The MAX3645 limiting amplifier functions as a data quantizer and is pin compatible with the Mindspeed MC2045-2 and MC2045-2Y postamplifiers. The amplifier accepts a wide range of input voltages and provides constant-level positive emitter-coupled logic (PECL) output voltages with controlled edge speeds. The MAX3645 features an integrated power detector with complementary PECL loss-of-signal (LOS) outputs that indicate when the input power level drops below a programmable threshold. An optional squelch function holds the data outputs at static levels during a LOS condition.