Hi all,

If i want to make a diode, i can use a MOS transistor and connect the gate to the drain. However, the diode turn on voltage will equal Vth. Is there a way to have a diode with a turn on voltage closer to zero in CMOS? thanks,
Aaron

yes using a low vt device if available...... and if your process has a Schottky Diode option thats even more cool....  (both though at the cost of the additional masks)

and of course you can size/bias a normal vth device to tweak its vth within reason (like utilsing short-channel effects or forward body biasing etc).

In some process, for example, TSMC. they provide native device which has the 0v Vth with no additional cost.
However, when you use MOS's diode connection, the I-V relationship is not as same as the real diode. for example, for a long-channel device, I=a*V^2 while in diode, I=e^(-v)....

Thanks for the advice.

Actually it would need to work up to 3 GHz...also, the comparator would need a lot of power. My idea was meant to save power

Anyway after thinking about it i realized the idea probably wouldn't work even if i had the diode so nvm

thanks,
Aaron