LM95172
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SNOSB33B – DECEMBER 2009 – REVISED MARCH 2013
LM95172 13-Bit to 16-Bit 200°C Digital Temp Sensor with 3-Wire Interface
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FEATURES
1
•
2
•
•
•
•
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•
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LM95172EWG is AEC-Q100 Grade 0 Qualified
and is Manufactured on an Automotive Grade
Flow.
13-Bit (0.0625°C LSB) to 16-Bit (0.0078125°C
LSB) Temperature Resolution
Wide −40°C to +200°C Temperature Range
35 ms Best Conversion Time Tracks Fast
Temp Changes
OVERTEMP Digital Output Switches
when TDIE > THIGH
Shutdown Mode Saves Power yet Wakes up
for One-Shot Temperature Update
SPI and MICROWIRE Bus Interface
10-Pin Cerpack High-Temperature Ceramic
Package
APPLICATIONS
•
•
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Automotive High Temperature Applications
Industrial Power Controllers
Industrial Motors, Gear Boxes
Geothermal Instrumentation
High Temperature Test Equipment
KEY SPECIFICATIONS
•
•
•
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Analog and Digital Supply Voltage 3.0V to 5.5V
Total Supply Current
Operating 400 µA
(typ)
– Shutdown −40°C to +140°C 4 µA (max)
– Shutdown −40°C to +175°C 12 µA (max)
– Shutdown −40°C to +200°C 28 µA (max)
Temperature Accuracy
– +175°C to +200°C ±3.0°C (max)
– +130°C to +160°C ±1.0°C (max)
– +120°C to +130°C ±2.0°C (max)
– +160°C to +175°C ±2.0°C (max)
– −40°C to +120°C ±3.5°C (max)
Temperature Resolution
– 13-bit mode 0.0625°C/LSB
– 16-bit mode 0.0078125°C/LSB
•
Conversion Time
– 13-bit mode 43 ms (max)
– 16-bit mode 350 ms (max)
DESCRIPTION
The LM95172EWG is an integrated digital-output
temperature sensor with a Serial Peripheral Interface
(SPI) and MICROWIRE™-compatible interface in a
10-pin Cerpack high temperature ceramic package. It
features a very linear Sigma-Delta Analog-to-Digital
Converter (ADC), high accuracy, fast conversion
rates, and extremely low output noise. With an
operating temperature as low as -40°C and optimized
accuracy from 120°C to 200°C, it is ideal for hightemperature applications.
The over-temperature alarm output (OVERTEMP)
asserts when the die temperature exceeds a
programmed THIGH limit. The user-programmed TLOW
limit creates a temperature-stabilizing hysteresis
when the ambient temperature is near the trip point.
The LM95172EWG can be programmed to operate
from 13 bits (0.0625°C per LSB) to 16 bits
(0.0078125°C
per
LSB)
resolution.
The
LM95172EWG powers up in 35 ms, the fastest
conversion time, with temperature output set at 13-bit
resolution. The resolution may then be changed to
14-, 15- or 16-bits. When in the 13-, 14- or 15-bit
resolution mode, the least significant bit in the 16-bit
temperature register toggles after the completion of
each conversion. This bit may be monitored to verify
that the conversion is complete.
The high noise immunity of the Serial I/O (SI/O)
output makes the LM95172EWG ideal for use in
challenging electromagnetic environments.
Connection Diagram
1
10
VDD IO
SC
2
9
VDD ANALOG
NC
3
8
NC
CS
4
7
SI/O
GND
5
6
NC
OVERTEMP
LM95172EWG
Figure 1. LM95172EWG- Top View
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2009–2013, Texas Instruments Incorporated
LM95172
SNOSB33B – DECEMBER 2009 – REVISED MARCH 2013
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PIN DESCRIPTIONS
Pin
Number
Name
Type
1
OVERTEMP
Output
2
SC
3
4
Description
Typical Connection
OVERTEMP Alarm
Over-temperature Alarm Output, Open-drain. Active Low on
POR. Requires a pull-up resistor to VDD IO.
Input
Serial Clock input
Serial clock from the Controller
NC
N/A
No Connect
Do not connect to this pin.
CS
Input
Chip Select input
Chip Select input for the bus. Low pass filtered.
5
GND
Ground
Power Supply Ground
Ground
6
NC
No Connect
Do not connect to this pin.
N/A
Bidirection
Serial I/O
al
7
SI/O
8
NC
N/A
9
VDD ANALOG
10
VDD IO
Serial I/O Data line to or from the Controller
No Connect
Do not connect to this pin.
Power
Analog Power Supply
Voltage
DC Voltage from 3.0V to 5.5V. Bypass with a 10 nF ceramic
capacitor near the pad to ground.
Power
Digital Power Supply
Voltage
DC Voltage from 3.0V to 5.5V. Bypass with a 10 nF ceramic
capacitor near the pin to ground.
Simplified Block Diagram
VDD ANALOG
VDD IO
3.0V to 5.5V
9
3.0V to 5.5V
10
Temperature
Sensor
Circuitry
13- to 16-Bit
Sigma-Delta
A/D Converter
LM95172EWG
1
OVERTEMP
Temperature Manufacturer's
Control/Status
Temperature
High/Low Limit
Register and Logic
ID Register
Register
Registers
7
CS
4
Three-Wire
Serial Interface
2
SI/O
SC
5
2
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Typical Application
3.0 to 5.5 Volts
VDD IO
VDD IO
VDD ANALOG
RPULL-UP
10k
CS
Microcontroller
OVERTEMP
SC
LM95172EWG
SI/O
GND
OVERTEMP
GND
Figure 2. Microcontroller Interface - normal connection
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings
(1)
−0.2V to 6.0V
VDD ANALOG and VDD IO Supply Voltages
−0.2V to (VDD IO + 0.2V)
Voltage at any Pin
Input Current at any Pin
5 mA
−65°C to +175°C
Storage Temperature
Soldering Information
Infrared or Convection
(20 sec.)
235°C
ESD Susceptibility (2)
Human Body Model
Machine Model
Charged Device Model
(1)
(2)
2500 V
250 V
1000 V
“Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur, including inoperability and degradation of
device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or
other conditions beyond those indicated in the Operating Ratings is not implied. The Operating Ratings indicate conditions at which the
device is functional and the device should not be operated beyond such conditions.
Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin. The
Charged Device Model (CDM) is a specified circuit characterizing an ESD event that occurs when a device acquires charge through
some triboelectric (frictional) or electrostatic induction processes and then abruptly touches a grounded object or surface.
Operating Ratings
Specified Temperature Range
−40°C to +200°C
Analog Supply Voltage Range
VDD ANALOG
+3.0V to +5.5V
Digital Supply Voltage Range
VDD IO
+3.0V to +5.5V
Package Thermal Resistances
Package
θJA
10-Lead CERPACK
175°C/W
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Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for VDD ANALOG = VDD IO = 3.0V to 3.6V. (1)Boldface limits apply for TA
=−40°C to +200°C; all other limits TA = 25°C, unless otherwise noted.
Parameter
Temperature
Accuracy (1)
Conditions
Typical
(2)
TA = +175°C to +200°C
±3.0
TA = +130°C to +160°C
±1.0
TA = +120°C to +130°C
±2.0
TA = +160°C to +175°C
±2.0
TA = −40°C to +120°C
±3.5
13
0.0625
Bits
°C
0
1
14
0.03125
Bits
°C
1
0
15
0.015625
Bits
°C
1
1
16
0.0078125
Bits
°C
For 13 Bits Resolution
43 (5)
For 14 Bits Resolution
87 (5)
For 15 Bits Resolution
175 (5)
For 16 BIts Resolution
350 (5)
Bus Inactive
Continuous Conversion Mode
Shutdown Mode
400
TA = −40°C to
175°C
TA = −40°C to
200°C
Total Quiescent
Current (6)
510
500
TA = −40°C to
175°C
12
28
TA = −40°C to 175°C
TA = −40°C to 200°C
(4)
(5)
(6)
4
650
4
TA = −40°C to 140°C
(3)
ms (max)
456
TA = −40°C to
140°C
TA = −40°C to
200°C
(1)
(2)
°C (max)
Res 0 Bit
0
TA = −40°C to
140°C
Power-On Reset
Threshold
Units
(Limit)
Res 1 Bit
0
Resolution
Temperature
Conversion
Time (4)
LM95172EWG
Limits (3)
μA (max)
75
0.9
V (min)
2.1
V (max)
0.8
V (min)
2.1
V (max)
0.3
V (min)
2.1
V (max)
The LM95172EWG will operate properly over the VDD ANALOG = 3.0V to 5.5V and VDD IO = 3.0V to 5.5V supply voltage ranges.
Typical values represent most likely parametric norms at specific conditions (Example Vcc; specific temperature) and at the
recommended Operating Conditions at the time of product characterizations and are not ensured.
The Electrical characteristics tables list ensured specifications under the listed Operating Ratings except as otherwise modified or
specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not ensured.
This specification is provided only to indicate how often temperature data is updated. The LM95172EWG can be read at any time
without regard to conversion state (and will yield last conversion result). A conversion in progress will not be interrupted. The output shift
register will be updated at the completion of the read and a new conversion restarted.
Specification is ensured by characterization and is not tested in production
Total Quiescent Current includes the sum of the currents into the VDD ANALOG and the VDD IO pins.
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Logic Electrical Characteristics Digital DC Characteristics
Unless otherwise noted, these specifications apply for VDD ANALOG = VDD IO = 3.0V to 3.6V.
40°C to 200°C; all other limits TA = +25°C, unless otherwise noted.
Symbol
Parameter
VIH
Logical "1" Input Voltage
VIL
Logical "0" Input Voltage
VHYST
Conditions
Digital Input Hysteresis
IIH
Logical “1” Input Leakage Current
IIL
Logical “0” Input Current
VOH
Output High Voltage
VOL
Output Low Voltage
OVERTEMP Output Saturation Voltage
(1)
(2)
(3)
(1)
. Boldface limits apply for TA = -
Typical
(2)
Limits
(3)
Units (Limit)
0.75×VDD IO
V (min)
0.25×VDD IO
V (max)
VDD IO = 3.0V
0.63
0.42
V (min)
VDD IO = 3.3V
0.79
0.56
VDD IO = 3.6V
0.97
0.72
VDD IO = 4.5V
0.9
VDD IO = 5.0V
1.0
VDD IO = 5.5V
1.1
VIN = VDD IO
1
μA (max)
VIN = 0V
−1
μA (max)
IOH = 100 μA (Source)
VDD IO − 0.2
V (min)
IOH = 2 mA (Source)
VDD IO −
0.45
IOL = 100 μA (Sink)
0.2
IOL = 2 mA (Sink)
0.45
IOL = 2 mA (Sink)
0.45
V (max)
V(max)
The LM95172EWG will operate properly over the VDD ANALOG = 3.0V to 5.5V and VDD IO = 3.0V to 5.5V supply voltage ranges.
Typical values represent most likely parametric norms at specific conditions (Example Vcc; specific temperature) and at the
recommended Operating Conditions at the time of product characterizations and are not ensured.
The Electrical characteristics tables list ensured specifications under the listed Operating Ratings except as otherwise modified or
specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not ensured.
Serial Bus Digital Switching Characteristics
Unless otherwise noted, these specifications apply for VDD ANALOG = VDD IO = 3.0V to 3.6V (1); CL (load capacitance) on output
lines = 100 pF unless otherwise specified. Boldface limits apply for TA = -40°C to 200°C; all other limits TA = +25°C, unless
otherwise noted.
Symbol
(1)
(2)
(3)
(4)
(5)
Parameter
t1
SC (Serial Clock) Period
t2
CS (Chip Select) Low to SC High Set-Up Time
t3
CS Low to SI/O Output Delay
t4
t5
Typical
(2)
Limits
(3)
Units
(Limit)
765
ns (min)
1.25
µs (min)
1
µs (max)
SC Low to SI/O Output Delay
120
ns (max)
CS High to Data Out (SI/O) TRI-STATE
220
ns (max)
t6
SC High to SI/O Input Hold Time
50
ns (min)
t7
SI/O Input to SC High Set-Up Time
30
ns (min)
(4) (5)
(4) (5)
t8
SC Low to CS High Hold Time
50
ns (min)
tTA
Data Turn-Around Time: SI/O input (write to LM95172EWG) to output (read from
LM95172EWG)
130
ns (max)
tBUF
Bus free time between communications: CS High to CS Low (4) (5)
5
µs (min)
The LM95172EWG will operate properly over the VDD ANALOG = 3.0V to 5.5V and VDD IO = 3.0V to 5.5V supply voltage ranges.
Typical values represent most likely parametric norms at specific conditions (Example Vcc; specific temperature) and at the
recommended Operating Conditions at the time of product characterizations and are not ensured.
The Electrical characteristics tables list ensured specifications under the listed Operating Ratings except as otherwise modified or
specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not ensured.
Specification is ensured by characterization and is not tested in production
Specification is ensured by design and is not tested in production
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CS
t2
SC
tr
t1
t4
t3
tf
t4
SI/O
Output
Figure 3. Data Output Timing Diagram
CS
CS
SC
SC
t5
SI/O
Output
t5
SI/O
Output
Figure 4. TRI-STATE Data Output Timing Diagram
CS
CS
t8
t8
SC
SC
t7
t7
t6
t6
SI/O
Input
SI/O
Input
Figure 5. Data Input Timing Diagram
tBUF
CS
Figure 6. tBUF Timing Definition Diagram
tTA
SI/O
Output
SI/O
Input
Figure 7. tTA Timing Definition Diagram
6
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Figure 8. TRI-STATE Test Circuit
VDD IO
IOL = 1.6 mA
LM95172QA2
Pad 10
SI/O
1.4V
C1
80 pF
IOH = -1.6 mA
LM95172QA2
Pad 8
GND
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FUNCTIONAL DESCRIPTION
The LM95172EWG temperature sensor incorporates a temperature sensor and a 13-bit to 16-bit ΣΔ ADC
(Sigma-Delta Analog-to-Digital Converter). Compatibility of the LM95172EWG's three wire serial interface with
SPI and MICROWIRE allows simple communications with common microcontrollers and processors. Shutdown
mode can be used to optimize current drain for different applications. A Manufacturer's/Device ID register
identifies the LM95172EWG as Texas Instruments product. See Figure 9.
CS
SC
Interface
SI/O
Data
Address
Pointer Register
(selects register
for communication)
Temperature (Read-Only)
Default Register
Control/Status
(Read-Write)
Pointer = 81h (r), 01h (w)
THIGH
(Read-Write)
Pointer = 82h (r), 02h (w)
TLOW
(Read-Write)
Pointer = 83h (r), 03h (w)
Identification
(Read-Only)
Pointer = 87h
Figure 9. LM95172EWG Functional Block Diagram
INITIAL SOFTWARE RESET AND POWER-UP SEQUENCES AND POWER ON RESET (POR)
Software Reset Sequence
A software reset sequence must be followed, after the initial VDD ANALOG and VDD IO supply voltages reach their
specified minimum operating voltages, in order to ensure proper operation of the LM95172EWG.
The software reset sequence is as follows:
1. Allow VDD ANALOG and VDD IO to reach their specified minimum operating voltages, as specified in Operating
Ratings, and in a manner as specified in Power-Up Sequence.
2. Write a “1” to the Shutdown bit, Bit 15 of the Control/Status Register, and hold it high for at least the
specified maximum conversion time for the initial default of 13-bits resolution, in order to ensure that a
complete reset operation has occurred. (See the Temperature Conversion Time specifications within
Temperature-to-Digital Converter Characteristics.)
3. Write a “0” to the Shutdown bit to restore the LM95172EWG to normal mode.
4. Wait for at least the specified maximum conversion time for the initial default of 13-bits resolution in order to
ensure that accurate data appears in the Temperature Register.
8
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Power-Up Sequence
WARNING
In all cases listed below the VDD
IOwaveform
ANALOG
waveform must not lag the VDD
Linear Power-up In the case where the VDD ANALOG and VDD IO voltage-vs.-time function is linear, the specified
minimum operating voltage must be reached in 5 ms or less.
Resistor-Capacitor (R-C) Charging Exponential Power-up In the case where the VDD ANALOG and VDD IO
voltage-vs.-time function is as a typical R-C Charging exponential function the time constant must be less
than or equal to 1.25 ms.
Other Power-up Functions In the case where the VDD ANALOG and VDD IO voltage-vs.-time characteristic follows
another function the following requirements must be met:
1. The specified minimum operating voltage values for VDD ANALOG and VDD IO must be reached in 5 ms or less.
2. The slope of the VDD ANALOG and VDD IO power-up curves must be greater than or equal to 0.7 V/ms at any
time before the specified minimum operating voltage is reached.
3. The slope of the VDD ANALOG and VDD IO power-up curves must not allow ringing such that the voltage is
allowed to drop below the specified minimum operating voltage at any time after the specified minimum
operating voltage is reached.
Power On Reset (POR)
After the requirements of Software Reset Sequence and Power-Up Sequence are met each register will then
contain its defined POR default value. Any of the following actions may cause register values to change from
their POR value:
1. The master writes different data to any Read/Write (R/W) bits, or
2. The LM95172EWG is powered down.
The specific POR Value of each register is listed in INTERNAL REGISTER STRUCTURE.
ONE SHOT CONVERSION
The LM95172EWG features a one-shot conversion bit, which is used to initiate a singe conversion and
comparison cycle when the LM95172EWG is in shutdown mode. While the LM95172EWG is in shutdown mode,
writing a "1" to the One-Shot bit in the Control/Status Register will cause the LM95172EWG to perform a single
temperature conversion and update the Temperature Register and the affected status bits. Operating the
LM95172EWG in this one-shot mode allows for extremely low average-power comsumption, making it ideal for
low-power applications.
When the One-shot bit is set, the LM95172EWG initiates a temperature conversion. After this initiation, but
before the completion of the conversion, and resultant register updates, the LM95172EWG is in a "one-shot"
state. During this state, the Data Available (DAV) flag in the Control/Status Register is "0" and the Temperature
Register contains the value 8000h (-256°C). All other registers contain the data that was present before initiating
the one-shot conversion. After the temperature measurement is complete, the DAV flag will be set to "1" and the
temperature register will contain the resultant measured temperature.
OVERTEMP OUTPUT
The Over-temperature (OVERTEMP) output is a temperature switch signal that indicates when the measured
temperature exceeds the THIGH programmed limit. The programmable THIGH register sets the high temperature
limit and the TLOW register is used to set the hysteresis. The TLOW register also sets the temperature below which
the OVERTEMP output resets. The OVERTEMP output of the LM95172EWG behaves as a temperature
comparator. The following explains the operation of OVERTEMP. Figure 10 illustrates the OVERTEMP output
behavior.
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OVERTEMP Reset
%LW VHW WR ³1´
THIGH Limit
Measured
Temperature
TLOW Limit
OVERTEMP Output
Polarity = Active Low
Up to 1 Conversion Time
1 Conversion Time
NOTE: The OVERTEMP output asserts when the measured temperature is greater than the THIGH value.
Figure 10. LM95172EWG OVERTEMP vs. Temperature Response Diagram
The OVERTEMP Output will assert when the measured temperature is greater than the THIGH value.
OVERTEMP will reset if any of the following events happen:
1. The temperature falls below the value stored in the TLOW register, or
2. A "1" is written to the OVERTEMP Reset bit in the Control/Status Register.
If OVERTEMP is cleared by the master writing a "1" to the OVERTEMP Reset bit while the measured
temperature still exceeds the THIGH value, OVERTEMP will assert again after the completion of the next
temperature conversion. Placing the LM95172EWG in shutdown mode or triggering a one-shot conversion does
not cause OVERTEMP to reset.
COMMUNICATING WITH THE LM95172EWG
The serial interface consists of three lines: CS (Chip Select), SC (Serial Clock), and the bi-directional SI/O (Serial
I/O) data line. A high-to-low transition of the CS line initiates the communication. The master (processor) always
drives the chip select and the clock. The first 16 clocks shift the temperature data out of the LM95172EWG on
the SI/O line (a temperature read). Raising the CS at anytime during the communication will terminate this read
operation. Following this temperature read, the SI/O line becomes an input and a command byte can be written
to the LM95172EWG. This command byte contains a R/W bit and the address of the register to be
communicated with next (see INTERNAL REGISTER STRUCTURE). When writing, the data is latched in after
every 8 bits. The processor must write at least 8 bits in order to latch the data. If CS is raised before the falling
edge of the 8th command bit, no data will be latched into the command byte. If CS is raised after the 8th bit, but
before the 16th bit, of a write to a 16-bit data register, only the most significant byte of the data will be latched.
This command-data-command-data sequence may be performed as many times as desired.
CS
1
16
SC
D16
SI/O
D0
Temperature Reg Read
(16 bits)
Figure 11. Reading the Temperature Register
10
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CS
1
16
1
D0
P7
8
1
16
P0
D16
SC
D16
Temperature Reg Read
(16 bits)
SI/O
Command Byte
Write (8 bits)
D0
Data Register
Read or Write (16 bits)
Figure 12. Reading the Temperature Register followed by a read or write from another register
(Control/Status, THIGH, TLOW, or Identification register)
CS
1
16
1
8
1
16
1
8
1
16
P7
P0
D16
SC
D16
D0
Temperature Reg Read
(16 bits)
SI/O
P7
P0
Command Byte
Write (8 bits)
D16
D0
Data Register
Read or Write (16 bits)
Command Byte
Write (8 bits)
D0
Data Register
Read or Write (16 bits)
Figure 13. Reading the Temperature Register followed by repeated commands and Data Register
accesses (Control/Status, THIGH, TLOW, or Identification register)
TEMPERATURE DATA FORMAT
Temperature data is represented by a 13- to 16-bit, two's complement word with a Least Significant Bit (LSB)
equal to 0.0625 °C (13-bits), 0.03125 °C (14-bits), 0.015625 °C (15-bits) or 0.0078125 °C (16-bits). See
Temperature Register for definition of the bits in the Temperature Register.
Table 1. 13-Bit Resolution. First Bit (D15) is Sign, the last bit (D0) is Toggle and bits D1 and D2 are
always 0.
13-bit Resolution Digital Output
Temperature
+175°C
+150°C
+80°C
+25°C
+0.0625°C
0°C
−0.0625°C
16-bit Binary
All 16 Bits
Bits D15 - D3
Hex
Hex
0101011110000 000
5780
0101011110000 001
5781
0100101100000 000
4B00
0100101100000 001
4B01
0010100000000 000
2800
0010100000000 001
2801
0000110010000 000
0C80
0000110010000 001
0C81
0000000000001 000
0008
0000000000001 001
0009
0000000000000 000
0000
0000000000000 001
0001
1111111111111 000
FFF8
1111111111111 001
FFF9
0AF0
0960
0500
0190
0001
0000
1FFF
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Table 1. 13-Bit Resolution. First Bit (D15) is Sign, the last bit (D0) is Toggle and bits D1 and D2 are
always 0. (continued)
13-bit Resolution Digital Output
Temperature
−40°C
16-bit Binary
All 16 Bits
Bits D15 - D3
Hex
Hex
1110110000000 000
EC00
1110110000000 001
EC01
1D80
Table 2. 14-Bit Resolution. First bit (D15) is Sign, the last bit (D0) is Toggle and bit D1 is always 0.
14-bit Resolution Digital Output
Temperature
+175°C
+150°C
+80°C
+25°C
+0.03125°C
0°C
−0.03125°C
−40°C
16-bit Binary
All 16 Bits
Bits D15 - D2
Hex
Hex
01010111100000 00
5780
01010111100000 01
5781
01001011000000 00
4B00
01001011000000 01
4B01
00101000000000 00
2800
00101000000000 01
2801
00001100100000 00
0C80
00001100100000 01
0C81
00000000000001 00
0004
00000000000001 01
0005
00000000000000 00
0000
00000000000000 01
0001
11111111111111 00
FFFC
11111111111111 01
FFFD
11101100000000 00
EC00
11101100000000 01
EC01
15E0
12C0
0A00
0320
0001
0000
3FFF
3B00
Table 3. 15-Bit Resolution. First bit (D15) is Sign and the last bit (D0) is Toggle.
15-bit Resolution Digital Output
Temperature
+175°C
+150°C
+80°C
+25°C
+0.015625°C
0°C
−0.015625°C
−40°C
12
16-bit Binary
All 16 Bits
Bits D15 - D1
Hex
Hex
010101111000000 0
5780
010101111000000 1
5781
010010110000000 0
4B00
010010110000000 1
4B01
001010000000000 0
2800
001010000000000 1
2801
000011001000000 0
0C80
000011001000000 1
0C81
000000000000001 0
0002
000000000000001 1
0003
000000000000000 0
0000
000000000000000 1
0001
111111111111111 0
FFFE
111111111111111 1
FFFF
111011000000000 0
EC00
111011000000000 1
EC01
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2BC0
2580
1400
0640
0001
0000
7FFF
7600
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Table 4. 16-Bit Resolution. First bit (D15) is Sign and the last bit (D0) is the LSB.
16-bit Resolution Digital Output
Temperature
All 16 Bits
16-bit Binary
Hex
+175°C
0101 0111 1000 0000
5780
+150°C
0100 1011 0000 0000
4B00
+80°C
0010 1000 0000 0000
2800
+25°C
0000 1100 1000 0000
0C80
+0.0078125°C
0000 0000 0000 0001
0001
0°C
0000 0000 0000 0000
0000
−0.0078125°C
1111 1111 1111 1111
FFFF
−40°C
1110 1100 0000 0000
EC00
The first data byte is the most significant byte with most significant bit first, permitting only as much data as
necessary to be read to determine temperature condition. For instance, if the first four bits of the temperature
data indicate an overtemperature condition, the host processor could immediately take action to remedy the
excessive temperatures.
SHUTDOWN MODE
Shutdown Mode is enabled by writing a “1” to the Shutdown Bit, Bit 15 of the Control/Status Register, and
holding it high for at least the specified maximum conversion time at the existing temperature resolution setting.
(see Temperature Conversion Time specifications under the Temperature-to-Digital Converter Characteristics).
For example, if the LM95172EWG is set for 16-bit resolution before shutdown, then Bit 15 of the Control/Status
register must go high and stay high for the specified maximum conversion time for 16-bits resolution.
The LM95172EWG will always finish a temperature conversion and update the temperature registers before
shutting down.
Writing a “0” to the Shutdown Bit restores the LM95172EWG to normal mode.
INTERNAL REGISTER STRUCTURE
The LM95172EWG has four registers that are accessible by issuing a command byte (a R/W Bit plus the register
address: Control/Status, THIGH, TLOW, and Identification. Which of these registers will be read or written is
determined by the Command Byte. See COMMUNICATING WITH THE LM95172EWG for a complete
description of the serial communication protocol. The following diagram describes the Command Byte and lists
the addresses of the various registers. On power-up, the Command Byte will point to the Temperature Register
by default. The temperature is read by lowering the CS line and then reading the 16-Bit temperature register; all
other registers are accessed by writing a Command Byte after reading the temperature.
All registers can be communicated with, either in Continuous Conversion mode or in Shutdown mode. When the
LM95172EWG has been placed in Shutdown Mode, the Temperature register will contain the temperature data
which resulted from the last temperature conversion (whether it was the result of a continuous-conversion
reading or a one-shot reading).
Command Byte
P7
P6
P5
P4
P3
R/W
0
0
0
0
P2
P1
P0
Register Select
Bit Read/Write Bit. Tells the LM95172EWG if the host will be writing to, or reading from, the register to which
this byte is pointing.
Bits Not Used. These Bits must be zero. If an illegal address is written, the LM95172EWG will return
0000h on the subsequent read.
Bits Pointer Address Bits. Points to desired register. See table below.
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P2
P1
P0
0
0
0
Register
0
0
1
Control/Status
0
1
0
THIGH
0
1
1
TLOW
1
0
0
1
0
1
1
1
0
1
1
1
Invalid.
Invalid.
(1)
(1)
Identification
Invalid. The LM95172EWG will return a "0" if read. If written to, no valid register will be modified.
Power-On Reset state: 00h
Reset Conditions: Upon Power-on Reset
Temperature Register
(Read Only): Default Register
D15
D14
D13
D12
D11
D10
D9
D8
Sign
128°C
64°C
32°C
16°C
8°C
4°C
2°C
D7
D6
D5
D4
D3
D2
D1
D0
1°C
0.5°C
0.25°C
0.125°C
0.0625°C
0.03125°C
0.015625°C
Conversion - Toggle/ 0.0078125°C
Bit : Temperature Data Byte. Represents the temperature that was measured by the most recent
temperature conversion in two's complement form. On power-up, this data is invalid until the DAV Bit in the
Control/Status Register is high (that is, after completion of the first conversion).
The resolution is user-programmable from 13-Bit resolution (0.0625°C) through 16-Bit resolution (0.0078125°C).
The desired resolution is programmed through Bits 4 and 5 of the Control/Status Register. See the description of
Control/Status Register for details on resolution selection.
The Bits not used for a selected resolution are always set to "0" and are not to be considered part of a valid
temperature reading. For example, for 14-Bit resolution, Bit is not used and, therefore, it is invalid and is
always zero.
Bit : Conversion Toggle or, if 16-Bit resolution has been selected, this is the 16-Bit temperature LSB.
When in 13-Bit, 14-Bit, or 15-Bit resolution mode, this Bit toggles each time the Temperature register is read if a
conversion has completed since the last read. If conversion has not completed, the value will be the same as the
last read.
When in 16-Bit resolution mode, this is the Least Significant Bit of the temperature data.
Reset Conditions: See Software Reset Sequence, Power-Up Sequence, and INITIAL SOFTWARE RESET AND
POWER-UP SEQUENCES AND POWER ON RESET (POR) for reset conditions.
One-Shot State: 8000h (-256°C)
Control/Status Register
(Read/Write) Pointer Address: 81h (Read); 01h (Write)
D15
D14
D13
D12
SD
One-Shot
OVERTEMP Reset
D11
Conversion Toggle OVERTEMP Status
D10
D9
D8
THIGH
TLOW
DAV
D7
D6
D5
D4
D3
D2
D1
D0
OVERTEMP Disable
OVERTEMP POL
RES1
RES0
0
reserved
reserved
0
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Bit : Shutdown (SD) Bit. Writing a “1” to this bit and holding it high for at least the specified maximum
conversion time, at the existing temperature resolution setting, enables the Shutdown Mode. Writing a “0” to this
bit restores the LM95172EWG to normal mode.
Bit : One-Shot Bit. When in shutdown mode (Bit is "1"), initiates a single temperature conversion and
update of the temperature register with new temperature data. Has no effect when in continuous conversion
mode (i.e., when Bit is "0"). Always returns a "0" when read.
Bit : OVERTEMP Reset Bit. Writing a "1" to this Bit resets the OVERTEMP Status bit and, after a possible
wait up to one temperature conversion time, the OVERTEMP pin. It will always return a "0" when read.
Bit : Conversion Toggle Bit. Toggles each time the Control/Status register is read if a conversion has
completed since the last read. If conversion has not been completed, the value will be the same as last read.
Bit : OVERTEMP Status Bit. This Bit is "0" when OVERTEMP output is low and "1" when OVERTEMP
output is high. The OVERTEMP output is reset under the following conditions: (1) Cleared by writing a "1" to the
OVERTEMP Reset Bit (Bit ) in this register or (2) Measured temperature falls below the TLOW limit. If the
temperature is still above THIGH, and OVERTEMP Reset is set to "1", then the Bit and the pin clear until the next
conversion, at which point the Bit and pin would assert again.
Bit : Temperature High (THIGH) Flag Bit. This Bit is set to "1" when the measured temperature exceeds the
THIGH limit stored in the programmable THIGH register. The flag is reset to "0" when both of two conditions are
met: (1) temperature no longer exceeds the programmed THIGH limit and (2) upon reading the Control/Status
Register. If the temperature no longer exceeds the THIGH limit, the status Bit remains set until it is read by the
master so that the system can check the history of what caused the OVERTEMP to assert.
Bit : Temperature Low (TLOW) Flag Bit. This Bit is set to "1" when the measured temperature falls below the
TLOW limit stored in the programmable TLOW register. The flag is reset to "0" when both of two conditions are met:
(1) temperature is no longer below the programmed TLOW limit and (2) upon reading the Control/Status Register.
If the temperature is no longer below, or equal to, the TLOW limit, the status Bit remains set until it is read by the
master so that the system can check the history of what caused the OVERTEMP to assert.
Bit : Data Available (DAV) Status Bit. This Bit is "0" when the temperature sensor is in the process of
converting a new temperature. It is "1" when the conversion is done. It is reset after each read and goes high
again after one temperature conversion is done. In one-shot mode: after initiating a temperature conversion while
operating, this status Bit can be monitored to indicate when the conversion is done. After triggering the one-shot
conversion, the data in the temperature register is invalid until this Bit is high (i.e., after completion of the first
conversion).
Bit : OVERTEMP Disable Bit. When set to "0" the OVERTEMP output is enabled. When set to "1" the
OVERTEMP output is disabled. This Bit also controls the OVERTEMP Status Bit (this register, Bit ) since
that Bit reflects the state of the OVERTEMP pin.
Bit : OVERTEMP Polarity Bit. When set to "1", OVERTEMP is active-high. When "0" it is active-low.
Control/Status Register (Continued)
Bit : Temperature Resolution Bits. Selects one of four user-programmable temperature data resolutions as
indicated in the following table.
Control/Status Register
Resolution
Bit 5
Bit 4
Bits
°C
0
0
13
0.0625
0
1
14
0.03125
1
0
15
0.015625
1
1
16
0.0078125
Bit : Always write a zero to this Bit.
Bit : Reserved Bits. Will return whatever was last written to them. Value is zero on power-up.
Bit : Always write a zero to this Bit.
Reset State: 0000h
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Reset Conditions: Upon Power-on Reset.
THIGH: Upper Limit Register
(Read/Write) Pointer Address: 82h (Read); 02h (Write)
D15
D14
D13
D12
D11
D10
D9
D8
Sign
128°C
64°C
32°C
16°C
8°C
4°C
2°C
D4
D3
D2
D1
D0
D7
D6
D5
1°C
0.5°C
0.25°C
Reserved
Bit : Upper-Limit Temperature byte. If the measured temperature, stored in the temperature register,
exceeds this user-programmable temperature limit, the OVERTEMP pin will assert and the THIGH flag in the
Control/Status register will be set to "1".
Bit : Reserved. Returns all zeroes when read.
Reset State: 4880h (+145°C)
Reset Conditions: Upon Power-on Reset.
TLOW: Lower Limit Register
(Read/Write) Pointer Address: 83h (Read); 03h (Write)
D15
D14
D13
D12
D11
D10
D9
D8
Sign
128°C
64°C
32°C
16°C
8°C
4°C
2°C
D7
D6
D5
D4
D3
D2
D1
D0
1°C
0.5°C
0.25°C
Reserved
Bit : Lower-Limit Temperature byte. If the measured temperature that is stored in the temperature register
falls below this user-programmable temperature limit, the OVERTEMP pin will not assert and the TLOW flag in the
Control/Status register will be set to "1".
Bit : Reserved. Returns all zeroes when read.
Reset State: 4600h (+140°C)
Reset Conditions: Upon Power-on Reset.
MFGID: Manufacturer, Product, and Step ID Register
(Read Only) Pointer Address: 87h
D15
D14
D13
D12
D11
D10
D9
D8
1
0
0
0
0
0
0
0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
1
1
0
0
0
0
Bit : Manufacturer Identification Byte. Always returns 80h to uniquely identify the manufacturer as Texas
Instruments Corporation.
Bit : Product Identification Nibble. Always returns 30h to uniquely identify this part as the LM95172EWG.
Bit : Die Revision Nibble. Returns 0h to uniquely identify the revision level as zero.
Reset State: 8030h
Reset Conditions: Upon Power-on Reset.
16
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SNOSB33B – DECEMBER 2009 – REVISED MARCH 2013
Typical Applications
+3.3 VDC
CS
GPI/O
RXD
INTEL 196
Microcontroller
100 nF
VDD IO
VDD ANALOG
10k
LM95172EWG
SI/O
OVERTEMP
SC
TXD
GND
OVERTEMP
Figure 14. Temperature monitor using Intel 196 processor
+3.3 VDC
VDD ANALOG
VDD IO
100 nF
CS
10k
GPI/O1
10k
GPI/O2
MSIO
68HC11
Microcontroller
SI/O
LM95172EWG
OVERTEMP
SC
SC
GND
OVERTEMP
Figure 15. LM95172EWG digital input control using microcontroller's general purpose I/O.
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REVISION HISTORY
Changes from Revision A (March 2013) to Revision B
•
18
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 17
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PACKAGE OPTION ADDENDUM
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28-Jan-2022
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)
LM95172EWG/NOPB
ACTIVE
CFP
NAC
10
54
RoHS-Exempt
& Green
SAC305
Level-1-NA-UNLIM
-40 to 200
LM95172
EWG
(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