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Charge/Substrate pump for ESD protection??

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MPANDEJEE

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what do u mean by charge pump and substrate pump for ESD protection?
When and why is it used and also can anybody explain it using a simple circuit example..
its urgent

Thank you
 

ESDSolutions

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Hi Mpandejee

A substrate pump is used to ensure uniform triggering of the parasitic bipolar NPN inside NMOS devices.

For instance if you are using silicided (no foundry rules) output drivers then a substrate pump circuit can be used to ensure that all device fingers are conducting the ESD current uniformly.

People like Polgreen, Chatterjee, Amerasekera and Duvvury have reported about these approaches in the early 90-ties. Such substrate pump will locally (middle of the NMOS) increase the voltage of the substrate.

A paper that you can use as a starting point with references to other relevant papers was written by Duvvury from Texas Instruments in 2000. ("Substrate pump NMOS for ESD protection applications" - https://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=890022)

A charge pump can be used for disabling ESD protection during normal operation. For instance you could use an ESD protection transistor that is turned on unless its gate is biased highly positive (beyond Vdd) or negative.

I hope this helps you further...

ES
 

snafflekid

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ESDSolutions said:
A charge pump can be used for disabling ESD protection during normal operation. For instance you could use an ESD protection transistor that is turned on unless its gate is biased highly positive (beyond Vdd) or negative.

Thanks for the discussion. ESD is always trouble for me too

When would this be used? The ESD I used have snapback voltages above the power supply voltage
 

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