Abstract: A radiation hardened circuit for a bit line driver in a ROM or PROM wherein the discharge of the bit line capacitance is enhanced by shorting the current limiting resistor momentarily at the initiation of the discharge cycle and by allowing the bit line charging voltage to go to a value only slightly less than the power supply voltage without sacrificing speed and noise immunity. The result is decreased delay time during the discharge transition without loss in noise immunity.

Abstract: An integrated circuit is disclosed which includes a charge pump adapted for biasing the substrate of a monolithic integrated circuit containing bipolar transistors. An oscillator operating under the control of a control input provides pulsed output signals for driving a diode-capacitor voltage multiplier network which generates a substrate bias voltage. A feedback network including a zener diode senses the substrate voltage, and switching action of the zener diode operates to selectively enable and disable the oscillator for regulating the substrate bias voltage.