APPLICATIONS INFORMATION
The TMP175 and TMP75 are digital temperature sensors
that are optimal for thermal management and thermal protec-
tion applications. The TMP175 and TMP75 are Two-Wire
and SMBus interface-compatible, and are specified over a
temperature range of –40°C to +125°C.
The TMP175 and TMP75 require no external components
for operation except for pull-up resistors on SCL, SDA, and
ALERT, although a 0.1µF bypass capacitor is recommended,
as shown in Figure 1.
Pointer
Register
Temperature
Register
Configuration
Register
SCL
I/O
Control
Interface
SDA
T
LOW
Register
V+
T
HIGH
Register
0.1µF
8
To
Two-Wire
Controller
SCL
SDA
2
1
TMP175
TMP75
7
6
5
3
4
A
0
A
1
A
2
ALERT
(Output)
P7
0
P6
0
P5
0
P4
0
P3
0
P2
0
P1
P0
FIGURE 2. Internal Register Structure of TMP175 and TMP75.
Register Bits
NOTE: SCL, SDA, and ALERT
pins require pull-up resistors.
GND
TABLE I. Pointer Register Byte.
P1
0
0
1
1
P0
0
1
0
1
REGISTER
Temperature Register (READ Only)
Configuration Register (READ/WRITE)
T
LOW
Register (READ/WRITE)
T
HIGH
Register (READ/WRITE)
FIGURE 1. Typical Connections of the TMP175 and TMP75.
The sensing device of the TMP175 and TMP75 is the chip
itself. Thermal paths run through the package leads as well
as the plastic package. The lower thermal resistance of metal
causes the leads to provide the primary thermal path.
To maintain accuracy in applications requiring air or surface
temperature measurement, care should be taken to isolate
the package and leads from ambient air temperature. A
thermally-conductive adhesive will assist in achieving accu-
rate surface temperature measurement.
TABLE II. Pointer Addresses of the TMP175 and TMP75
Registers.
TEMPERATURE REGISTER
The Temperature Register of the TMP175 or TMP75 is a
12-bit, read-only register that stores the output of the most
recent conversion. Two bytes must be read to obtain data,
and are described in Table III and Table IV. The first 12 bits
are used to indicate temperature, with all remaining bits equal
to zero. Data format for temperature is summarized in Table
V. Following power-up or reset, the Temperature Register will
read 0°C until the first conversion is complete.
D7
T11
D6
T10
D5
T9
D4
T8
D3
T7
D2
T6
D1
T5
D0
T4
POINTER REGISTER
Figure 2 shows the internal register structure of the TMP175
and TMP75. The 8-bit Pointer Register of the devices are
used to address a given data register. The Pointer Register
uses the two LSBs to identify which of the data registers
should respond to a read or write command. Table I identifies
the bits of the Pointer Register byte. Table II describes the
pointer address of the registers available in the TMP175 and
TMP75. Power-up Reset value of P1/P0 is 00.
TABLE III. Byte 1 of Temperature Register.
D7
T3
D6
T2
D5
T1
D4
T0
D3
0
D2
0
D1
0
D0
0
TABLE IV. Byte 2 of Temperature Register.
TMP175, 75
SBOS288C
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