What is the difference between Guard ring and Substrate contacts ?

[vbhupendra]

what is the difference b/w Guard ring and Substrate contacts ? How many types of Guard Rings are possible ?

 

[Fom]

Re: Guard Ring

Two types of guard ring:
- P-type contact to GND
- N-type contact to VDD
Both of them should suppress parasitic tyristor structure to prevent latchup.

 

[Hughes]

Guard Ring

Guard ring may be P-Type substrate contact connected to GND or N-Well contact connected to VDD.
Guard rings are usually closed ring.
Guard ring may not be substrate/nwell contacts. A nwell ring may be a guard ring (minority guard ring)

 

[truebs]

Re: Guard Ring

Guard rings may also be used to isolate some sensitive part of circuit.

 

[mappycarol]

Guard Ring

Both of them can protect circuitry from latch-up. Guardring can also isolate sensitive analog from noisy digital circuit. And please note that sometimes double guard ring is need to implement for better protection.

 

[leeenghan]

Re: Guard Ring

Hi,

The following include notes on guard ring:

**broken link removed**

Page 20 to page 27.

Regards,
Eng Han

 

[chenjia]

Guard Ring

You can find more information about Guardring in book"the art of layout"