Boost regulator: Unexpected output voltage
It turns out that I was using a partially correct application circuit. According to this link, it turns out that when using the fixed output version of this chip, I need to short the feedback (pin 2) to the output of the Schottky diode, and I'm all set.


  The schematic is simple, easy to build and cost effective, producing
  12V from a 5V unregulated supply with a maximum output current of
  800mA. Pin numbers shown are for the TO-220 package (LM2577T-ADJ).
  
  The design uses the adjustable version of LM2577, but the 12V
  fixed-voltage version (LM2577T-12) will also work if you remove R1 and
  R2 and connect the feedback pin directly to the regulator's output.
  The UC2577 - a pin to pin compatible replacement available from Texas
  Instruments can also be used.