A high-speed low-power JFET pull-down ECL circuit

A high-speed low-power ECL (emitter coupled logic) circuit with an active pull-down output stage that utilizes a ″free″ JFET (junction FET) available in any npn bipolar technology is described. The JFET pull-down output stage operates as a push-pull follower stage and enhances both the speed and load driving capability. Simulation results based on an 0.8-μm double-poly self-aligned bipolar technology indicate that the circuit with a typical loading at a power consumption of 1 mW per gate offers 24% improvement in the pull-down delay and 53% improvement in the load driving capability compared with the conventional ECL circuit.