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TMP108

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SBOS663A – APRIL 2013 – REVISED SEPTEMBER 2019

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Table 6. Byte 2 of Temperature Register

D7

D6

D5

D4

D3

D2

D1

D0

T3

T2

T1

T0

0

0

0

0

(1)

The temperature sensor ADC resolution is 0.0625°C/count.

Table 7. Temperature Data Format(1)

TEMPERATURE (°C)

DIGITAL OUTPUT

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

0000 0000 0000

000

–0.25

1111 1111 1100

FFC

–25

1110 0111 0000

E70

–55

1100 1001 0000

C90

Table 7 does not supply a full list of all temperatures. Use the following rules to obtain the digital data format for

a given temperature.

To convert positive temperatures to a digital data format:

Divide the temperature by the resolution. Then, convert the result to binary code with a 12-bit, left-justified

format, and MSB = 0 to denote a positive sign.

Example: (+50°C)/(0.0625°C/count) = 800 = 320h = 0011 0010 0000

To convert negative temperatures to a digital data format:

Divide the absolute value of the temperature by the resolution, and convert the result to binary code with a

12-bit, left-justified format. Then, generate the twos complement of the result by complementing the binary

number and adding one. Denote a negative number with MSB = 1.

Example: (|–25°C|)/(0.0625°C/count) = 400 = 190h = 0001 1001 0000

Twos complement format: 1110 0110 1111 + 1 = 1110 0111 0000

7.5.3 Configuration Register

The configuration register is a 16-bit read and write register used to store bits that control the operational modes

of the temperature sensor. Read and write operations are performed MSB first. The format and power-up (reset)

default value of the configuration register is shown in Table 8, followed by an explanation of the register bits.

Other options for the default values are available by request.

Table 8. Configuration and Power-Up/Reset Format

BYTE

D7

D6

D5

D4

D3

D2

D1

D0

1

ID

CR1

CR0

FH

FL

TM

M1

M0

0

0

1

0

0

0

1

0

2

POL

0

HYS1

HYS0

0

0

0

0

0

0

0

1

0

0

0

0

7.5.3.1 Hysteresis Control (HYS1 and HYS0)

When operating in comparator mode, the hysteresis control bits (HYS1 and HYS0) configure the hysteresis for

the limit comparison of the TMP108 to 0°C, 1°C, 2°C, or 4°C. The default hysteresis is 1°C. Table 9 shows the

settings for HYS1 and HYS0.