TMP112: Wrong Temperature Register values

Gregory Calco

Part Number: TMP112

Hello!

We have problems with several tmp112 sensors. Temperature Register reading return values 7FF0 or 07FF. Other registers reading/writing works great (Configuration,TLow,THigh), but temp register always return 7FF0 or 7FF1 in EM. I found only one similar problem discussion with no solution:

If anyone have any ideas - please let me know!

Thanks in advance!

over 8 years ago

0 Gregory Calco over 8 years ago

Prodigy 50 points

EM=1, SD=1,OS=1 and result after conversion in temperature resigter is 74A1
:(

0 Ren Schackmann over 8 years ago

TI__Mastermind 43815 points

Please read all four registers after a power cycle and before performing any other communication then share that information here.

Thanks,
Ren

0 Gregory Calco over 8 years ago in reply to Ren Schackmann

Prodigy 50 points

0 7FF0
1 6080
2 4800
3 5000

0 Ren Schackmann over 8 years ago in reply to Gregory Calco

TI__Mastermind 43815 points

My sample reads
0x18B0
0x60A0
0x4B00
0x5000

The difference in Config Register is due to the AL bit which should be zero in your case for a temperature result which exceeds T High.

Did you mistake the B in the T Low register for an 8? The default value should be 0x4B00 corresponding to 75C. If not, can you repeat this and show me your waveform?

Is it safe to assume your device is not actually at or around 127C?

Ren

0 Gregory Calco over 8 years ago in reply to Ren Schackmann

Prodigy 50 points

0x4B00 of course, my mistake.
Device is actually at ~20C, not 127C :)
Look like AD converter or diode sensor damage (

0 Gregory Calco over 8 years ago in reply to Ren Schackmann

Prodigy 50 points

My first thought was overheating.
For now we check 5 modules, 2 with reflow profile with peak temp 240C for 10sec, and 3 with peak 210C/10sec with low temp solder paste.
Same 7FF0 in temp register.

0 Ren Schackmann over 8 years ago in reply to Gregory Calco

TI__Mastermind 43815 points

Can you confirm that all of your assemblies have the same issue?

Can you share schematic?

Ren

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TMP112: Wrong Temperature Register values