LM86: Sometimes get minus temperature under room temperature

Jim Tsan

Part Number: LM86
Other Parts Discussed in Thread: DXP

Dear sir,

Sometimes, we get the remote temperature(RTHB_01h) of LM86 lower than zero. But our DUT is tested under room temperature.

Do you have any idea of this symptom?

Thanks!

over 5 years ago

0 David Vaseliou over 5 years ago

TI__Expert 6820 points

Hi Jim,

Can you send your schematic? Also, what value is the negative temperature reading?

Thanks,

0 Jim Tsan over 5 years ago in reply to David Vaseliou

Prodigy 115 points

Hi David,

Here is schematic of LM86.

For the negative temperature, the raw data of RTBH_01h had been observed is 0xEA or 0xD5 not a fixed value.

Thanks,

Jim

0 David Vaseliou over 5 years ago in reply to Jim Tsan

TI__Expert 6820 points

Hi Jim,

The schematic looks ok. What is being connected to the DXP/DXN pins? Can you send the rest of schematic showing the device you are monitoring? Also, are you using cabling for the DXP/DXN pins? Lastly, would you be able to send a oscilloscope waveform of the DXP/DXN pin. Noise on these lines can cause bad temperature readings.

Thanks,

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LM86: Sometimes get minus temperature under room temperature