Are there a different threshold voltages in an inverter?

[p_shinde]

consider an inverter, do p xsistor and n-xsistor has different threshold voltages??

thanks,
Prasad

 

[research235]

different threshold

hello shinde

i am back again in the lab,

there is a slight difference in turning on and off of NMOS and PMOS, for tech .25 and above the width of PMOS is more than that of NMOS, but this is in the case of a normal inverter .. and in general the is no difference in the absolute value, except for the sign .... in terms of quadrants .. VTC of a PMOS is in first quadrant and that of NMOS is in 3rd quadt...

suresh

 

[irfansyah]

Re: different threshold

yes, they do have different threshold voltages. nmos transistors have positive threshold voltage, whereas pmos have negative ones. their absolute values are different as well. you would normally have to refer to the datasheet for a certain technology, which differs from one foundry to the other.

Take for example, in the general design kit technology file from Cadence, particularly for the 90nm process, the 1V PMOS has a Vt of -140mV, whereas the 1V NMOS has a Vt of 170mV. The actual threshold value on different transistors placed on a chip will not be the same though, due to process variations.