In electronics,
emitter-coupled logic (
ECL) is a high-speed
integrated circuit bipolar transistor
logic family. ECL uses an overdriven BJT differential amplifier with single-ended input and limited emitter current to avoid the saturated (fully on) region of operation and its slow turn-off behavior. As the current is steered between two legs of an emitter-coupled pair, ECL is sometimes called
current-steering logic (CSL),
current-mode logic (CML) or
current-switch emitter-follower (CSEF) logic.