shaq said:Dear all,
Is it important that phase margin of opamp in bandgap reference?
And, I want to know what is the most important of opamp in bandgap reference.
Plz give me more suggestions.
Thanks so much!!!!
winsonpku said:i don't think phase margin is important for the opamp used in bandgap.
because bandgap is almost a dc circuit and dc gain and offset of the opamp maybe more important.
Hi
First of all, for all systems with feedback to work properly, they should be stable otherwise you want an oscillator or something like that!
For the case of bandgap, dc gain, offset and PSRR are all very important parameters besides stability concerns.
Hope it helps!
regards,
jordan76
jordan76 said:winsonpku said:i don't think phase margin is important for the opamp used in bandgap.
because bandgap is almost a dc circuit and dc gain and offset of the opamp maybe more important.
Hi
First of all, for all systems with feedback to work properly, they should be stable otherwise you want an oscillator or something like that!
For the case of bandgap, dc gain, offset and PSRR are all very important parameters besides stability concerns.
Hope it helps!
regards,
jordan76
Thanks for your suggestion!!!
iocx said:Phase margin is an important parameter to opamp. If you don't design well, the opamp will oscillate.AZ can reduce offset voltage.
eng_Semi said:Don't care with the PM of the opamp BUT take care of the PM of the loop
shaq said:iocx said:Phase margin is an important parameter to opamp. If you don't design well, the opamp will oscillate.AZ can reduce offset voltage.
Dear iocx,
What is "AZ" ?
shaq said:Here, I have a little quetion that is how to minimize the vos of opamp in the bandgap reference circuit.
ipsc said:shaq said:Here, I have a little quetion that is how to minimize the vos of opamp in the bandgap reference circuit.
Same techniques that apply to opamp also apply for Bandgap.
Some of them:
1. common centroid layout for input diff-pair
2. Low VDsat for input diff-pair.
3. Sizing of 2nd-stage input TR. & 1st stage load TRs in the ratio of their currents.
Regards
khaled fayed said:Hi All
when u r supplying RF circuits that are sensitive to noise u should consume larger current in the BG opamp to minimize the output noise.
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