Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Question on PSRR Measurement

Status
Not open for further replies.

suria3

Full Member level 5
Joined
Mar 5, 2004
Messages
304
Helped
17
Reputation
34
Reaction score
5
Trophy points
1,298
Activity points
3,042
.extract ac label=

Hi guys,

I have a question here on exact method of PSRR measurement. When i referred to Philip Allen book on the method of PSRR measurement of a opamp, it is stated that the opamp is put in the unity configuration, so the closed loop gain is 1. The PSRR definition in general is given as PSRR=[Vout/Vin]/[Vout/Vsupply]. So since the opamp gain is 1, then the PSRR=Vsupply/Vout=PSR. My question here is, when i measured the opamp in the open loop configuration and I measured the PSRR of the opamp at 10kHz with the same concept as PSRR=[Vout/Vin]/[Vout/Vsupply], i'm not getting the same result, which means the transient suppresion from supply to output not same as measurent from AC simulation. Why?? It only gives same result of AC and transient when the opamp in the unity configuration. Does it mean that the opamp gain not helping in PSRR? Please explain about this confusion.

Suria.
 

eric.hanyq

Newbie level 3
Joined
Sep 11, 2007
Messages
3
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,293
Actually,Vout=Add/(1+Av) Vdd~Add/Av Vdd =Vdd/PSRR.Av is the large the better!!
If it was as you said,maybe your setting is wrong or coincidental .....
 

gafsos

Full Member level 4
Joined
Feb 1, 2006
Messages
190
Helped
24
Reputation
48
Reaction score
11
Trophy points
1,298
Location
North Africa
Activity points
2,450
.EXTRACT AC LABEL = PSRR_min FILE=PSRR.aex MAX(Vdb(VBG))
.EXTRACT AC LABEL = PSRR_dc FILE=PSRR.aex yval(Vdb(VBG),1)
.EXTRACT AC LABEL = PSRR_min_freq FILE=PSRR.aex XMAX(Vdb(VBG))
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top