A transistor voltage reference-and what the bandgap has to do with it
Amy Brokaw · 2002
Summary form only given, as follows. Many ICs lack stable avalanche or Zener diodes or the operating voltage to derive a reference voltage. A stable, reproducible low-voltage reference can be derived from a bipolar transistor base-emitter junction. The operating principle of such circuits is described and the significance of the bandgap voltage is explained.>