A level shifting circuit which can be implemented as part of a bipolar ECL integrated circuit, provides reliable switching and level shifted output suitable for driving a low voltage CMOS integrated circuit. The circuit includes a level shifting circuit which is connected to trigger a high gain positive feedback bootstrap circuit to reliably ensure switching even under poor signal conditions. An output taken from one of the switched pair is allowed to go to V.sub.CC, 0 volts, or is clamped by a clamping circuit to -3.3 volts, representing the two output states suitable for driving inverted rail CMOS circuitry.