The present invention is a sense amplifier circuit for use with programmable logic devices, that provides improved switching time by actively limiting the voltage swing on the bit line which it is sensing, rather than passively sensing the voltage, and that employs feedback circuits to further improve switching time. Voltage reference control circuitry, comprising variable current limiters controlled by the potential of a supply of reference potential, can be added to improve noise immunity. The circuitry of the supply of reference potential is designed so that its sensitivity to fabrication variations is substantially similar to that of the sense amplifier and so that it adjusts the reference potential accordingly.