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Latch-up in AD7376 digital potentiometer

Question asked by asmcoder on Oct 23, 2012
Latest reply on Oct 25, 2012 by asmcoder

Hi all,

 

We are getting latch-up in the AD7376ARWZ10 digital pot which we run off +/-15V supplies.

There are short periods (200ms) where the VDD & VSS (+/-15V) supplies are not powered fully and yet signals are being input to the device : either 5 V logic signals, or the A,W,B inputs.

 

To reduce the problem Im trying to limit the current of the incoming signals. Is there a maximum current that the chip can handle without going into latch-up when the rails are not fully powered ? eg: 20mA.

 

Or is latch-up purely determined by the voltage at a point in time eg: even a very current limited signal greater than the rail will/may cause latch-up.?

Is there a typical limit ?

 

As I have to retro fit a fix, I am looking for simple fixes before we change the design to totally resolve the issue.

 

Thanks for any help.

Regards,

Colin

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