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Simulators >> Circuit Simulators >> Slew Rate Test for OP-AMP
https://designers-guide.org/forum/YaBB.pl?num=1445971912

Message started by Ramakrishna RSSM on Oct 27^th, 2015, 11:51am

Title: Slew Rate Test for OP-AMP
Post by Ramakrishna RSSM on Oct 27^th, 2015, 11:51am

Hey All,

I have setup my Op-Amp under Slew Rate Test....

Input 1m Pulse-------->slewRate is 45K

Input 1u Pulse-------->slewRate is 45M

I'm unable to interpret What is the SLEW RATE of my design.....?

At what value of Input Pulse Slew Rate should be measured.....?

Follow the attachments for my concern......

Thanks in advance.......

Title: Re: Slew Rate Test for OP-AMP
Post by Ramakrishna RSSM on Oct 27^th, 2015, 11:53am

Sorry,

forgot to attach u_scale file.....

Thanks in advance.....

Title: Re: Slew Rate Test for OP-AMP
Post by saqibshah on Oct 28^th, 2015, 5:16am

Please mention the units correctly - are you referring to uV or us?

Also please attach the output node waveforms - you need to make sure that opamp is actually slewing properly so as to say. A 1us input pulse might actually not be giving your opamp enough time to properly slew. Also, what is the value in volts of the input step?

Finally, what is the rise time/ fall time of the pulse?

Title: Re: Slew Rate Test for OP-AMP
Post by Ramakrishna RSSM on Oct 28^th, 2015, 11:41pm

Thanks for your reply saqibshah.......

Input 1 mS pulse with V1=1.5 V and V2=1 V ----> slewRate = 45K V/S
Input 1 uS pulse with V1=1.5 V and V2=1 V ----> slewRate = 45M V/S

The Diff-Amp is designed in gpdk180 with VDD=1.8 V.

Follow the attachments for the waveforms.....

I haven't specified any rise/fall time So rise/fall time would be 1% of period i.e: for
1 mSec pulse rise/fall time is 10 uSec
1 uSec pulse rise/fall time is 10 nSec

Could you please explain how to identify PROPER SLEWING......?

Title: Re: Slew Rate Test for OP-AMP
Post by AnilReddy on Nov 6^th, 2015, 5:48am

show your amp structure, how much are you expecting based on calculations, where is input where is output.