How to get a constant turn over theshold voltage of inverter

[walker5678]

I encountered a problem that require a constant turn over threshold voltage of an inverter over a supply voltage range of 5V ~ 2.5V, and the voltage is better to be 1.1V. For example, at vdd=2.5V, the voltage is 1.1V, and at vdd=5V, the voltage is about 1.2-1.3V.
Seems that it is difficult to achieve this goal. Could anyone give some advice?

thanks!

 

[mdcui]

theoratically, a CMOS process variation will prevent a simple inverter from having a constant trip point, so one of the easy way is to use a bandgap to generate a reference voltage and an inverter to compare your input signal against that reference voltage for a digital output, not sure if it fits for your circuit.

 

[Humungus]

Re: How to get a constant turn over theshold voltage of inve

Implement your inverter with a differential pair whose non-inverting input is tied to a reference of about 1.1 (your threshold) and the input signal sweeps the inverting input.

 

[DenisMark]

It's not possible to make constant trip point for inverter. If in ur process VthN~0.9V u can try to make nmos much more stronger than pmos so trip point will be close to ~1V for ur supply range.

 

[hung_wai_ming@hotmail.com]

It's IMPOSSIBLE for a SIMPLE inverter to work as what you want. Please sort out to use bandgap and comparator instead.

 

[alasliu]

you can use comparator or ldo to supply invertor