TMP175, 75

6

SBOS288C

www.ti.com

The user can obtain 9, 10, 11, or 12 bits of resolution by

addressing the Configuration Register and setting the reso-

lution bits accordingly. For 9-, 10-, or 11-bit resolution, the most

significant bits in the Temperature Register are used with the

unused LSBs set to zero.

CONFIGURATION REGISTER

The Configuration Register is an 8-bit read/write register

used to store bits that control the operational modes of the

temperature sensor. Read/write operations are performed

MSB first. The format of the Configuration Register for the

TMP175 and TMP75 is shown in Table VI, followed by a

breakdown of the register bits. The power-up/reset value of

the Configuration Register is all bits equal to 0.

FAULT QUEUE (F1/F0)

A fault condition is defined as when the measured tempera-

required to generate an alert may be programmed using the

fault queue. The fault queue is provided to prevent a false

alert as a result of environmental noise. The fault queue

requires consecutive fault measurements in order to trigger

to reaching the number of programmed consecutive faults

limit, the count is reset to 0. Table VII defines the number of

measured faults that may be programmed to trigger an alert

condition in the device.

TEMPERATURE

DIGITAL OUTPUT

(°C)

(BINARY)

HEX

128

0111 1111 1111

7FF

127.9375

0111 1111 1111

7FF

100

0110 0100 0000

640

80

0101 0000 0000

500

75

0100 1011 0000

4B0

50

0011 0010 0000

320

25

0001 1001 0000

190

0.25

0000 0000 0100

004

0.0

0000 0000 0000

000

–0.25

1111 1111 1100

FFC

–25

1110 0111 0000

E70

–55

1100 1001 0000

C90

–128

1000 0000 0000

800

TABLE V. Temperature Data Format.

F1

F0

CONSECUTIVE FAULTS

00

1

01

2

10

4

11

6

TABLE VII. Fault Settings of the TMP175 and TMP75.

CONVERSION TIME

R1

R0

RESOLUTION

(typical)

0

0

9 Bits (0.5°C)

27.5ms

0

1

10 Bits (0.25°C)

55ms

1

0

11 Bits (0.125°C)

110ms

1

1

12 Bits (0.0625°C)

220ms

TABLE VIII. Resolution of the TMP175 and TMP75.

Byte

D7

D6

D5

D4

D3

D2

D1

D0

1

OS

R1

R0

F1

F0

POL

TM

SD

TABLE VI. Configuration Register Format.

SHUTDOWN MODE (SD)

The Shutdown Mode of the TMP175 and TMP75 allows the

user to save maximum power by shutting down all device

circuitry other than the serial interface, which reduces current

consumption to typically less than 0.1

µA. Shutdown Mode is

enabled when the SD bit is 1; the device will shut down once the

current conversion is completed. When SD is equal to 0, the

device will maintain a continuous conversion state.

THERMOSTAT MODE (TM)

The Thermostat Mode bit of the TMP175 and TMP75 indicates

to the device whether to operate in Comparator Mode (TM = 0)

or Interrupt Mode (TM = 1). For more information on comparator

and interrupt modes, see the section, High and Low Limit

Registers.

POLARITY (POL)

The Polarity Bit of the TMP175 and TMP75 allows the user

to adjust the polarity of the ALERT pin output. If POL = 0, the

ALERT pin will be active LOW, as shown in Figure 3. For

POL = 1, the ALERT Pin will be active HIGH, and the state

of the ALERT Pin is inverted.

FIGURE 3. Output Transfer Function Diagrams.

Measured

Temperature

T

HIGH

T

LOW

TMP75/TMP175 ALERT PIN

(Comparator Mode)

POL = 0

TMP75/TMP175 ALERT PIN

(Interrupt Mode)

POL = 0

TMP75/TMP175 ALERT PIN

(Comparator Mode)

POL = 1

TMP75/TMP175 ALERT PIN

(Interrupt Mode)

POL = 1

Read

Read

Time

Read

CONVERTER RESOLUTION (R1/R0)

The Converter Resolution Bits control the resolution of the

internal Analog-to-Digital (A/D) converter. This allows the

user to maximize efficiency by programming for higher reso-

lution or faster conversion time. Table VIII identifies the

Resolution Bits and relationship between resolution and con-

version time.