Jan 6, 2005 #1 C chinito Full Member level 2 Joined Jul 5, 2004 Messages 128 Helped 11 Reputation 22 Reaction score 6 Trophy points 1,298 Activity points 1,204 about CMRR of an op-amp I have designed opamp with Av ~ 80dB, PSRR+ = 87dB etc. I don't know how to plot CMRR. Could someone explain the setup. Thanks.
about CMRR of an op-amp I have designed opamp with Av ~ 80dB, PSRR+ = 87dB etc. I don't know how to plot CMRR. Could someone explain the setup. Thanks.
Jan 10, 2005 #2 L leebluer Member level 4 Joined Apr 20, 2004 Messages 76 Helped 5 Reputation 10 Reaction score 3 Trophy points 1,288 Location China Activity points 742 Re: about CMRR of an op-amp Pls refer the book of CMOS Analog Circuit Design by Allen. with an amplifier with unity-gain form, you could get the CMRR.
Re: about CMRR of an op-amp Pls refer the book of CMOS Analog Circuit Design by Allen. with an amplifier with unity-gain form, you could get the CMRR.
Jan 10, 2005 #3 V v_naren Guest Re: about CMRR of an op-amp This will help I think If I have helped you..could you please click the helped me button and help me. thank you :-D
Re: about CMRR of an op-amp This will help I think If I have helped you..could you please click the helped me button and help me. thank you :-D
Jan 11, 2005 #4 Y yilmazerc Newbie level 5 Joined Jan 11, 2005 Messages 10 Helped 1 Reputation 2 Reaction score 0 Trophy points 1,281 Activity points 79 Re: about CMRR of an op-amp short the inputs and apply an ac source at 1V then see the output. it gives the common mode gain.Avcm CMRR=Av/Avcm
Re: about CMRR of an op-amp short the inputs and apply an ac source at 1V then see the output. it gives the common mode gain.Avcm CMRR=Av/Avcm
Jan 11, 2005 #5 E Enrique15 Member level 3 Joined Jan 8, 2005 Messages 56 Helped 1 Reputation 2 Reaction score 0 Trophy points 1,286 Location Panama Activity points 1,427 Re: about CMRR of an op-amp I don't know how to plot CMRR Click to expand... When you say "plot", you refer to plot the signal with a simulation program (like PSpice).... Or just want parameters to "calculate" the Avcm by yourself, so to do the formula: CMRR=Avd/Avcm Regards.
Re: about CMRR of an op-amp I don't know how to plot CMRR Click to expand... When you say "plot", you refer to plot the signal with a simulation program (like PSpice).... Or just want parameters to "calculate" the Avcm by yourself, so to do the formula: CMRR=Avd/Avcm Regards.
Jan 17, 2005 #6 R radigital Junior Member level 2 Joined Dec 28, 2004 Messages 23 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,283 Activity points 274 Re: about CMRR of an op-amp Read Design of Analog Integrated Circuits by Paul R Gray and Rober Mayor. Analog IC Design by Allan and Holberg also helps.
Re: about CMRR of an op-amp Read Design of Analog Integrated Circuits by Paul R Gray and Rober Mayor. Analog IC Design by Allan and Holberg also helps.
Jan 17, 2005 #7 G gqxfw Junior Member level 3 Joined Jul 3, 2002 Messages 30 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,288 Activity points 126 Re: about CMRR of an op-amp Acmrr=Avd/Acm All books on integrated circuit has talked about it. Please refer to one text.
Re: about CMRR of an op-amp Acmrr=Avd/Acm All books on integrated circuit has talked about it. Please refer to one text.
Jan 29, 2005 #8 richloo Full Member level 1 Joined Aug 24, 2004 Messages 95 Helped 9 Reputation 18 Reaction score 4 Trophy points 1,288 Location Isolated Island Activity points 748 about CMRR of an op-amp Can anyone tell me how to get CMRR, PSRR from xf analysis in cadence? thanks in advance!
about CMRR of an op-amp Can anyone tell me how to get CMRR, PSRR from xf analysis in cadence? thanks in advance!
Feb 2, 2005 #9 A avinash Full Member level 3 Joined Jul 24, 2004 Messages 160 Helped 10 Reputation 20 Reaction score 3 Trophy points 1,298 Activity points 1,527 Re: about CMRR of an op-amp just short the inputs and perform ac analysis.you get common mode gai at the output.subtract this common mode gain with Ad.you get cmrr.don't forget you short the input with proper input offset voltage apllied at -ve input
Re: about CMRR of an op-amp just short the inputs and perform ac analysis.you get common mode gai at the output.subtract this common mode gain with Ad.you get cmrr.don't forget you short the input with proper input offset voltage apllied at -ve input
Feb 3, 2005 #10 C cliffj Member level 3 Joined Mar 22, 2004 Messages 55 Helped 4 Reputation 8 Reaction score 3 Trophy points 1,288 Activity points 533 Re: about CMRR of an op-amp Construct your opamp as a unity gain buffer and you can easily get the CMRR simulation result. Check P. Allen's book
Re: about CMRR of an op-amp Construct your opamp as a unity gain buffer and you can easily get the CMRR simulation result. Check P. Allen's book
Feb 8, 2005 #11 S shelkerahul Member level 4 Joined Feb 8, 2005 Messages 79 Helped 10 Reputation 20 Reaction score 7 Trophy points 1,288 Location Bangalore Activity points 581 Re: about CMRR of an op-amp Hi, You just connect both the terminals of OP-AMP and connect the AC voltage source of 1Vp-p, do the AC analysis. It will give you the CMRR. Rahul
Re: about CMRR of an op-amp Hi, You just connect both the terminals of OP-AMP and connect the AC voltage source of 1Vp-p, do the AC analysis. It will give you the CMRR. Rahul
Feb 12, 2005 #12 X xiang Newbie level 3 Joined Feb 8, 2005 Messages 3 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 26 Re: about CMRR of an op-amp Check the book: Op Amps for everyone