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Design >> Analog Design >> how to simulate PSR in an differential amplifier
https://designers-guide.org/forum/YaBB.pl?num=1244767707

Message started by uu@uk on Jun 11^th, 2009, 5:48pm

Title: how to simulate PSR in an differential amplifier
Post by uu@uk on Jun 11^th, 2009, 5:48pm

Hi,

actually I am going to simualte how an differential amplifer reject the power supply induced jitter at the output using Spectre. One suggestion is to superimpose a sinusoid signal at the power supply and run transient simulation to check the crossing deviation at the output. However, it is time penalty.

Anyone has other methods by using PSS or PXF? Thanks.

Title: Re: how to simulate PSR in an differential amplifier
Post by raja.cedt on Jun 11^th, 2009, 11:18pm

hi,
you can search there are many ports in here for PSRR. And there is some test bench in http://www.designers-guide.com/Analysis .But try to apply pulse with rise time at the frequency of interest.
Are you using diff amp for any oscillator?
thanks,
Rajasekhar.

Title: Re: how to simulate PSR in an differential amplifier
Post by uu@uk on Jun 12^th, 2009, 10:43pm

Hi Raja,

Thanks for your information. I found some useful discussions here. Actually the differential amplifier is not for any kind of osc. It is for a buffer chain.

Title: Re: how to simulate PSR in an differential amplifier
Post by raja.cedt on Jun 13^th, 2009, 7:04am

hi
if you are not using diffamp for oscillator purpose then why your interested in o/p jitter?

Thanks,
rajasekhar.

Title: Re: how to simulate PSR in an differential amplifier
Post by uu@uk on Jun 13^th, 2009, 1:59pm

Hi Raja,

Sorry. Maybe I misled. It is an amplifier in the PLL based freqency synth. That is why I care about o/p jitter.

Thanks

Title: Re: how to simulate PSR in an differential amplifier
Post by raja.cedt on Jun 13^th, 2009, 9:08pm

hi uu@uk,
where you are using this amplifier? and how did you find jitter then (normally jitter means peak to peak variation in the time period).

Thanks,
Rajasekhar.

Title: Re: how to simulate PSR in an differential amplifier
Post by uu@uk on Jun 14^th, 2009, 11:45pm

Hi Raja,

I just insert the differentail amplifier before output buffer. Using the differential one but not CMOS inverter because it suppress lot of power supply noise and substrate noise induced jitter.

Do you mean how to simulate power supply noise induced jitter or device noise induced jitter? for the device noise induced jitter, you just can easily using "Pnoise" to get the jitter results. But for power supply noise induced jitter. it is kind of confused to me. I tried using transient simulation, but it is time penalty. Now I wanna convince myself to use PXF to achieve the jitter at the output. I am still working on it. If you are also still interested in this problem or you have any good suggestion. welcome to send me email by luvckt@live.com

Title: Re: how to simulate PSR in an differential amplifier
Post by Frank Wiedmann on Jun 15^th, 2009, 1:31am

Take a look at http://www.designers-guide.org/Forum/YaBB.pl?num=1224609785/13#13 and read (at least) reply #13 to #18 (please note that the thread has three pages).