How to measure the CMRR of an OPA on CADENCE tool?

[HAJER LAHIANI]

If some one can help me, he should tell me how to mesure the CMRR of an OPA on CADENCE tool and is it nessecery to do the MONTE CARLO simulation?

 

[SergeyBondarev]

cmrr waveform

See the book of Allen, Holberg "CMOS analog circuit design". There exist the measurement procedure of the OPA and the correspondent circuit for CMRR measurement. (page 430)

 

[dewabantura]

Re: CMRR of OPA

Below is the excerpt of my CMRR simulation netlist using HSPICE and Cosmoscope


*******************************************************CMRR*****************************************************************

Xopamp In1 In2 Vdd Vss Vout opamp

VEP In2 Vout dc 2 AC 1

VEN In1 0 dc 2 AC 1


.options list node post
.op

.AC DEC 10 1hz 1G

.PRINT AC Vdb(Vout) Vp(Vout) Vdb(In1) Vp(In1)

.end


After running it in hspice, open the CMRR waveform using Cosmoscope. Then use Cosmoscope calculator to calculate and plot vin/IvoutI waveform.