TMP175, 75

SBOS288C

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5

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 0.1

µF bypass capacitor is recommended,

as shown in Figure 1.

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.

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.

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.

P7

P6

P5

P4

P3

P2

P1

P0

0

0

0

0

0

0

Register Bits

TABLE I. Pointer Register Byte.

P1

P0

REGISTER

0

0

Temperature Register (READ Only)

0

1

Configuration Register (READ/WRITE)

10

11

TABLE II. Pointer Addresses of the TMP175 and TMP75

Registers.

D7

D6

D5

D4

D3

D2

D1

D0

T11

T10

T9

T8

T7

T6

T5

T4

TABLE III. Byte 1 of Temperature Register.

D7

D6

D5

D4

D3

D2

D1

D0

T3

T2

T1

T0

0

0

0

0

TABLE IV. Byte 2 of Temperature Register.

FIGURE 2. Internal Register Structure of TMP175 and TMP75.

TMP175

TMP75

0.1

µF

V+

GND

4

3

7

8

ALERT

(Output)

A

0

6

A

1

5

A

2

2

1

SCL

SDA

To

Two-Wire

Controller

NOTE: SCL, SDA, and ALERT

pins require pull-up resistors.

I/O

Control

Interface

SCL

SDA

Temperature

Register

Configuration

Register

T

LOW

Register

T

HIGH

Register

Pointer

Register