TMP175
TMP75
www.ti.com
SBOS288J − JANUARY 2004 − REVISED DECEMBER 2007
APPLICATIONS INFORMATION
The TMP175 and TMP75 are digital temperature sensors
that are optimal for thermal management and thermal
protection 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)
Figure 2. Internal Register Structure of the
TMP175 and TMP75
P7
0
P6
0
P5
0
P4
0
P3
0
P2
0
P1
P0
Register Bits
NOTE: SCL, SDA, and ALERT
pins require pull−up resistors.
GND
Table 1. Pointer Register Byte
P1
0
0
1
1
P0
0
1
0
1
REGISTER
Temperature Register (READ Only)
Configuration Register (READ/WRITE)
TLOW Register (READ/WRITE)
THIGH 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 accurate surface temperature measurement.
Table 2. Pointer Addresses of the TMP175 and
TMP75
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 3 and Table 4. Note that byte 1
is the most significant byte, followed by byte 2, the least
significant byte. The first 12 bits are used to indicate
temperature, with all remaining bits equal to zero. The
least significant byte does not have to be read if that
information is not needed. Data format for temperature is
summarized in Table 5. 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 is 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 1 identifies the bits of the Pointer Register byte.
Table 2 describes the pointer address of the registers
available in the TMP175 and TMP75. Power-up reset
value of P1/P0 is 00.
Table 3. Byte 1 of Temperature Register
D7
T3
D6
T2
D5
T1
D4
T0
D3
0
D2
0
D1
0
D0
0
Table 4. Byte 2 of Temperature Register
5
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