I need to add a 15V dc reference voltage to board. I'm going to compare it to some other signals through an ADC for calibration purposes. 20mA would be plenty.

I only have 12VDC on the rail. I can get a small 2577 boost module on Ebay for less than 3 bucks that will do the step-up, but it takes up a lot of space and is about 15x more power than I need. Seems like overkill.

Is there a small, low component count way for me to do the step up with an IC?
Accuracy needs to be about 0.5%.

 

You could make a free running boost with a 555, a 2N3904 and an inductor with a zener clamp on the output.

I made one that boosts 1.5V to 13V, use the same idea.

 

I like this idea. Only issue is that the most stable rail I have is about 10VDC, so I would have to adjust at least R1 and beef up the zener.

While looking up the parts on Digikey, I found the LMV431. Looks like this with a couple of resistors might be all that I need. All for less than a buck.

 

The LMV431 won't work, does not boost input voltage.

Back to bounthunter's tip.

 

There is a simple 2-transistor circuit here;
http://www.romanblack.com/smps/conv.htm

that will give 15v output from a 12v or 5v input.

 

Some pre-fab modules:

 

Or if you like capacitors.

If you were just funning about the .5% you can replace the 431 with a zener.