zhangljz
Member level 5
Hello,
For nmos, usually guard ring is connected to a separate and quiet GND. But in this case, the source and bulk are not at the same potential. So there will be body effect that has influence on vth. So the guard ring reduces substrate noise, but increases body effect, am I right?
For analog design(like a PLL), if the current is very small, say less than 1mA. Is it okey to short guard ring and nmos source, or separate them ?
Any advice is appreciated.
For nmos, usually guard ring is connected to a separate and quiet GND. But in this case, the source and bulk are not at the same potential. So there will be body effect that has influence on vth. So the guard ring reduces substrate noise, but increases body effect, am I right?
For analog design(like a PLL), if the current is very small, say less than 1mA. Is it okey to short guard ring and nmos source, or separate them ?
Any advice is appreciated.