Low-Power, 622Mbps Limiting Amplifiers with Chatter-Free Power Detect for LANs

Active: In Production.

The MAX3761/MAX3762 limiting amplifiers, with 4mV sensitivity and PECL data outputs, are optimized for operation in low-cost, 622Mbps, LAN/ATM LAN fiber optics applications.

An integrated power detector senses the input signal's amplitude. A received-signal-strength indicator (RSSI) gives an analog indication of the power level, while the complementary loss-of-signal (LOS) outputs indicate if the input power level exceeds the programmed threshold level. The LOS threshold can be adjusted to detect signal amplitudes between 3mV_P-P and 100mV_P-P, providing a 15dB LOS adjustment in fiber optic receivers. The LOS outputs have 3.5dB of hysteresis, which prevents chatter when input signal levels are small. The MAX3761's LOS outputs are compatible with TTL-logic levels. The MAX3762 has PECL LOS outputs.

DISABLE and LOS can be used to implement a squelch function, which turns off the data outputs when the input signal is below the programmed threshold.

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