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Design >> Analog Design >> integrated noise VS psd
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Message started by raja.cedt on Feb 9^th, 2012, 12:42am

Title: integrated noise VS psd
Post by raja.cedt on Feb 9^th, 2012, 12:42am

hello,
can any one tell me for an band gap reference what kind noise metrics we have to consider, means integrated noise or PSD?

why i am asking this question is some one told me for an LDO we have to consider PSD at some offset frequency.

Thanks for your time.

Thanks,
Raj.

Title: Re: integrated noise VS psd
Post by ywguo on Feb 9^th, 2012, 1:00am

Hi Raj,

I think that depends on application. For example, an RF transciever needs low-noise LDO. Since most wireless communication standards have spectrum spec, it is reasonable to have good PSD at some offset frequency. What is your application? What does system or RF engineers expect?

Best Regards,
Yawei

Title: Re: integrated noise VS psd
Post by raja.cedt on Feb 9^th, 2012, 3:57am

hello,
yes, so if an ldo is driving vco then i have convinced with your answer. Now let us say i am doing a band gap for my chip which is generating currents to all bias circuitry and this is wireline communication chip (so here jitter is more imp than spot noise ), so may be i have to concentrate on integrated noise rather than spot. Correct me if am wrong.

Thanks,
Raj.

Title: Re: integrated noise VS psd
Post by RobG on Feb 9^th, 2012, 5:40am

raja.cedt wrote on Feb 9^th, 2012, 3:57am:

It really depends on your application like Yawei says - communication circuits usually are most interested in noise at a particular frequency (or a small range of frequencies) since everything else is heavily filtered. Applications where the reference is sampled worry about the integrated noise, but also the spectrum since the noise gets aliased.