Electrostatic discharge protection on pull-up pin


I am posting this on behalf of a customer, David :

I need help using the digikey PN SESD7L5.0DT5GOSCT-ND

SESD7L5.0DT5G https://www.digikey.com/en/products/detail/onsemi/SESD7L5-0DT5G/9087727

A Digikey tech forum page on this topic includes this:

However, I don’t think this configuration will work for a PU pin, because the ground diode points directly to the pin.

Attached you will see my sketch of a MCU having a Pull-up pin (PU), connected in series with a 100 Ohm resister to a periodic switch to ground. I want to provide ElectroStatic Discharge (ESD) protection.

  1. Please confirm the sketch diodes are correctly orientated to achieve ESD protection.
  2. If correct, please sketch how I would wire the above part to achieve ESD protection.

Feel free to call me at 406-465-3357 if you have questions. Thank you!


Drawing referenced by the customer does not appear to be attached.

Anyhow, the general idea would be as per below. Diode will conduct in either a reverse or forward direction depending on polarity of applied ESD event relative to system ground. Depending on polarity of applied ESD event, diode will clamp voltage on signal line to something slightly above its rated reverse breakdown voltage, or slightly less than zero. These voltages are likely to be somewhat outside of prescribed limits for logic ICs, so a series resistor can be used to limit the current flow through the IC due to these residual excess voltages.