The MAX3964 limiting amplifier, with 2mV P-P input sensitivity and PECL data outputs, is ideal for low-cost ATM, FDDI, and Fast Ethernet fiber optic applications. The MAX3964 features an integrated power detector that senses the input-signal power. It provides a received-signal-strength indicator (RSSI), which is an analog indication of the power level and complementary PECL loss-ofsignal (LOS) outputs, which indicate when the power level drops below a programmable threshold. The threshold can be adjusted to detect signal amplitudes as low as 2.7mVP-P. An optional squelch function disables switching of the data outputs by holding them at a known state during an LOS condition. The MAX3965 provides the same functionality, but offers TTL-compatible LOS outputs. The MAX3968 provides the same functionality as the MAX3964, but has data-output edge speed suitable for ESCON and 266Mbps fibre channel applications.