Drive strength and threshold voltage

[jktstance]

Do low VT cells offer a higher drive strength than cells with higher VTs, all other parameters being equal? I want to say they do, even if it's a small gain, but I do not see a physical reason.

 

[YuLongHuang]

maybe the following current formula of transistor explain this:


this is the formula when MOSFET try to operate in linear mode and move to saturation.
for lower threshold voltage, the induced driving current increase faster than those with higher vt.
I think that it's the reason why the low threshold has better performance.

Regards,
Polo

 

[mehboobali]

Hi,
In CMOS circuits the drive strength is the Current Capability of the device i.e. Ids.

Ids can be increased by incresing the W/L ratio.

It is with this current the present state can drive the next stage i.e. charge the next stage capacitance.

Drive Strength: 1 / (effective resistance of gate)

M.ali