Hi there,
In advance sorry for my bad English, besides that i'm studying physics so i'm not very well into electronics.


For a project within my traineeship, i need an PMOS inverter (and eventually a PMOS NAND-gate). As far as i understood, logically thinking about the Pchannel MOSFET as a switch, with gate 'high' being conductive and gate 'low' being non-conductive. I created the following circuit in MultiSim:




Adding an alternating block voltage of 4V gives the following graph, which suits for an inverter:


Though when i apply a DC voltage of e.g. 0.5 V on the input signal, it gives an output of 0 V. So the PMOS is only non-conductive when the input is exactly 0 Volts. Which is not suitable for logic as an input of 0.5 V still should be 'detected' as a 'low' input.
Could anyone help me fixing this problem? would love it.

 

See

 

Thanks a lot for your fast response. I made the same circuit in spice as you did, and it worked! Im developing an RFID tag and i'm going to use thin film materials for the whole circuit. Right now i'm working on a ring oscillator. I have an example of a CMOS ring oscillator, but i can only use PMOS for some reasons.

I thought i could develop a simple ring oscillator with just the circuit as below:


anyways i'm not getting any oscillatory behaviour. Could you think of a reason why?

 

Hello,

When you want to make a ring oscillator, they are made from an odd number of gates.
See these images for info:
https://images.search.yahoo.com/sea...wNzYw--?p=cmos+"ring+oscillator"&fr=altavista

Bertus

 

Yes i know, i've already done some research in it. Eventually i will allow phase differences on the outputs and maybe add capacitors. But even when i'm usin gan odd number of gates i get the following below. I guess i'm doing something wrong but i don't know...



Really like this webpage, fast responses. I'm very grateful.

 

See

 

Do you think you can help me mimicing your circuit above? For example how to use the A[1]-----------------A[11] function? google won't help me...

 

Figured it out, thanks a lot guys!