Choice and Number of Caps for min noise - RF Cafe Forums

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darcyrandall2004
Post subject: Choice and Number of Caps for min noise Posted: Mon Aug 04, 2008 7:48 am

Colonel

Joined: Tue Feb 27, 2007 6:16 am
Posts: 46
Hello,

I wish to be able to determine the minimum number of capacitors required and typical values to be used on the input and output of a voltage regulator, to achieve a desired noise ripple (and a minimum amount of soldering).

Can anyone recommend a well explained decent text?

Thankyou

_________________
Regards, Darcy Randall, Perth, Western Australia

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RFDave
Post subject: Linear regulatorsPosted: Mon Aug 04, 2008 9:48 pm

Captain

Joined: Sat Apr 22, 2006 11:14 pm
Posts: 10
Have you looked through App notes at Linear technologies and Analog Devices? I'd start from there.

Dave

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IR
Post subject: Posted: Thu Aug 07, 2008 4:27 pm

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hello Darcy,

For most of the regulators a single capacitor is required at the input and 1-2 are required at the output. The capacitors should have the right ESR (Not too high - ripple, but also not too low - for stability), the right technology (Usually X7R, X5R) for temperature stability. In the device's data sheet, there are usually recommendations for the capacitance value and the required ESR.

Hope this helps.

Posted 11/12/2012