Re: [SI-LIST] : Power Supply Noise Filters

Michael T Zhang (
Fri, 27 Mar 98 13:38:00 PST

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You basically have two choices: linear regulator or switching regulator.
Linear regulator would have less than 50% efficiency based on your
input/output voltage ratio. So power consumption on the regulator might
be an issue if the current is high. However, it would filter out much of
the input noise (high audiosusceptibility). Switching regulator on the
other hand has good efficiency and high audiosusceptibility, but
introduces noise at the output due to its own switching. If noise is
critical, you can use multiple-stage low-pass filters. Common practices
are using linear for low-power applications; and switchers for
high-power ones.

-Michael Zhang

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Subject: [SI-LIST] : Power Supply Noise Filters
Author: owner-si-list@silab.Eng.Sun.COM at SMTPGATE
Date: 3/27/98 11:21 AM

Hello everybody,

I have a regulator on my board that requires a +5 V input which in
turn provides +2.5 V to my circuitry. Would you guys have any recommendation
on any power supply noise filters that I can use to minimize any noise
generated by my +5V external power supply. I would appreciate any
inputs on what kind of power supply I should use.


Khalid Ansari LSI Logic Corporation
Applications Engineering 1551 McCarthy Blvd
Tel: 408.954.4965 MS G-750
Fax: 408.433.2840 Milpitas CA-95035

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Subject: [SI-LIST] : Power Supply Noise Filters
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