Datasheet

Pointer Register
(selects register
for communication)
Interface
Data
Address
SI/O
SC
T
HIGH
(Read-Write)
Pointer = 82h (r), 02h (w)
T
LOW
(Read-Write)
Pointer = 83h (r), 03h (w)
Temperature (Read-Only)
Default Register
CS
Control/Status
(Read-Write)
Pointer = 81h (r), 01h (w)
Identification
(Read-Only)
Pointer = 87h
LM95172
SNOSB33B –DECEMBER 2009–REVISED MARCH 2013 www.ti.com
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.
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 V
DD ANALOG
and V
DD 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 V
DD ANALOG
and V
DD 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.
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