Choice and Number of Caps for min noise - RF Cafe Forums
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Post subject: Choice and Number of Caps for min noise Posted: Mon Aug 04, 2008 7:48 am
Joined: Tue Feb 27, 2007 6:16 am
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?
Regards, Darcy Randall, Perth, Western Australia
Post subject: Linear regulatorsPosted: Mon Aug 04, 2008 9:48 pm
Joined: Sat Apr 22, 2006 11:14 pm
Have you looked through App notes at Linear technologies and Analog Devices? I'd start from there.
Post subject: Posted: Thu Aug 07, 2008 4:27 pm
Joined: Mon Jun 27, 2005 2:02 pm
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.