I need a voltage reference(1.5V). so, i designed reference circuit.
(*refer to attached file)
I'm wondering that this circuit is right operation or not. because vdsat is about 55mV but (vgs-vth) is -50mV so i think this Transistor is in triode region. therefore in my opnion, this circuit is not work. how do you think about that?
What accuracy do you need? There are 3 pin regulators available from Microchip that are 1v5 at 1% tolerance. You could also use a TLV431 (low voltage version programmable zener) with programming resistors.
this circuit can be generated constant voltage. Of cause, there are differential amplifier after this circut. it is only used voltage reference for regulator.
I think all transistors are in saturation. Just check ur question. Vdsat=Vgs-Vth. Vds should be greater than Vdsat in order to keep transistor in saturation. Here all transistors have Vds greater than Vdsat. so all are in saturation.
you can find this annotation function in ADE (Analog Design Enviroment)
just select as below
* ADE -> Results> Annotate > DC operating points
what does that mean "area device can work" ?
thank you.
Added after 6 minutes:
satyasiva said:
I think all transistors are in saturation. Just check ur question. Vdsat=Vgs-Vth. Vds should be greater than Vdsat in order to keep transistor in saturation. Here all transistors have Vds greater than Vdsat. so all are in saturation.
as you see NMOS (M219, M218), vgs=623mV, vth=695mV
vgs-vth=-72mV , that is minus so i think it is in triode region.
and then , when i check the TR operation region using ADE's calculation fuction,
3 is displayed.
(where, number mean 0,3= triode region
2= saturation region)
* this TR's channel length is 10um, therefore this is not short channel length.
why vds ands vgs-vth is not equal? I used TSMC 0.18um process (1P6M)