equipped with operational circuitry designed to detect fault conditions concerning the remote
diodes. In the event that the D+ pin is detected as shorted to GND, D−, VDD or D+ is floating, the Remote
Temperature reading is –128.000°C if signed format is selected and 0°C if unsigned format is selected. In
addition, the appropriate status register bits RD1M or RD2M (D1 or D0) are set.
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Device Functional Modes (continued)
7.4.2 Communicating With the LM95214
The data registers in the LM95214 are selected by the Command Register. At power-up the Command Register
is set to 00, the location for the Read Local Temperature Register. The Command Register latches the last
location it was set to. Each data register in the LM95214 falls into one of three types of user accessibility:
1. Read only
2. Write only
3. Write/Read same address
A Write to the LM95214 will always include the address byte and the command byte. A write to any register
requires one data byte.
Reading the LM95214 can take place either of two ways:
1. If the location latched in the Command Register is correct (most of the time it is expected that the Command
Register will point to one of the Read Temperature Registers because that will be the data most frequently
read from the LM95214), then the read can simply consist of an address byte, followed by retrieving the data
byte.
2. If the Command Register needs to be set, then an address byte, command byte, repeat start, and another
address byte will accomplish a read.
The data byte has the most significant bit first. At the end of a read, the LM95214 can accept either acknowledge
or No Acknowledge from the Master (No Acknowledge is typically used as a signal for the slave that the Master
has read its last byte). It takes the LM95214 190 ms (typical, all channels enabled) to measure the temperature
of the remote diodes and internal diode. When retrieving all 11 bits from a previous remote diode temperature
measurement, the master must insure that all 11 bits are from the same temperature conversion. This may be
achieved by reading the MSB register first. The LSB will be locked after the MSB is read. The LSB will be
unlocked after being read. If the user reads MSBs consecutively, each time the MSB is read, the LSB associated
with that temperature will be locked in and override the previous LSB value locked-in.
1
9
1
9
SMBCLK
SMBDAT
A6
A5
A4
A3
A2
A1
D7
Ack
by
LM95214
D6
A0 R/W
Start by
Master
D5
Frame 1
Serial Bus Address Byte
D4
D3
D2
SMBDAT
(Continued)
D0
Ack
by
LM95214
Frame 2
Command Byte
1
SMBCLK
(Continued)
D1
9
D7
D6
D5
D4
D3
D2
D1
D0
Ack by Stop
LM95214 by
Master
Frame 3
Data Byte
Figure 21. Serial Bus Write to the Internal Command Register Followed by a the Data Byte
1
9
1
9
SMBCLK
SMBDAT
A6
A5
A4
A3
A2
A1
D7
Ack
by
LM95214
A0 R/W
Start by
Master
Frame 1
Serial Bus Address Byte
D6
D5
D4
D3
D2
Frame 2
Command Byte
D1
D0
Ack by Stop
LM95214 by
Master
Figure 22. Serial Bus Write to the Internal Command Register
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Device Functional Modes (continued)
1
9
1
9
SMBCLK
SMBDAT
A6
A4
A5
A2
A3
D7
Ack
by
LM95214
A1
D6
A0 R/W
Start by
Master
Frame 1
Serial Bus Address Byte
D5
D4
D3
D2
D1
D0
NoAck Stop
by
by
Master Master
Frame 2
Data Byte from the LM95214
Figure 23. Serial Bus Read From a Register With the Internal Command Register Preset to Desired Value
1
9
1
9
SMBCLK
SMBDAT
A6
A5
A4
A3
A2
A1
D7
Ack
by
LM95214
D6
A0 R/W
Start by
Master
D5
Frame 1
Serial Bus Address Byte
SMBCLK
(Continued)
SMBDAT
(Continued)
9
A5
A4
A3
A2
A1
D3
D2
D1
D0
Ack Repeat
by
Start by
LM95214 Master
Frame 2
Command Byte
1
A6
D4
D7
Ack
by
LM95214
A0 R/W
Frame 3
Serial Bus Address Byte
1
9
D6
D5
D4
D3
D2
D1
D0
Frame 4
Data Byte from the LM95214
No Ack Stop
by
by
Master Master
Figure 24. Serial Bus Write Followed by a Repeat Start and Immediate Read
7.4.3 Serial Interface Reset
In the event that the SMBus Master is RESET while the LM95214 is transmitting on the SMBDAT line, the
LM95214 must be returned to a known state in the communication protocol. This may be done in one of two
ways:
1. When SMBDAT is LOW, the LM95214 SMBus state machine resets to the SMBus idle state if either
SMBDAT or SMBCLK are held low for more than 35ms (tTIMEOUT). Note that according to SMBus
specification 2.0 all devices are to timeout when either the SMBCLK or SMBDAT lines are held low for 25 to
35 ms. Therefore, to insure a timeout of all devices on the bus the SMBCLK or SMBDAT lines must be held
low for at least 35 ms.
2. When SMBDAT is HIGH, have the master initiate an SMBus start. The LM95214 will respond properly to an
SMBus start condition at any point during the communication. After the start the LM95214 will expect an
SMBus Address byte.
7.4.4 One-Shot Conversion
The One-Shot register is used to initiate a round of conversions and comparisons when the device is in standby
mode, after which the device returns to standby. This is not a data register and it is the write operation that
causes the one-shot conversion. The data written to this address is irrelevant and is not stored. A zero will
always be read from this register. All the channels that are enabled in the Channel Enable Register will be
converted once and the TCRIT1, TCRIT2, and TCRIT3 pins will reflect the comparison results based on this
round of conversion results of the channels that are not masked.
22
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7.5 Register Maps
7.5.1 LM95214 Registers
Command register selects which registers will be read from or written to. Data for this register must be
transmitted during the Command Byte of the SMBus write communication.
P7
P6
P5
P4
P3
P2
P1
P0
Command Byte
P0-P7: Command
Table 11. Register Summary
Command
Byte
(Hex)
Read/
Write
D7
Local Temp MSB
0x10
RO
SIGN
Local Temp LSB
0x20
RO
1/2
Remote Temp 1 MSB – Signed
0x11
RO
SIGN
0x21
RO
1/2
Register Name
Remote Temp 1 LSB – Signed,
Digital Filter Off
Remote Temp 1 LSB – Signed,
Digital Filter On
Remote Temp 2 MSB – Signed
Remote Temp 2 LSB – Signed,
Digital Filter Off
Remote Temp 2 LSB – Signed,
Digital Filter On
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
64
32
16
8
4
2
1
–
1/4
1/8
0
0
0
0
0
–
64
32
16
8
4
2
1
–
0
0
1/4
1/8
0
0
0
–
1/16
1/32
16
8
4
2
1
–
0
0
0
0
0
–
1/16
1/32
D6
0x12
RO
SIGN
64
32
0x22
RO
1/2
1/4
1/8
Remote Temp 3 MSB – Signed
0x13
RO
SIGN
64
32
16
8
4
2
1
–
Remote Temp 3 LSB – Signed
0x23
RO
1/2
1/4
1/8
0
0
0
0
0
–
Remote Temp 4 MSB – Signed
0x14
RO
SIGN
64
32
16
8
4
2
0
–
Remote Temp 4 LSB – Signed
0x24
RO
1/2
1/4
1/8
0
0
0
0
0
–
Remote Temp 1 MSB – Unsigned
0x19
RO
128
64
32
16
8
4
2
1
–
0
0
0x29
RO
1/2
1/4
1/8
0
0
0
–
1/16
1/32
16
8
4
2
1
–
0
0
0
0
0
–
1/16
1/32
Remote Temp 1 LSB – Unsigned,
Digital Filter Off
Remote Temp 1 LSB – Unsigned,
Digital Filter On
Remote Temp 2 MSB – Unsigned
Remote Temp 2 LSB – Unsigned,
Digital Filter Off
Remote Temp 2 LSB – Unsigned,
Digital Filter On
0x1A
RO
128
64
32
0x2A
RO
1/2
1/4
1/8
Remote Temp 3 MSB – Unsigned
0x1B
RO
128
64
32
16
8
4
2
1
–
Remote Temp 3 LSB – Unsigned
0x2B
RO
1/2
1/4
1/8
0
0
0
0
0
–
Remote Temp 4 MSB – Unsigned
0x1C
RO
128
64
32
16
8
4
2
1
–
Remote Temp 4 LSB – Unsigned
0x2C
RO
1/2
1/4
1/8
0
0
0
0
0
–
Remote 1 Offset
0x31
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Remote 2 Offset
0x32
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Remote 3 Offset
0x33
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Remote 4 Offset
0x34
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Configuration
0x03
R/W
–
STBY
–
–
–
–
R4QE
R3QE
0x03
Conversion Rate
0x04
R/W
–
–
–
–
–
–
CR1
CR0
0x02
Channel Conversion Enable
0x05
R/W
–
–
–
R4CE
R3CE
R2CE
R1CE
LCE
0x1F
Filter Setting
0x06
R/W
–
–
–
–
R2F1
R2F0
R1F1
R1F0
0x0F
1-shot
0x0F
WO
–
–
–
–
–
–
–
–
–
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Table 11. Register Summary (continued)
Command
Byte
(Hex)
Read/
Write
D0
POR
Default
(Hex)
Common Status Register
0x02
RO
BUSY
NR
–
–
SR4F
SR3F
Status 1 (Diode Fault)
0x07
RO
R4DO
R4DS
R3DO
R3DS
R2DO
R2DS
SR2F
SR1F
0x00
R1DO
R1DS
–
Status 2 (TCRIT1)
0x08
RO
–
–
–
R4T1
R3T1
R2T1
Status 3 (TCRIT2)
0x09
RO
–
–
–
R4T2
R3T2
R2T2
R1T1
LT1
–
R1T2
LT2
Status 4 (TCRIT3)
0x0A
RO
–
–
–
R4T3
R3T3
–
R2T3
R1T3
LT3
TCRIT1 Mask
0x0C
R/W
–
–
–
R4TM
–
R3TM
R2T1M
R1T1M
LTM
0x19
TCRIT2 Mask
0x0D
R/W
–
–
–
TCRIT3 Mask
0x0E
R/W
–
–
–
R4TM
R3TM
R2T2M
R1T2M
LTM
0x00
R4TM
R3TM
R2T2M
R1T2M
LTM
Local Tcrit Limit
0x40
R/W
0
64
0x07
32
16
8
4
2
1
0x55
Remote 1 Tcrit-1 Limit
0x41
R/W
128
Remote 2 Tcrit-1 Limit
0x42
R/W
128
64
32
16
8
4
2
1
0x6E
64
32
16
8
4
2
1
Remote 3 Tcrit Limit
0x43
R/W
0x6E
128
64
32
16
8
4
2
1
0x55
Remote 4 Tcrit Limit
0x44
Remote 1 Tcrit-2 and Tcrit-3 Limit
0x49
R/W
128
64
32
16
8
4
2
1
0x55
R/W
128
64
32
16
8
4
2
1
Remote 2 Tcrit-2 and Tcrit-3 Limit
0x55
0x4A
R/W
128
64
32
16
8
4
2
1
0x55
Common Tcrit Hysteresis
0x5A
R/W
0
0
0
16
8
4
2
1
0x0A
Manufacturer ID
0xFE
RO
0
0
0
0
0
0
0
1
0x01
Revision ID
0xFF
RO
0
1
1
1
1
0
0
1
0x79
Register Name
D7
D6
D5
D4
D3
D2
D1
7.5.1.1 Value Registers
For data synchronization purposes, the MSB register must be read first if the user wants to read both MSB and
LSB registers. The LSB will be locked after the MSB is read. The LSB will be unlocked after being read. If the
user reads MSBs consecutively, each time the MSB is read, the LSB associated with that temperature will be
locked in and override the previous LSB value locked-in
7.5.1.1.1 Local Value Registers
Command
Read/
Byte
Write
(Hex)
Register Name
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
Local Temp MSB
0x10
RO
SIGN
64
32
16
8
4
2
1
–
Local Temp LSB
0x20
RO
1/2
1/4
1/8
0
0
0
0
0
–
Bit(s)
Bit Name
Read/Write
Description
7
SIGN
RO
Sign bit
6
64
RO
bit weight 64°C
5
32
RO
bit weight 32°C
4
16
RO
bit weight 16°C
3
8
RO
bit weight 8°C
2
4
RO
bit weight 4°C
1
2
RO
bit weight 2°C
0
1
RO
bit weight 1°C
Bit(s)
Bit Name
Read/Write
Description
7
1/2
RO
bit weight 1/2°C (0.5°C)
6
1/4
RO
bit weight 1/4°C (0.25°C)
5
1/8
RO
bit weight 1/8°C (0.125°C)
4-0
0
RO
Reserved – will report 0 when read.
24
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The Local temperature MSB value register
range is +127°C to −128°C. The value
programmed in this register is used to
determine a local temperature error event.
The Local Limit register range is 0°C to
127°C. The value programmed in this
register is used to determine a local
temperature error event.
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7.5.1.1.2 Remote Temperature Value Registers With Signed Format
Command
Read/
Byte
Write
(Hex)
Register Name
Remote Temp 1 MSB – Signed
Remote Temp 1 LSB – Signed, Digital
Filter Off
Remote Temp 1 LSB – Signed, Digital
Filter On
Remote Temp 2 MSB – Signed
Remote Temp 2 LSB – Signed, Digital
Filter Off
Remote Temp 2 LSB – Signed, Digital
Filter On
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
32
16
8
4
2
1
–
0
0
0
0
0
0
–
1/16
1/32
32
16
8
4
2
1
–
0
0
0
0
0
0
–
1/16
1/32
0x11
RO
SIGN
64
0x21
RO
1/2
1/8
0x12
RO
SIGN
64
0x22
RO
1/2
1/8
Remote Temp 3 MSB – Signed
0x13
RO
SIGN
64
32
16
8
4
2
1
–
Remote Temp 3 LSB – Signed
0x23
RO
1/2
1/8
0
0
0
0
0
0
–
Remote Temp 4 MSB – Signed
0x14
RO
SIGN
64
32
16
8
4
2
0
–
Remote Temp 4 LSB – Signed
0x24
RO
1/2
1/8
0
0
0
0
0
0
–
The Local temperature MSB value register range is +127°C to −128°C. The value programmed in this register is
used to determine a local temperature error event.
Bit(s)
Bit Name
Read/Write
Description
7
SIGN
RO
Sign bit
6
64
RO
bit weight 64°C
5
32
RO
bit weight 32°C
4
16
RO
bit weight 16°C
3
8
RO
bit weight 8°C
2
4
RO
bit weight 4°C
1
2
RO
bit weight 2°C
0
1
RO
bit weight 1°C
Bit(s)
Bit Name
Read/Write
Description
7
1/2
RO
bit weight 1/2°C (0.5°C)
6
1/4
RO
bit weight 1/4°C (0.25°C)
5
1/8
RO
bit weight 1/8°C (0.125°C)
4
0 or 1/16
RO
When the digital filter is disabled this bit will always read 0.
When the digital filter is enabled this bit will report 1/16°C (0.0625°C) bit state.
3
0 or 1/32
RO
When the digital filter is disabled this bit will always read 0.
When the digital filter is enabled this bit will report 1/32°C (0.03125°C) bit state.
2-0
0
RO
Reserved – will report 0 when read.
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7.5.1.1.3 Remote Temperature Value Registers With Unsigned Format
Command
Read/
Byte
Write
(Hex)
Register Name
Remote Temp 1 MSB – Unsigned
Remote Temp 1 LSB – Unsigned,
Digital Filter Off
Remote Temp 1 LSB – Unsigned,
Digital Filter On
Remote Temp 2 MSB – Unsigned
Remote Temp 2 LSB – Unsigned,
Digital Filter Off
Remote Temp 2 LSB – Unsigned,
Digital Filter On
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
32
16
8
4
2
1
–
0
0
0
0
0
0
–
1/16
1/32
32
16
8
4
2
1
–
0
0
0
0
0
0
–
1/16
1/32
0x19
RO
128
64
0x29
RO
1/2
1/8
0x1A
RO
128
64
0x2A
RO
1/2
1/8
Remote Temp 3 MSB – Unsigned
0x1B
RO
128
64
32
16
8
4
2
1
–
Remote Temp 3 LSB – Unsigned
0x2B
RO
1/2
1/8
0
0
0
0
0
0
–
Remote Temp 4 MSB – Unsigned
0x1C
RO
128
64
32
16
8
4
2
1
–
Remote Temp 4 LSB – Unsigned
0x2C
RO
1/2
1/8
0
0
0
0
0
0
–
Bit(s)
Bit Name
Read/Write
Description
7
SIGN
RO
bit weight 128°C
6
64
RO
bit weight 64°C
5
32
RO
bit weight 32°C
4
16
RO
bit weight 16°C
3
8
RO
bit weight 8°C
2
4
RO
bit weight 4°C
1
2
RO
bit weight 2°C
0
1
RO
bit weight 1°C
Bit(s)
Bit Name
Read/Write
Description
7
1/2
RO
bit weight 1/2°C (0.5°C)
6
1/4
RO
bit weight 1/4°C (0.25°C)
5
1/8
RO
bit weight 1/8°C (0.125°C)
4
0 or 1/16
RO
When the digital filter is disabled this bit will always read 0.
When the digital filter is enabled this bit will report 1/16°C (0.0625°C) bit state.
3
0 or 1/32
RO
When the digital filter is disabled this bit will always read 0.
When the digital filter is enabled this bit will report 1/32°C (0.03125°C) bit state.
2-0
0
RO
Reserved – will report 0 when read.
26
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7.5.1.2 Diode Configuration Register
7.5.1.2.1 Remote 1-4 Offset
Command
Read/
Byte
Write
(Hex)
Register Name
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
Remote 1 Offset
0x31
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Remote 2 Offset
0x32
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Remote 3 Offset
0x33
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Remote 4 Offset
0x34
R/W
SIGN
32
16
8
4
2
1
1/2
0x00
Bit(s)
Bit Name
Read/Write
Description
7
SIGN
R/W
Sign bit
6
32
R/W
bit weight 32°C
5
16
R/W
bit weight 16°C
4
8
R/W
bit weight 8°C
3
4
R/W
bit weight 4°C
2
2
R/W
bit weight 2°C
1
1
R/W
bit weight 1°C
0
1/2
R/W
bit weight 1/2°C (0.5°C)
All registers have 2’s complement format.
The offset range for each remote is
+63.5°C/−64°C. The value programmed in
this register is directly added to the actual
reading of the ADC and the modified number
is reported in the remote value registers.
7.5.1.3 Configuration Registers
7.5.1.3.1 Main Configuration Register
Command
Read/
Byte
Write
(Hex)
Register Name
Configuration
0×03
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
STBY
–
–
–
–
R4QE
R3QE
0×03
Bit(s)
Bit Name
Read/Write
Description
7
–
RO
Reserved will report 0 when read.
6
STBY
R/W
Software Standby
1 – standby (when in this mode one conversion sequence can be initiated by writing to the
one-shot register)
0 – active/converting
5–2
–
RO
Reserved – will report 0 when read.
1
R4QE
R/W
Fault queue enable for Remote 4
1– Fault queue enabled
0– Fault queue disabled
0
R3QE
R/W
Fault queue enable for Remote 3
1– Fault queue enabled
0– Fault queue disabled
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7.5.1.3.2 Conversion Rate Register
Command
Read/
Byte
Write
(Hex)
Register Name
Conversion Rate
0×04
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
–
–
–
CR1
CR0
0×02
Bit(s)
Bit Name
Read/Write
Description
7-2
–
RO
Reserved – will report 0 when read.
1-0
CR[1:0]
R/W
Conversion rate control bits modify the time interval for conversion of the channels enabled.
The channels enabled are converted sequentially then standby mode enabled for the
remainder of the time interval.
CR[1:0]
Conversion Rate
00
continuous (30 ms to 143 ms)
01
0.364 s
10
1s
11
2.5 s
7.5.1.3.3 Channel Conversion Enable
When a conversion is disabled for a particular channel it is skipped. The continuous conversion rate is effected
all other conversion rates are not effected as extra standby time is inserted to compensate. See Conversion Rate
Register description.
Command
Read/
Byte
Write
(Hex)
Register Name
Channel Conversion Enable
0×05
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
R4CE
R3CE
R2CE
R1CE
LCE
0×1F
Bit(s)
Bit Name
Read/Write
Description
7–5
–
RO
Reserved – will report 0 when read.
4
R4CE
R/W
Remote 4 Temperature Conversion Enable
1– Remote 4 temp conversion enabled
0– Remote 4 temp conversion disabled
3
R3CE
R/W
Remote 3 Temperature Conversion Enable
1– Remote 3 temp conversion enabled
0– Remote 3 temp conversion disabled
2
R2CE
R/W
Remote 2 Temperature Conversion Enable
1– Remote 2 temp conversion enabled
0– Remote 2 temp conversion disabled
1
R1CE
R/W
Remote 1 Temperature Conversion Enable
1– Remote 1 temp conversion enabled
0– Remote 1 temp conversion disabled
0
LCE
R/W
Local Temperature Conversion Enable
1– Local temp conversion enabled
0– Local temp conversion disabled
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7.5.1.3.4 Filter Setting
Command
Read/
Byte
Write
(Hex)
Register Name
Filter Setting
0x06
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
–
R2F1
R2F0
R1F1
R1F0
0x0F
Bit(s)
Bit Name
Read/Write
Description
7–4
–
RO
Reserved – will report 0 when read.
3–2
R2F[1:0]
R/W
Remote Channel 2 Filter Enable Bits
R2F[1:0]
1–0
R1F[1:0]
R/W
Digital Filter State
00
disable all digital filtering
01
enable basic filter
10
reserved (do not use)
11
enable enhanced filter
Remote Channel 1 Filter Enable
R1F[1:0]
Filter State
00
disable all digital filtering
01
enable basic filter
10
reserved (do not use)
11
enable enhanced filter
7.5.1.3.5 1-Shot
Register Name
Command
Read/
Byte
Write
(Hex)
1-Shot
0×0F
WO
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
–
–
–
–
–
–
Bit(s)
Bit Name
Read/Write
Description
7–0
-
WO
Writing to this register activates one conversion for all the enabled channels if the
chip is in standby mode (that is,. standby bit = 1). The actual data written does
not matter and is not stored.
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7.5.1.4 Status Registers
7.5.1.4.1 Common Status Register
Command
Read/
Byte
Write
(Hex)
Register Name
Common Status Register
0×02
RO
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
BUSY
NR
–
–
SR4F
SR3F
SR2F
SR1F
0×00
Bit(s)
Bit Name
Read/Write
Description
7
BUSY
RO
Busy bit (device converting)
6
NR
RO
Not Ready bit (30 ms), indicates power up initialization sequence is in progress
5–4
–
RO
Reserved – will report 0 when read.
3
SR4F
RO
Status Register 4 Flag:
1 – indicates that Status Register 4 has at least one bit set
0 – indicates that all of Status Register 4 bits are cleared
2
SR3F
RO
Status Register 3 Flag:
1 – indicates that Status Register 3 has at least one bit set
0 – indicates that all of Status Register 3 bits are cleared
1
SR2F
RO
Status Register 2 Flag:
1 – indicates that Status Register 2 has at least one bit set
0 – indicates that all of Status Register 2 bits are cleared
0
SR1F
RO
Status Register 1 Flag:
1 – indicates that Status Register 1 has at least one bit set
0 – indicates that all of Status Register 1 bits are cleared
7.5.1.4.2 Status 1 Register (Diode Fault)
Status fault bits for open or shorted diode (that is,. Short Fault: D+ shorted to Ground or D-; Open Fault: D+
shorted to VDD, or floating). During fault conditions the temperature reading is 0 °C if unsigned value registers are
read or –128.000 °C if signed value registers are read.
Command
Read/
Byte
Write
(Hex)
Register Name
Status 1 (Diode Fault)
0×07
RO
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
R4DO
R4DS
R3DO
R3DS
R2DO
R2DS
R1DO
R1DS
–
Bit(s)
Bit Name
Read/Write
Description
7
R4DO
RO
Remote 4 diode open fault status:
1 – indicates that remote 4 diode has an "open" fault
0 – indicates that remote 4 diode does not have an "open" fault
6
R4DS
RO
Remote 4 diode short fault status:
1 – indicates that remote 4 diode has a "short" fault
0 – indicates that remote 4 diode does not have a "short" fault
5
R3DO
RO
Remote 3 diode open fault status:
1 – indicates that remote 3 diode has an "open" fault
0 – indicates that remote 3 diode does not have an "open" fault
4
R3DS
RO
Remote 3 diode short fault status:
1 – indicates that remote 3 diode has a "short" fault
0 – indicates that remote 3 diode does not have a "short" fault
3
R2DO
RO
Remote 2 diode open fault status:
1 – indicates that remote 2 diode has an "open" fault
0 – indicates that remote 2 diode does not have an "open" fault
2
R2DS
RO
Remote 2 diode short fault status:
1 – indicates that remote 2 diode has a "short" fault
0 – indicates that remote 2 diode does not have a "short" fault
1
R1DO
RO
Remote 1 diode open fault status:
1 – indicates that remote 1 diode has an "open" fault
0 – indicates that remote 1 diode does not have an "open" fault
30
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Bit(s)
Bit Name
Read/Write
Description
0
R1DS
RO
Remote 1 diode short fault status:
1 – indicates that remote 1 diode has a "short" fault
0 – indicates that remote 1 diode does not have a "short" fault
7.5.1.4.3 Status 2 (TCRIT1)
Status bits for TCRIT1. When one or more of these bits are set and if not masked the TCRIT1 output will
activate. TCRIT1 will deactivate when all these bits are cleared.
Command
Read/
Byte
Write
(Hex)
Register Name
Status 2 (TCRIT1)
0×08
RO
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
R4T1
R3T1
R2T1
R1T1
LT1
–
Bit(s)
Bit Name
Read/Write
Description
7–5
-
RO
Reserved – will report 0 when read.
4
R4T1
RO
Remote 4 Tcrit Status:
1 – indicates that remote 4 reading is greater than or equal to the value set in Remote 4 Tcrit
Limit register
0 – indicates that that remote 4 reading is less than the value set in Remote 4 Tcrit Limit register
minus the Common Hysteresis value
3
R3T1
RO
Remote 3 Tcrit Status:
1 – indicates that remote 3 reading is greater than or equal to the value set in Remote 3 Tcrit
Limit register
0 – indicates that that remote 3 reading is less than the value set in Remote 3 Tcrit Limit register
minus the Common Hysteresis value
2
R2T1
RO
Remote 2 Tcrit-1 Status:
1 – indicates that remote 2 reading is greater than or equal to the value set in Remote 2 Tcrit-1
Limit register
0 – indicates that that remote 2 reading is less than the value set in Remote 2 Tcrit-1 Limit
register minus the Common Hysteresis value
1
R1T1
RO
Remote 1 Tcrit-1 Status:
1 – indicates that remote 1 reading is greater than or equal to the value set in Remote 1 Tcrit-1
Limit register
0 – indicates that that remote 1 reading is less than the value set in Remote 1 Tcrit-1 Limit
register minus the Common Hysteresis value
0
LT1
RO
Local Tcrit Status:
1 – indicates that local reading is greater than or equal to the value set in Local Tcrit Limit
register
0 – indicates that local reading is less than the value set in Local Tcrit Limit register minus the
Common Hysteresis value
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7.5.1.4.4 Status 3 (TCRIT2)
Status bits for TCRIT2. When one or more of these bits are set and if not masked the TCRIT2 output will
activate. TCRIT2 will deactivate when all these bits are cleared.
Command
Read/
Byte
Write
(Hex)
Register Name
Status 3 (TCRIT2)
0×09
RO
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
R4T2
R3T2
R2T2
R1T2
LT2
–
Bit(s)
Bit Name
Read/Write
Description
7–5
-
RO
Reserved – will report 0 when read.
4
R4T2
RO
Remote 4 Tcrit Status:
1 – indicates that remote 4 reading is greater than or equal to the value set in Remote 4 Tcrit
Limit register
0 – indicates that that remote 4 reading is less than the value set in Remote 4 Tcrit Limit register
minus the Common Hysteresis value
3
R3T2
RO
Remote 3 Tcrit Status:
1 – indicates that remote 3 reading is greater than or equal to the value set in Remote 3 Tcrit
Limit register
0 – indicates that that remote 3 reading is less than the value set in Remote 3 Tcrit Limit register
minus the Common Hysteresis value
2
R2T2
RO
Remote 2 Tcrit-2 Status:
1 – indicates that remote 2 reading is greater than or equal to the value set in Remote 2 Tcrit-2
Limit register
0 – indicates that that remote 2 reading is less than the value set in Remote 2 Tcrit-2 Limit
register minus the Common Hysteresis value
1
R1T2
RO
Remote 1 Tcrit-2 Status:
1 – indicates that remote 1 reading is greater than or equal to the value set in Remote 1 Tcrit-2
Limit register
0 – indicates that that remote 1 reading is less than the value set in Remote 1 Tcrit-2 Limit
register minus the Common Hysteresis value
0
LT2
RO
Local Tcrit Status:
1 – indicates that local reading is greater than or equal to the value set in Local Tcrit Limit
register
0 – indicates that local reading is less than the value set in Local Tcrit Limit register minus the
Common Hysteresis value
32
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7.5.1.4.5 Status 4 (TCRIT3)
Status bits for TCRIT3. When one or more of these bits are set and if not masked the TCRIT3 output will
activate. TCRIT3 will deactivate when all these bits are cleared.
Command
Read/
Byte
Write
(Hex)
Register Name
Status 4 (TCRIT3)
0×0A
RO
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
R4T3
R3T3
R2T3
R1T3
LT3
–
Bit(s)
Bit Name
Read/Write
Description
7–5
-
RO
Reserved – will report 0 when read.
4
R4T3
RO
Remote 4 Tcrit Status:
1 – indicates that remote 4 reading is greater than or equal to the value set in Remote 4 Tcrit
Limit register
0 – indicates that that remote 4 reading is less than the value set in Remote 4 Tcrit Limit register
minus the Common Hysteresis value
3
R3T3
RO
Remote 3 Tcrit Status:
1 – indicates that remote 3 reading is greater than or equal to the value set in Remote 3 Tcrit
Limit register
0 – indicates that that remote 3 reading is less than the value set in Remote 3 Tcrit Limit register
minus the Common Hysteresis value
2
R2T3
RO
Remote 2 Tcrit-2 Status:
1 – indicates that remote 2 reading is greater than or equal to the value set in Remote 2 Tcrit-2
Limit register
0 – indicates that that remote 2 reading is less than the value set in Remote 2 Tcrit-2 Limit
register minus the Common Hysteresis value
1
R1T3
RO
Remote 1 Tcrit-2 Status:
1 – indicates that remote 1 reading is greater than or equal to the value set in Remote 1 Tcrit-2
Limit register
0 – indicates that that remote 1 reading is less than the value set in Remote 1 Tcrit-2 Limit
register minus the Common Hysteresis value
0
LT3
RO
Local Tcrit Status:
1 – indicates that local reading is greater than or equal to the value set in Local Tcrit Limit
register
0 – indicates that local reading is less than the value set in Local Tcrit Limit register minus the
Common Hysteresis value
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7.5.1.5 Mask Registers
7.5.1.5.1 TCRIT1 Mask Register
The mask bits in this register allow control over which error events propagate to the TCRIT1 pin.
Command
Read/
Byte
Write
(Hex)
Register Name
TCRIT1 Mask
0×0C
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
R4TM
R3TM
R2T1
M
R1T1
M
LTM
0×19
Bit(s)
Bit Name
Read/Write
Description
7-5
–
RO
Reserved – will report 0 when read.
4
R4TM
R/W
Remote 4 Tcrit Mask:
1 – prevents the remote 4 temperature error event from propagating to the TCRIT1 pin
0 – allows the remote 4 temperature error event to propagate to the TCRIT1 pin
3
R3TM
R/W
Remote 3 Tcrit Mask:
1 – prevents the remote 3 temperature error event from propagating to the TCRIT1 pin
0 – allows the remote 3 temperature error event to propagate to the TCRIT1 pin
2
R2T1M
R/W
Remote 2 Tcrit-1 Mask:
1 – prevents the remote 2 temperature error event from propagating to the TCRIT1 pin
0 – allows the remote 2 temperature error event to propagate to the TCRIT1 pin
1
R1T1M
R/W
Remote 1 Tcrit-1 Mask:
1 – prevents the remote 1 temperature error event from propagating to the TCRIT1 pin
0 – allows the remote 1 temperature error event to propagate to the TCRIT1 pin
0
LTM
R/W
Local Tcrit Mask:
1 – prevents the local temperature error event from propagating to the TCRIT1 pin
0 – allows the local temperature error event to propagate to the TCRIT1 pin
7.5.1.5.2 TCRIT2 Mask Registers
Command
Read/
Byte
Write
(Hex)
Register Name
TCRIT2 Mask
0×0D
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
R4TM
R3TM
R2T2
M
R1T2
M
LTM
0×00
Bit(s)
Bit Name
Read/Write
Description
7-5
–
RO
Reserved – will report 0 when read.
4
R4TM
R/W
Remote 4 Tcrit Mask:
1 – prevents the remote 4 temperature error event from propagating to the TCRIT2 pin
0 – allows the remote 4 temperature error event to propagate to the TCRIT2 pin
3
R3TM
R/W
Remote 3 Tcrit Mask:
1 – prevents the remote 3 temperature error event from propagating to the TCRIT2 pin
0 – allows the remote 3 temperature error event to propagate to the TCRIT2 pin
2
R2T2M
R/W
Remote 2 Tcrit-2 Mask:
1 – prevents the remote 2 temperature error event from propagating to the TCRIT2 pin
0 – allows the remote 2 temperature error event to propagate to the TCRIT2 pin
1
R1T2M
R/W
Remote 1 Tcrit-2 Mask:
1 – prevents the remote 1 temperature error event from propagating to the TCRIT2 pin
0 – allows the remote 1 temperature error event to propagate to the TCRIT2 pin
0
LTM
R/W
Local Tcrit Mask:
1 – prevents the local temperature error event from propagating to the TCRIT2 pin
0 – allows the local temperature error event to propagate to the TCRIT2 pin
34
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7.5.1.5.3 TCRIT3 Mask Register
The mask bits in this register allow control over which error events propagate to the TCRIT3 pin.
Command
Read/
Byte
Write
(Hex)
Register Name
TCRIT3 Mask
0×0E
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
–
–
–
R4TM
R3TM
R2T2
M
R1T2
M
LTM
0×07
Bit(s)
Bit Name
Read/Write
Description
7-5
–
RO
Reserved – will report 0 when read.
4
R4TM
R/W
Remote 4 Tcrit Mask:
1 – prevents the remote 4 temperature error event from propagating to the TCRIT3 pin
0 – allows the remote 4 temperature error event to propagate to the TCRIT3 pin
3
R3TM
R/W
Remote 3 Tcrit Mask:
1 – prevents the remote 3 temperature error event from propagating to the TCRIT3 pin
0 – allows the remote 3 temperature error event to propagate to the TCRIT3 pin
2
R2T2M
R/W
Remote 2 Tcrit-2 Mask:
1 – prevents the remote 2 temperature error event from propagating to the TCRIT3 pin
0 – allows the remote 2 temperature error event to propagate to the TCRIT3 pin
1
R1T2M
R/W
Remote 1 Tcrit-2 Mask:
1 – prevents the remote 1 temperature error event from propagating to the TCRIT3 pin
0 – allows the remote 1 temperature error event to propagate to the TCRIT3 pin
0
LTM
R/W
Local Tcrit Mask:
1 – prevents the local temperature error event from propagating to the TCRIT3 pin
0 – allows the local temperature error event to propagate to the TCRIT3 pin
7.5.1.6 Limit Registers
7.5.1.6.1 Local Limit Register
The Local Limit register range is 0°C to 127°C. The value programmed in this register is used to determine a
local temperature error event.
Command
Read/
Byte
Write
(Hex)
Register Name
Local Tcrit Limit
0×40
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
0
64
32
16
8
4
2
1
0×55
Bit(s)
Bit Name
Read/Write
Description
7
0
R0
Read only bit will always report 0.
6
64
R/W
bit weight 64°C
5
32
R/W
bit weight 32°C
4
16
R/W
bit weight 16°C
3
8
R/W
bit weight 8°C
2
4
R/W
bit weight 4°C
1
2
R/W
bit weight 2°C
0
1
R/W
bit weight 1°C
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7.5.1.6.2 Remote Limit Registers
The range for these registers is 0°C to 255°C.
Command
Read/
Byte
Write
(Hex)
Register Name
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
Remote 1 Tcrit-1 Limit (used by
TCRIT1 error events)
0x41
R/W
128
64
32
16
8
4
2
1
0x6E
Remote 2 Tcrit-1 Limit (used by
TCRIT1 error events)
0x42
R/W
128
64
32
16
8
4
2
1
0x6E
Remote 3 Tcrit Limit (used by TCRIT1,
TCRIT2 and TCRIT3 error events)
0x43
R/W
128
64
32
16
8
4
2
1
0x55
Remote 4 Tcrit Limit (used by TCRIT1,
TCRIT2 and TCRIT3 error events)
0x44
R/W
128
64
32
16
8
4
2
1
0x55
Remote 1 Tcrit-2 and Tcrit3 Limit (used
by TCRIT2 and TCRIT3 error events)
0x49
R/W
128
64
32
16
8
4
2
1
0x55
Remote 2 Tcrit-2 and Tcrit3 Limit (used
by TCRIT2 and TCRIT3 error events)
0x4A
R/W
128
64
32
16
8
4
2
1
0x55
Bit(s)
Bit Name
Read/Write
Description
7
128
R/W
bit weight 128°C
6
64
R/W
bit weight 64°C
5
32
R/W
bit weight 32°C
4
16
R/W
bit weight 16°C
3
8
R/W
bit weight 8°C
2
4
R/W
bit weight 4°C
1
2
R/W
bit weight 2°C
0
1
R/W
bit weight 1°C
Limit assignments for each TCRIT output pin:
36
OUTPUT PIN
REMOTE 4
REMOTE 3
REMOTE 2
REMOTE 1
LOCAL
TCRIT1
Remote 4 Tcrit Limit
Remote 3 Tcrit Limit
Remote 2 Tcrit-1
Limit
Remote 1 Tcrit-1
Limit
Local Tcrit Limit
TCRIT2
Remote 4 Tcrit Limit
Remote 3 Tcrit Limit
Remote 2 Tcrit-2
Limit
Remote 1 Tcrit-2
Limit
Local Tcrit Limit
TCRIT3
Remote 4 Tcrit Limit
Remote 3 Tcrit Limit
Remote 2 Tcrit-2
Limit
Remote 1 Tcrit-2
Limit
Local Tcrit Limit
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7.5.1.6.3 Common Tcrit Hysteresis Register
The hysteresis register range is 0°C to 32°C. The value programmed in this register is used to modify all the limit
values for decreasing temperature.
Command
Read/
Byte
Write
(Hex)
Register Name
Common Tcrit Hysteresis
0×5A
R/W
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
0
0
0
16
8
4
2
1
0×0A
Bit(s)
Bit Name
Read/Write
Description
7
0
RO
Read only bit will always report 0.
6
0
RO
Read only bit will always report 0.
5
0
RO
Read only bit will always report 0.
4
16
R/W
bit weight 16°C
3
8
R/W
bit weight 8°C
2
4
R/W
bit weight 4°C
1
2
R/W
bit weight 2°C
0
1
R/W
bit weight 1°C
7.5.1.7 Identification Registers
Register Name
Command
Read/
Byte
Write
(Hex)
D7
D6
D5
D4
D3
D2
D1
D0
POR
Default
(Hex)
Manufacturer ID
0×FE
RO
0
0
0
0
0
0
0
1
0×01
Revision ID
0×FF
RO
0
1
1
1
1
0
0
1
0×79
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LM95214 can be applied easily in the same way as other integrated-circuit temperature sensors, and its
remote diode sensing capability allows it to be used in new ways as well. It can be soldered to a printed-circuit
board, and because the path of best thermal conductivity is between the die and the pins, its temperature will
effectively be that of the printed-circuit board lands and traces soldered to the LM95214's pins. This presumes
that the ambient air temperature is almost the same as the surface temperature of the printed-circuit board; if the
air temperature is much higher or lower than the surface temperature, the actual temperature of the LM95214 die
will be at an intermediate temperature between the surface and air temperatures. Again, the primary thermal
conduction path is through the leads, so the circuit board temperature will contribute to the die temperature much
more strongly than will the air temperature.
8.2 Typical Application
To measure temperature external to the LM95214's die, incorporates remote diode sensing technology. This
diode can be located on the die of a target IC, allowing measurement of the IC's temperature, independent of the
LM95214's temperature. A discrete diode can also be used to sense the temperature of external objects or
ambient air. Remember that a discrete diode's temperature will be affected, and often dominated, by the
temperature of its leads. Most silicon diodes do not lend themselves well to this application. TI recommends that
an MMBT3904 transistor base emitter junction be used with the collector tied to the base.
The LM95214 can measure a diode-connected transistor such as the MMBT3904 or the thermal diode found in
an AMD processor. The LM95214 has been optimized to measure the MMBT3904 remote thermal diode the
offset register can be used to calibrate for other thermal diodes easily. The LM95214 does not include
TruTherm™ technology that allows sensing of sub-micron geometry process thermal diodes. For this application
the LM95234 would be better suited.
The LM95234 has been specifically optimized to measure the remote thermal diode integrated in a typical Intel
processor on 65 nm or 90 nm process or an MMBT3904 transistor. Using the Remote Diode Model Select
register found in the LM95234 any of the four remote inputs can be optimized for a typical Intel processor on 65
nm or 90 nm process or an MMBT3904.
+3.3V
Standby
C3
10 PF
C2
0.1 PF
C1*
100 pF
C4**
100 pF
Ambient
Board
Q1
MMBT3904
C5**
100 pF
Q2
MMBT3904
Processor
ASIC
C6**
100 pF
1
NC
2
VDD
3
D4+
4
D3+
5 D6 D2+
7 D1+
R1
10k
R2 R3
10k 10k
14
TCRIT3
13
SMBCLK
12
SMBDAT
11
TCRIT2
10
TCRIT1
9
A0
8
GND
R4
1.3k
R5
1.3k
SMBCLK
SMBDAT
SMBus
Master
LM95214
C7**
100 pF
* Note, place close to LM95214 pins.
** Note, optional - place close to LM95214 pins.
Figure 25. Typical Application
38
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Typical Application (continued)
8.2.1 Design Requirements
The LM95214 operates only as a slave device and communicates with the host through the SMBus serial
interface essentially compatible with I2C. SMBCLK is the clock input pin, SMBDATA is a bidirectional data pin,
and TCRIT1, TCRIT2, TCRIT3 are the output pins. The LM95214 requires a pullup resistor on the SMBCLK,
SMBDATA, and TCRIT1, TCRIT2, TCRIT3 pins due to an open-drain output. It is very important to consider the
pullup resistor for the I2C systems. The recommended value for the pullup resistors is in Figure 25. Use a
ceramic capacitor type with a temperature rating from –40°C to +125°C, placed as close as possible to the VDD
pin of the LM95214. The decoupling capacitor reduces any noise induced by the system. A0 (pin 6) can be
connected to either Low, Mid-Supply or High voltages for address selection for configuring three possible unique
slave ID addresses; SMBus Interface explains the addressing scheme.
8.3 Diode Non-Ideality
8.3.1 Diode Non-Ideality Factor Effect on Accuracy
When a transistor is connected as a diode, the following relationship holds for variables VBE, T and IF:
ª §KVxBEV · º
IF = IS x «e© t ¹ -1»
«
¬
»
¼
where
Vt =
•
•
•
•
•
•
•
•
kT
q
q = 1.6 × 10−19 Coulombs (the electron charge)
T = Absolute Temperature in Kelvin
k = 1.38 × 10−23 joules/K (Boltzmann's constant)
η is the non-ideality factor of the process the diode is manufactured on
IS = Saturation Current and is process dependent
If = Forward Current through the base-emitter junction
VBE = Base-Emitter Voltage drop
(1)
In the active region, the –1 term is negligible and may be eliminated, yielding Equation 2
IF = IS x
ª §KVxBEV ·º
«e© t¹»
«
»
¬
¼
(2)
In Equation 2, η and IS are dependant upon the process that was used in the fabrication of the particular diode.
By forcing two currents with a very controlled ratio(IF2 / IF1) and measuring the resulting voltage difference, it is
possible to eliminate the IS term. Solving for the forward voltage difference yields the relationship:
I F2
kT ·
x ln § ·
q
© ¹ © I F1¹
'VBE = K x §
(3)
Solving Equation 3 for temperature yields:
T=
q x 'VBE
§ IF2 ·
¸
© IF1 ¹
K x k x ln ¨¨
(4)
Equation 4 holds true when a diode connected transistor such as the MMBT3904 is used. When this diode
equation is applied to an integrated diode such as a processor transistor with its collector tied to GND as shown
in Figure 26 it will yield a wide non-ideality spread. This wide non-ideality spread is not due to true process
variation but due to the fact that Equation 4 is an approximation.
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Diode Non-Ideality (continued)
Texas Instruments invented TruTherm beta cancellation technology that uses the transistor equation, Equation 5,
which is a more accurate representation of the topology of the thermal diode found in some sub-micron FPGAs
or processors.
T=
q x 'VBE
§I ·
K x k x ln¨¨ C2 ¸
© IC1 ¹
(5)
7
IE = IF
D1+
100 pF
ASIC
IC IR
5
MMBT3904
IR
100 pF
D-
6
IF
D2+
LM95214
Figure 26. Thermal Diode Current Paths
TruTherm technology can be found in the LM95234 four channel remote diode sensor that is pin and register
compatible with the LM95214. The LM95214 does not support this technology.
8.3.2 Calculating Total System Accuracy
The voltage seen by the LM95214 also includes the IFRS voltage drop of the series resistance. The non-ideality
factor, η, is the only other parameter not accounted for and depends on the diode that is used for measurement.
Because ΔVBE is proportional to both η and T, the variations in η cannot be distinguished from variations in
temperature. Because the non-ideality factor is not controlled by the temperature sensor, it will directly add to the
inaccuracy of the sensor. For the for Intel processor on 65 nm process, Intel specifies a +4.06%/−0.897%
variation in η from part to part when the processor diode is measured by a circuit that assumes diode equation,
Equation 4, as true. As an example, assume a temperature sensor has an accuracy specification of ±1.0°C at a
temperature of 80°C (353 Kelvin) and the processor diode has a non-ideality variation of +1.19%/−0.27%. The
resulting system accuracy of the processor temperature being sensed will be:
TACC = + 1.0°C + (+4.06% of 353 K) = +15.3°C
and
TACC = –1.0°C + (−0.89% of 353 K) = –4.1°C
The next error term to be discussed is that due to the series resistance of the thermal diode and printed-circuit
board traces. The thermal diode series resistance is specified on most processor data sheets. For the
MMBT3904 transistor, this is specified at 0 Ω typical. The LM95214 accommodates the typical series resistance
of a circuit with the offset register compensation. The error that is not accounted for is the spread of the thermal
diodes series resistance. If a circuit has a series resistance spread that is 2.79 Ω to 6.24 Ω or 4.515 Ω ±1.73 Ω,
the 4.515 Ω can be cancelled out with the offset register setting. The ±1.73 Ω spread cannot be cancelled out.
The equation to calculate the temperature error due to series resistance (TER) for the LM95214 is simply:
ºC ·
§
TER = ¨0.62 : ¸ x RPCB
©
¹
(6)
Solving Equation 6 for RPCB equal to ±1.73 Ω results in the additional error due to the spread in the series
resistance of ±1.07°C. The bulk of the error caused by the 4.515 Ω will cause a positive offset in the temperature
reading of 2.79°C, which can be cancelled out by setting the offset register to –2.75°C. The spread in error
cannot be canceled out, as it would require measuring each individual thermal diode device. This is quite difficult
and impractical in a large volume production environment.
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Diode Non-Ideality (continued)
Equation 6 can also be used to calculate the additional error caused by series resistance on the printed circuit
board. Because the variation of the PCB series resistance is minimal, the bulk of the error term is always positive
and can simply be cancelled out by subtracting it from the output readings of the LM95214.
PROCESSOR FAMILY
DIODE EQUATION ηD, non-ideality
SERIES R,Ω
MIN
TYP
MAX
1
1.0065
1.0125
Pentium III CPUID 68h/PGA370Socket/
Celeron
1.0057
1.008
1.0125
Pentium 4, 423 pin
0.9933
1.0045
1.0368
Pentium 4, 478 pin
0.9933
1.0045
1.0368
Pentium 4 on 0.13 micron process, 2 - 3.06
GHz
1.0011
1.0021
1.0030
3.64
Pentium 4 on 90 nm process
1.0083
1.011
1.023
3.33
Pentium III CPUID 67h
Intel Processor on 65 nm process
Pentium M (Centrino)
1.000
1.009
1.050
4.52
1.00151
1.00220
1.00289
3.06
MMBT3904
1.003
AMD Athlon MP model 6
1.002
1.008
1.016
AMD Athlon 64
1.008
1.008
1.096
AMD Opteron
1.008
1.008
1.096
AMD Sempron
1.00261
0.93
8.3.3 Compensating for Different Non-Ideality
To compensate for the errors introduced by non-ideality, the temperature sensor is calibrated for a particular
processor. Texas Instruments temperature sensors are always calibrated to the typical non-ideality and series
resistance of a given transistor type. The LM95214 is calibrated for the non-ideality factor and series resistance
values of the MMBT3904 transistor without the requirement for additional trims. When a temperature sensor
calibrated for a particular thermal diode type is used with a different thermal diode type, additional errors are
introduced.
Temperature errors associated with non-ideality of different processor types may be reduced in a specific
temperature range of concern through use of software calibration. Typical Non-ideality specification differences
cause a gain variation of the transfer function, therefore the center of the temperature range of interest must be
the target temperature for calibration purposes. The Equation 7 can be used to calculate the temperature
correction factor (TCF) required to compensate for a target non-ideality differing from that supported by the
LM95214.
TCF =
§ KS - KPROCESSOR · x (TCR + 273K)
KS
©
¹
where
•
•
•
ηS = LM95214 non-ideality for accuracy specification
ηPROCESSOR = Processor thermal diode typical non-ideality
TCR = center of the temperature range of interest in °C
(7)
The correction factor must be directly added to the temperature reading produced by the LM95214. For example
when using the LM95214, with the 3904 mode selected, to measure a AMD Athlon processor, with a typical nonideality of 1.008, for a temperature range of 60°C to 100°C the correction factor would calculate to:
TCF =
§1.003 - 1.008 · ˜ (80 + 273) = -1.75oC
© 1.003 ¹
(8)
Therefore, 1.75°C must be subtracted from the temperature readings of the LM95214 to compensate for the
differing typical non-ideality target.
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9 Power Supply Recommendations
The LM95214 operates on a power-supply range from 3.0 V to 3.6 V. A power-supply bypass capacitor is
required, which much be placed as close as possible to the supply and ground pins of the device. A typical value
for this supply bypass capacitor is 100 nF. Applications with noisy or high-impedance power supplies may require
additional decoupling capacitors to reject power-supply noise.
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10 Layout
10.1 Layout Guidelines
In a noisy environment, such as a processor mother board, layout considerations are very critical. Noise induced
on traces running between the remote temperature diode sensor and the LM95214 can cause temperature
conversion errors. Keep in mind that the signal level the LM95214 is trying to measure is in microvolts. The
following guidelines must be followed:
1. VDD must be bypassed with a 0.1-µF capacitor in parallel with 100 pF. The 100-pF capacitor must be placed
as close as possible to the power supply pin. A bulk capacitance of approximately 10 µF must be in the near
vicinity of the LM95214.
2. Ti recommends the use of a 100-pF diode bypass capacitor to filter high-frequency noise, but it may not be
necessary. Make sure the traces to the 100-pF capacitor are matched. Place the filter capacitors close to the
LM95214 pins.
3. Ideally, the LM95214 must be placed within 10 cm of the Processor diode pins with the traces being as
straight, short and identical as possible. Trace resistance of 1 Ω can cause as much as 0.62°C of error. This
error can be compensated by using simple software offset compensation.
4. Diode traces must be surrounded by a GND guard ring to either side, above and below if possible. This GND
guard must not be between the D+ and D− lines. In the event that noise does couple to the diode lines it
would be ideal if it is coupled common mode. That is equally to the D+ and D− lines.
5. Avoid routing diode traces in close proximity to power supply switching or filtering inductors.
6. Avoid running diode traces close to or parallel to high-speed digital and bus lines. Diode traces must be kept
at least 2 cm apart from the high-speed digital traces.
7. If it is necessary to cross high-speed digital traces, the diode traces and the high-speed digital traces must
cross at a 90 degree angle.
8. The ideal place to connect the LM95214's GND pin is as close as possible to the Processors GND
associated with the sense diode.
9. Leakage current between D+ and GND and between D+ and D− must be kept to a minimum. Thirteen nanoamperes of leakage can cause as much as 0.2°C of error in the diode temperature reading. Keeping the
printed-circuit board as clean as possible will minimize leakage current.
Noise coupling into the digital lines greater than 400 mVp-p (typical hysteresis) and undershoot less than 500 mV
below GND, may prevent successful SMBus communication with the LM95214. SMBus no acknowledge is the
most common symptom, causing unnecessary traffic on the bus. Although the SMBus maximum frequency of
communication is rather low (100 kHz maximum), care still needs to be taken to ensure proper termination within
a system with multiple parts on the bus and long printed-circuit board traces. An RC lowpass filter with a 3-dB
corner frequency of about 40 MHz is included on the LM95214's SMBCLK input. Additional resistance can be
added in series with the SMBDAT and SMBCLK lines to further help filter noise and ringing. Minimize noise
coupling by keeping digital traces out of switching power supply areas as well as ensuring that digital lines
containing high-speed data communications cross at right angles to the SMBDAT and SMBCLK lines.
10.2 Layout Example
Figure 27. Ideal Diode Trace Layout
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11 Device and Documentation Support
11.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
11.2 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.3 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.4 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
11.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
44
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM95214CISD/NOPB
ACTIVE
WSON
NHL
14
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 140
95214CI
LM95214CISDX/NOPB
ACTIVE
WSON
NHL
14
4500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 140
95214CI
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of