she_long
Junior Member level 3
loop gain simulation
Hi all,
I use the normal pmos-input-two stage amp as a buffer, and use Spectre to do the AC analysis. When do the AC analysis, I add the ac signal to Vin+/Vin- like this -> Vin+: AC mag=1 AC phase=180 dc=2.5; Vin-:AC mag=1 AC phase=0 dc=2.5, Vdd=5V, In this condition, I got a AC gain, but the Vout|DC is not 2.5V, I think the output stage isn't in the saturation region. When the amp used as a buffer Vout|DC must be 2.5V, How do I make the Vout|dc=2.5?
A friends advise me that use a large inductor(1GH) and a large cap(1GF) to consist a feedback net to the Vin-, and add the AC signal to the Vin+ only. I've tried it, it worked, Vout|DC=2.5. Is it correct?
Thanks!
Hi all,
I use the normal pmos-input-two stage amp as a buffer, and use Spectre to do the AC analysis. When do the AC analysis, I add the ac signal to Vin+/Vin- like this -> Vin+: AC mag=1 AC phase=180 dc=2.5; Vin-:AC mag=1 AC phase=0 dc=2.5, Vdd=5V, In this condition, I got a AC gain, but the Vout|DC is not 2.5V, I think the output stage isn't in the saturation region. When the amp used as a buffer Vout|DC must be 2.5V, How do I make the Vout|dc=2.5?
A friends advise me that use a large inductor(1GH) and a large cap(1GF) to consist a feedback net to the Vin-, and add the AC signal to the Vin+ only. I've tried it, it worked, Vout|DC=2.5. Is it correct?
Thanks!