ADS1113 datasheet(21/50 Pages) TI2

21 / 50 page

ADS1118

www.ti.com

SBAS457F – OCTOBER 2010 – REVISED SEPTEMBER 2019

Product Folder Links: ADS1118

Submit Documentation Feedback

9.3.6 Temperature Sensor

The ADS1118 offers an integrated precision temperature sensor. The temperature sensor mode is enabled by

setting bit TS_MODE = 1 in the Config Register. Temperature data are represented as a 14-bit result that is left-

justified within the 16-bit conversion result. Data are output starting with the most significant byte (MSB). When

reading the two data bytes, the first 14 bits are used to indicate the temperature measurement result. One 14-bit

LSB equals 0.03125°C. Negative numbers are represented in binary twos complement format, as shown in

Table 4.

Table 4. 14-Bit Temperature Data Format

TEMPERATURE (°C)

DIGITAL OUTPUT (BINARY)

HEX

128

01 0000 0000 0000

1000

127.96875

00 1111 1111 1111

0FFF

100

00 1100 1000 0000

0C80

00 1001 0110 0000

0960

00 0110 0100 0000

0640

00 0011 0010 0000

0320

0.25

00 0000 0000 1000

0008

0.03125

00 0000 0000 0001

0001

00 0000 0000 0000

0000

–0.25

11 1111 1111 1000

3FF8

–25

11 1100 1110 0000

3CE0

–40

11 1011 0000 0000

3B00

9.3.6.1 Converting from Temperature to Digital Codes

For positive temperatures:

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

code in a 14-bit, left justified format with the MSB = 0 to denote the positive sign.

Example: 50°C / (0.03125°C/count) = 1600 = 0640h = 00 0110 0100 0000

For negative temperatures:

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

adding 1. Then denote the negative sign with the MSB = 1.

Example: |–25°C| / (0.03125°C/count) = 800 = 0320h = 00 0011 0010 0000

Twos complement format: 11 1100 1101 1111 + 1 = 11 1100 1110 0000

9.3.6.2 Converting from Digital Codes to Temperature

To convert from digital codes to temperature, first check whether the MSB is a 0 or a 1. If the MSB is a 0,

simply multiply the decimal code by 0.03125°C to obtain the result. If the MSB = 1, subtract 1 from the result

and complement all of the bits. Then multiply the result by –0.03125°C.

Example: The device reads back 0960h: 0960h has an MSB = 0.

0960h × 0.03125°C = 2400 × 0.03125°C = 75°C

Example: The device reads back 3CE0h: 3CE0h has an MSB = 1.

Subtract 1 and complement the result: 3CE0h

→ 0320h

0320h × (–0.03125°C) = 800 × (–0.03125°C) = –25°C

ADS1113 Datasheet(PDF) 21 Page - Texas Instruments

ADS1113 Datasheet(HTML) 21 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Datasheet Download

Link URL