TMP117: I2C bus fails shortly after power on

Jamie Harvey

Part Number: TMP117

Hi,

When attempting to prototype with the TMP117, the device responds correctly for up to a minute before failing and pulling the SDA pin low (on the scale of 50-200 ohms). This persists through power cycles unless the device is given time to 'cool down'. We have witnessed similar behavior with all TMP117 chips received. Other I2C devices work without issue.

Any guidance on this issue would be appreciated.

Thanks,
Jamie Harvey

over 6 years ago

0 Amit Ashara over 6 years ago

TI__Guru**** 244400 points

Hello Jamie,

There are a lot of open questions here, e.g. Operational voltage , operational conditions, layout, configuration, etc that have not been addressed

So my line of debug would be

1. What is the I2C Pull Up resistor value, to what voltage rail it is connected.?
2. Is the I2C Bus noise free?
3. Can you please share schematic and layout of the board?
4., Did you check the I2C Bus transaction on a scope prior to the failure?

0 Mihail Gurevitch over 6 years ago in reply to Amit Ashara

TI__Prodigy 355 points

Can you measure the TMP117 the supply current. Please check it.

Also what is the value of pull-up resistor connected to Alert pin? (If any)

It looks like device become overheated. Use your less favorable finger and touch part when it stops response. You shouldn't feel any heat.

0 Amit Ashara over 6 years ago

TI__Guru**** 244400 points

Hello Jamie,

Any update on the issue?

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TMP117: I2C bus fails shortly after power on