Size Counts!!

Thread Starter

JDR04

Joined May 5, 2011
367
Hoping somebody can help with a small power supply circuit.

I need to step 9Vdc down to 5Vdc for a microcontroller. Space is very restricted.

Any suggestions will be appreciated. Thanks - JDR04
 

apqo1

Joined Oct 5, 2008
52
How much current? Consider:
  • Microcontroller overhead
  • Loss through pull-up/down resistors when outputs are low/high
  • Current sourced from micro's outputs
  • Other loads (sensors, motors, LEDs, etc.)

Are you working with through-hole or SMD?
 

#12

Joined Nov 30, 2010
18,224
Gotta go with, "There's nothing smaller than a TO-92 package". Even a 1/2 watt resistor and a zener have difficulties beating that.
 

ErnieM

Joined Apr 24, 2011
8,377
I did it several times with nothing more then a 2512 SMD resistor and a pair of 0805 caps, but that was cheating as the PIC has an internal regulator.

Did it again using a pair of 0201 resistors, an 0201 cap and a very time transistor pair. Fit in perhaps .15 square and it was "wafer thin."
 

THE_RB

Joined Feb 11, 2008
5,438
Gotta go with, "There's nothing smaller than a TO-92 package". Even a 1/2 watt resistor and a zener have difficulties beating that.
If the O.P. can use SMD parts, you can get a lot of 5v linear regulators in the tiny SOT-23 package.
 

THE_RB

Joined Feb 11, 2008
5,438
Yeah it would be great if people asking for help actually provided enough information. ;)

But in the context of using it "for a microcontroller" we know a lot of micro projects only use a handful of mA. SOT-23 sized 5v regulators are common enough in 100mA-200mA capacity.
 

Thread Starter

JDR04

Joined May 5, 2011
367
Thanks guys, going by some of the advice and questions asked,I need to do a bit more research so I can answer the questions raised.........
 
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