TMP112: Getting temp reading above 128C in 12-bit configuration

Swantika Dhundia

Part Number: TMP112
Other Parts Discussed in Thread: TMP117

Hello!

I need to use TMP112A sensor to measure temperatures upto 160C. The datasheet mentions that the sensor should be configured in 13-bit mode to read temperatures above 128C. I want to be able to read 160C temperatures in 12-bit mode itself (some communication format related constraint at my end). Is that possible? More specifically, what would the sensor output be (in 12-bit configuration) for 135C temperature (say)? Would it be 1000 0111 0000 or will there be no output at all?

Thanks,

Swantika

over 6 years ago

0 Amit Ashara over 6 years ago

TI__Guru**** 244400 points

Hello Swantika,

TMP112 has a Rated Free operating air temperature of -40 to +125C. So reading above +125C is anyways out of the question here as you would be outside the operating specification and at +160C, outside of the absolute maximum ratings as well.

We have some parts like the TMP117 which can go up to +150C, that you may want to consider

0 Ren Schackmann over 6 years ago

TI__Mastermind 43835 points

If you look at Table 2 on page 11 of the datasheet, you'll see that 12 bit output stops at 128C. This 12bit encoding scheme is very common across IC temperature sensor industry. Fundamentally, regardless of which sensor you choose, you will not be able to make temperature measurements above 128C when this type of 12 bit encoding is employed. The value will be railed at 128C. You will have to find a way to work around this constraint in your system.

Thanks,
Ren

0 Amit Ashara over 6 years ago

TI__Guru**** 244400 points

Hello Swantika,

Is there any further update or information from our side, that is required?

0 Swantika Dhundia over 6 years ago in reply to Ren Schackmann

Prodigy 80 points

Exactly what I wanted to know. Thanks for your help!

0 Swantika Dhundia over 6 years ago in reply to Amit Ashara

Prodigy 80 points

Thanks Amit! We have qualified TMP112A for temperatures above 125C for our application. Hence, wanted to know what the sensor output would be without going through the trouble of actually testing it out.

0 Swantika Dhundia over 6 years ago in reply to Amit Ashara

Prodigy 80 points

No. Thanks for your help!

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TMP112: Getting temp reading above 128C in 12-bit configuration