ADC084S021 Logic input undershoot

NAOKI AOYAMA

Guru 11215 points

Other Parts Discussed in Thread: ADC084S021

Hello,

Our customer uses the ADC084S021.

The customer check the logic input (SCLK,DIN,CS) and observe a undershoot as below.

peak voltage : -1.5V

occurrence time : less than 3ns

There is no series resistor. The customer does not use a long wire GND of the probe. (use GND attachment)

Does this undershoot cause the device damage instantly?

Of course, it is not guarantee. I want to know a practical case.

Best Regards,

Naoki Aoyama

over 10 years ago

0 NAOKI AOYAMA over 10 years ago

Guru 11215 points

Hello,

I think the ESD diode is ON.
Is it possible to response by 2nsec?

Regards,
Naoki Aoyama

0 Michael Stout over 10 years ago in reply to NAOKI AOYAMA

TI__Genius 16890 points

Hello,

Yes, this will turn on the internal ESD diode. Damage can occur if the current is too high for too long of a time.

The Abs Max spec is 10mA. We recommend that this current be kept much lower, <1mA. If you install a 1.5k resistor, the current will be at 1mA for the 1.5V overshoot.

The part should be ok with this resistor.

Mike

0 NAOKI AOYAMA over 10 years ago in reply to Michael Stout

Guru 11215 points

Hello Michael,

Thank you for your reply.
I will suggest the customer to install a resistor.

Thanks,

Naoki Aoyama

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ADC084S021 Logic input undershoot