I have a EMCO AG15P-5 DC-DC converter (datasheet) that takes 0-5V in and outputs up to 1.5kV (proportional to input voltage). I need to operate the converter at 500V output. I've done testing with a precision voltage source and determined that an input voltage of 1.14V gives 500V output. Under full load, the converter uses ~20mA, and this value would be constant in my application. Given the converter's proportional output, the input voltage needs to remain as stable as possible. Moreover, the precision of the voltage source would ideally keep it steady in the 10s of millivolts. So now I need to figure out how to provide stable 1.14V @ 20mA to power this sucker.
My first thought was to use an LM317 with a divider network. I think this wont work considering the 1.25V Vref of the LM317. I've searched digikey for regulators and found this regulator, but am not sure if buck regulators are the best for this, considering stability