> At 11:49 AM 5/16/2006 -0700, you wrote:
>>We currently have several products running off an unregulated external
>>12VDC power supply (wall wart). Inside our product, we run through a
>>1N4001 for reverse polarity protection, then 1n LM7805 to regulate to +5V
>>(to run the PIC!). Upcoming California Energy Commission regulations
>>outlaw these external power supplies (due to lack of efficiency and
>>standby power). We could replace these with 12V regulated switchers, but
>>that is pretty inefficient. What I'd like to do is replace them with
>>external 5V switchers, yet continue to allow the use of the old power
>>supplies. It would be great if there were an LDO equivalent of the TO-200
>>LM7805 with reverse polarity protection (so I could get rid of the diode
>>and its drop). Anyone aware of a drop-in replacement?
>>
>>THANKS!
>>
>>Harold
>
> LM2940C mostly meets your stated requirements. Of course you'll need a bit
> more than 5V in to get 5V regulated out! If you're just using the
> regulator
> as a low-drop diode, it's a bit expensive, but might be acceptable if it
> means you don't have to do another PCB for a low-volume product.
>
> Note also that they are not kidding on the minimum output capacitance
> required for stability (22uF in this case), so it may not be 'drop in'
> in your particular case. The ESR must also not be too high or too low,
> or again it may oscillate (don't use a ceramic 22uF cap, for example).
>
>>Best regards,
>
> Spehro Pefhany --"it's the network..."            "The Journey is the
> reward"
> speff@interlog.com             Info for manufacturers:

Looks good! Thanks!

Harold

-- 
FCC Rules Updated Daily at http://www.hallikainen.com - Advertising
opportunities available!
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist