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resistor between source and gate of ESD device?

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castrader

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what is its use?
to protect the ESD device stand high current?
and what about its value?
 

castrader said:
what is its use?
to protect the ESD device stand high current?
and what about its value?
Click to expand...

------------------------------------------
its about 1k-10k the value
 

No, it's just about hundreds ohm, less than 1K.
And usually it is N diffuse resistor.
 

I think when large current flow the ESD device, Cgd and this resistor will give a path for current, so that ESD device will be protected.
 

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    castrader

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also i have seen in some ESD I/O, use linear MOSFET instead the resistor, is it same?
 

Alan_Nesta said:
I think when large current flow the ESD device, Cgd and this resistor will give a path for current, so that ESD device will be protected.
Click to expand...

I think the reason is when there is a large pulse, it will be coupled to the gate of the ggnmos and there will be current flow through the res between g and s , then settles up a voltage Vgs to decrease the breakdown voltage of the ggnos. So the discharge will be more effective.
 

then why 0 Ohm connect is worse than a fixed resistor?
 

sharpsheep said:
Alan_Nesta said:
I think when large current flow the ESD device, Cgd and this resistor will give a path for current, so that ESD device will be protected.
Click to expand...

I think the reason is when there is a large pulse, it will be coupled to the gate of the ggnmos and there will be current flow through the res between g and s , then settles up a voltage Vgs to decrease the breakdown voltage of the ggnos. So the discharge will be more effective.
Click to expand...


I agree with you, Ming-Dou Ker 's papers is a good reference
 

sharpsheep said:
Alan_Nesta said:
I think when large current flow the ESD device, Cgd and this resistor will give a path for current, so that ESD device will be protected.
Click to expand...

I think the reason is when there is a large pulse, it will be coupled to the gate of the ggnmos and there will be current flow through the res between g and s , then settles up a voltage Vgs to decrease the breakdown voltage of the ggnos. So the discharge will be more effective.
Click to expand...

True, or more specifically, the resistor build up a voltage drop instantaneously so that the the built-in current/discharge path, usually a diode-connected MOS or PNPN works first, and hence protects the other circuits.
 

several hundred to several K ohm

it can flow some current to protect
 

It's about hundreds ohm, and seems poly res is more used.
 

I remember 30Kohm is recommended in the book "ESD in IC".
 

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