why 200 ohm is used in ESD protection circuits?

Status
Not open for further replies.
L

lhlbluesky

Banned
Joined
Mar 30, 2007
Messages
558
Helped
5
Reputation
10
Reaction score
5
Trophy points
1,298
Location
china
Activity points
0
why 200 ohm?

in ESD protect circuit,why 200 ohm resistor is used?i mean,why is it not any other value,such as 1K,10 ohm etc.is there any reasons?
 

Re: why 200 ohm?

There is no rule to use 200 ohm. Your circuit has it, but it may be any other value.
It's a tradeoff between the advantages of
- a high resistance (force a very low current in case a ESD voltage spike enters)
- a low resistance (not too much voltage drop during its normal use)

In your case the designer made the tradeoff at 200 ohms for that particular circuit usage.
 
Re: why 200 ohm?

Vomit is right regarding the trade-off. Higher resistance can increase ESD robustness... BUT be sure to provide primary protection path for the ESD current. A resistor alone will not protect against ESD! A large resistor will ensure that ESD current searches for shunt paths with lower impedance.

Many leading foundries ask for a 200 ohm resistor between the bondpad and the sensitive (IO) circuits. Maybe this is where this value is coming from?

However high resistance at the pad reduces functional performance: speed and output voltage are reduced.
 

Re: why 200 ohm?

I would like to add something;

except what's said above, I think that the protection for CDM is need to be

considerated;if the resistor is too huge, then the second protectin for CDM will be

damaged
 

Re: why 200 ohm?

thanks, learns a lot
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…