UCC28780: ucc28780- ntc internally 7.4 ohms

robin gangopadhya18

Mastermind 6296 points

Part Number: UCC28780

Ulrich

We removed the controller- and measured NTC pin to be 3 7.4 Ohms.

Any idea on the ways this can happen:

1- ESD?

Then only on 1 pin?

2- somehow external circuitry applied higher than 7V?...kind of out of real possibility...there is no such circuitry in proximity.

3- Our choice of a resistor is not correct- one should use NTC?

We can find NTC right here where are doing all this work.. ...of old-style in penny size disk! Cannot get SMD before next week...

Any help/review/comment will be so helpful again.

robin

over 5 years ago

0 Ulrich Goerke over 5 years ago

TI__Mastermind 40580 points

Hi Robin,

I was replying to your earlier post when this one came in.

This indicates the IC was damaged somehow; ESD is a likely possibility, maybe from a charged soldering iron if it is not continuously grounded.
The IC is rated for +/-2kV human body model and to +/-500V charged device model.

The value or physical size of the NTC used will not cause such damage.

Regards,
Ulrich

0 robin gangopadhya18 over 5 years ago in reply to Ulrich Goerke

Mastermind 6296 points

Ulirch:

We started checking for ESD sources after reading your prompt review of the situation yesterday.

Wont take out another part to instal until we have verified the assembly area ESD safe.

thnx for pointing out ESD being #1 possibility.

-robin

0 Ulrich Goerke over 5 years ago in reply to robin gangopadhya18

TI__Mastermind 40580 points

Thank you, Robin,

I'll need to close this thread unless the issue comes up again, which I hope it will not, of course.

Regards,
Ulrich

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UCC28780: ucc28780- ntc internally 7.4 ohms