two questions regarding op amp

[bemad]

two questions ?

Hi everybody

I have two questions

the left figure below shows a differential amplifier with a battery of voltage Vc in the feedback loop. amplifier operates in subthreshold regime. can someone help me for three different values of Vc (say Vc = 0V, 1V, and 3V, for instance), and sweep Vin from ground to +6V, tell me how would cicuit behave?. (Vout vs. Vin)? also for a fixed Vin=5.5V, and sweeping Vc from ground to 4V how would Vout vs. Vc, look like ?


the figure on right shows the amplifier circuit which is used for tunneling/injection. The inputs to the differential amplifier are gates of nFET transistors; therefore the transistor’s gate is part of the floating gate. The circuit is fabricated with the same polysilicon gate completely surrounded by SiO2, and hence, does not have any direct electrical connection with anything. how dpes this cicuit work for tunneling/injection?

i think the answer to questions above might overlap
can any body introduce a reference for studying such circuits for such application?
thanx in advance.

 

[Diffu]

Re: two questions ?

Hi
For the ckt in left side.
The voltage (Vo-Vc) can be considered as the feedback voltage. So the amp will have a gain of Vo/(Vo-Vc).
When you varry the input, the output will follow the input with a slope of Vo/(Vo-Vc).

For variuos Vc voltages various gains results. Let me know if this is wrong

I have no idea on right side ckt