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

Khalid Ansari (kansari@lsil.com)
Mon, 30 Mar 1998 14:56:23 -0800

Hi Michael,

Thanks for your response on the Power supply email that I had sent
earlier. Actually, I didn't make myself very clear, I apologize. I am
looking for a noise filter that I can layout on my board to dissipate
any noise generated by an external +5V raw, PC, power supply coming into
a regulator that I am using to generate a +2.5V output. Your response
regarding use of regulators in this case is helpful, but I will really
appreciate if you could suggest a noise filter I could use.

Thanks
Khalid

Michael T Zhang wrote:
>
> Text item:
>
> 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

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

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