Threshold-programmable Loss-of-signal Detection Circuit with Temperature Compensation

Abstract

It is a challenge to implement a loss-of-signal (LOS) circuit with a wide threshold voltage range that is insensitive to temperature. This paper presents a new wide-range threshold-programmable LOS detector with full temperature compensation for application in 25Gb/s high-speed optical communication receivers. The wide-range programmable threshold voltage of the LOS detector is achieved by adjusting the threshold voltage of the peak detector and the gain of the variable gain amplifier (VGA). The detection accuracy is obviously improved by using offset self-cancellation technology for the comparator (COMP) and temperature compensation technology for the VGA and the peak detector. The LOS detector has been fabricated in 0.18 um BICMOS process and occupies 0.03 mm². The programmable threshold voltage range is 11∼130 mV for the 25Gb/s non-return-to-zero code, the hysteresis is 2 dB, and the max detection error is 4 mV. The LOS detector consumes 2.18 mW from 1.8 V supply voltage.