TMP103

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SBOS545A

– FEBRUARY 2011 – REVISED MARCH 2011

Table 3. Temperature Register

TEMPERATURE REGISTER

D7

D6

D5

D4

D3

D2

D1

D0

The

Temperature

Register

of

the

TMP103

is

T7

T6

T5

T4

T3

T2

T1

T0

configured as an eight-bit, read-only register that

stores the output of the most recent conversion. A

Negative numbers are represented in binary twos

single byte must be read to obtain data, and is

complement format. Following power-up or reset, the

described in Table 3. The data format for temperature

Temperature Register reads 0

°C until the first

is summarized in Table 4. One LSB equals 1

°C.

conversion is complete.

TEMPERATURE (

°C)

DIGITAL OUTPUT (BINARY)

HEX

128

0111 1111

7F

127

0111 1111

7F

100

0110 0100

64

80

0101 0000

50

75

0100 1011

4B

50

0011 0010

32

25

0001 1001

19

0

0000 0000

00

–1

1111 1111

FF

–25

1110 0111

E7

–55

1100 1001

C9

(1)

The resolution for the ADC is 1

°C/count, where count is equal to the digital output of the ADC.

For positive temperatures (for example, +50

°C):

Twos complement is not performed on positive numbers. Therefore, simply convert the number to binary

code, left-justified format. Denote a positive number with MSB = '0'.

Example: (+50

°C)/(1°C/count) = 50 = 32h = 0011 0010

For negative temperatures (for example,

–25°C):

Generate the twos complement of a negative number by complementing the absolute value binary number

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

Example: (|

–25°C|)/(1°C/count) = 25 = 19h = 0001 1001

Twos complement format: 1110 0110 + 1 = 1110 0111

Copyright

© 2011, Texas Instruments Incorporated

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