TMP107

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SBOS716B – MAY 2015 – REVISED SEPTEMBER 2015

7.3 Feature Description

7.3.1 Digital Temperature Output

The 14-bit digital output from each temperature measurement conversion is stored in the temperature register.

Read two bytes to obtain the data. Table 1 summarizes the temperature data format. Negative numbers are

represented in binary twos complement format. The temperature sensor resolution is 0.015625ºC/LSB.

Table 1. Temperature Data Format

DIGITAL OUTPUT

TEMPERATURE (°C)

BINARY

HEX

127.984

01 1111 1111 1111

1FFF

100

01 1001 0000 0000

1900

80

01 0100 0000 1000

1408

75

01 0010 1100 0000

12C0

50

00 1100 1000 0000

C80

25

00 0110 0100 0000

640

0.25

00 0000 0001 0000

10

0

00 0000 0000 0000

0

–0.25

11 1111 1111 0000

3FF0

–25

11 1001 1100 0000

39C0

–55

11 0010 0100 0000

3240

Use the following rules to obtain the data for a given temperature, and vice versa.

•

To convert positive temperatures to a digital data format:

Divide the temperature by the resolution. Then, convert the result to binary code with a 14-bit, left-justified

format.

Example: (50°C) / (0.015625°C / LSB) = 3200 = C80h = 00 1100 1000 0000 = C80h

•

To convert a positive digital data format to temperature:

Convert the 14-bit, left-justified, binary temperature result to a decimal number. Then, multiply the decimal

number by the resolution to obtain the positive temperature.

Example: 00 1100 1000 0000 = C80h = 3200 × (0.015625°C / LSB) = 50°C

•

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 14-

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

number and adding one.

Example: (|–25°C|) / (0.015625°C / LSB) = 1600 = 640h = 00 0110 0100 0000

Twos complement format: 11 1001 1011 1111 + 1 = 11 1001 1100 0000 = 39C0h

•

To convert a negative digital data format to temperature:

Generate the twos complement of the 14-bit, left-justified binary number of the temperature result by

complementing the binary number and adding one. This number is the binary representation of the absolute

value of the temperature. Convert to a decimal number and multiply by the resolution to obtain the absolute

temperature, then multiply by –1 for the negative sign.

Example: 11 1001 1100 0000 has a twos complement of 00 0110 0011 1111 + 1 = 00 0110 0100 0000

Convert to temperature: 00 0110 0100 0000 = 640h = 1600; 1600 × (0.015625°C / LSB) = 25°C = (|–25°C|);

(|–25°C|) × (–1) = –25°C

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