Series-gated emitter-coupled logic circuit providing closely spaced output voltages

摘要

An emitter-coupled logic circuit provides differential outputs which are delivered to pairs of transistors in emitter-coupled logic (ECL) switches. The differential outputs allow additional ECL switches to be connected between a positive and negative supply voltage. A unique current source for the ECL switches includes diodes and/or transistors connected in parallel with the ECL switches such that the supply current is relatively independent of fluctuations in the supply voltage and yet the voltage drop across the current source is minimized.