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raja.cedt Senior Fellow Offline Posts: 1516 Germany	integrated noise VS psd Feb 09^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.
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ywguo Community Fellow Offline Posts: 943 Shanghai, PRC	Re: integrated noise VS psd Reply #1 - 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
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raja.cedt

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Re: integrated noise VS psd
Reply #2 - 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.

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RobG

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Bozeman, MT

Re: integrated noise VS psd
Reply #3 - Feb 9^th, 2012, 5:40am

raja.cedt wrote 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.

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.

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