Abstract: A novel, programmable assert threshold loss-of-signal detector is designed and realized for intelligent optical modules with 0.6μm 2P2M CMOS technology.The detector includes a pseudo-log received-signal-strength-indicator (RSSI) which uses a limiting amplifier in the data path of the optical receiver, a hysteresis comparator, a bandgap generator, an op-amp, and two off-chip resistors.With a 155Mbps input pseudo random sequence, this pseudo-log RSSI achieves a 60dB dynamic indicating range with a logarithmic accuracy of less than ±2dB, and a programmable assert threshold of 1~700mV with a 4dB stable hysteresis.It consumes 60mW from a single 5V supply.The chip area, including pads, is 1.1mm2.

Key words: loss-of-signal, pseudo-logarithmic, received-signal-strength-indicator