Emitter-coupled logic uses bipolar junction transistors where the emitters are connected together and current is steered between paths rather than turned completely on or off. Because the transistors never saturate, ECL is extremely fast, avoiding the storage-time delays of standard TTL logic. It historically dominated supercomputers and high-frequency telecom circuits, though it consumes heavy static power and requires negative supply voltages.
We had to use ECL for the clock distribution network to keep the jitter under control.
ECL inputs are notoriously sensitive to impedance mismatches, so proper termination is mandatory to avoid reflections.
Also heard as
- emitter-coupled logic
Related terms
TTL
Transistor-transistor logic is a classic digital circuit design family built from bipolar junction transistors.
CMOS
Complementary metal-oxide-semiconductor is the dominant fabrication technology for integrated circuits.
Logic level
A specific voltage range that represents a distinct binary state in a digital circuit.