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Design >> Analog Design >> phase margin in opamp circuit
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Message started by Evgenii on Jun 15^th, 2009, 7:29am

Title: phase margin in opamp circuit
Post by Evgenii on Jun 15^th, 2009, 7:29am

Hi! :)
Cmos opamp (two-stage, repeater) has output on I/O pad. Complex capacitance of this pad may has different amount, say, 10-15pF. How to disable auto-oscillations of this repeater w/o using big internal cap... :(
Thanks!

Title: Re: phase margin in opamp circuit
Post by raja.cedt on Jun 15^th, 2009, 10:34am

hi,
what do you mean by repeater, could be please give some more information regarding your opamp?

Thanks,
rajasekhar.

Title: Re: phase margin in opamp circuit
Post by Evgenii on Jun 16^th, 2009, 1:30am

Hi!
Thanks for you reply!
attached repeater1.pdf
work ranges:
VDD (3 V-6V)
V_in (0.25 V - (VDD-2) V)
R_load (3KOhm - 300kOhm)
C_load (3-15pF)

I mean need in some cascode schematic... :(
Thanks.