current mirror voltage drop

[flabbergastt]

Hi,

What is the best way to reduce the voltage drop of a MOSFET current mirror for both nMOS and pMOS? Would it be the same for a cascode current mirror or wide-swing current mirror?

thanks

 

[crutschow]

You are generally limited by the gate-source threshold voltage (Vgs(th)) so you want transistors that have a low threshold.

 

[kemiyun]

You are generally limited by the gate-source threshold voltage (Vgs(th)) so you want transistors that have a low threshold.

I don't completely object to this but I don't completely agree either. Yes Vth is important but in ideal case you'd be able to go beyond gate voltage by Vth (assuming you don't care about accuracy that much). I think the ultimate limit is how much you can reduce the overdrive voltage, I believe this is a more generalized statement. But I'm not sure if this is what he meant with voltage drop.