An integrated multi-channel optical sensor receiver with considerations of channel-isolation for digital output

In this paper, a low power, high density and fully integrated CMOS receiver front-end with digital output for optical signal processing systems is presented. The circuit is composed of transimpedance amplifier for weak optical current detection, limiting amplifier for both linear and limiting amplifications, control circuits and the digital output interface. The front-end is powered by a single 3.3V power supply with the power supply current of 12mA. Measured with a photodiode, a sensitivity of 0.7μA was achieved. The channel isolation between 8 channels is considered during the period of circuit design, layout floor plan and measurement carefully. The digital output signal is compatible with TTL/CMOS logic interface which can reduce the size of system dramatically and is easy to use. The optical sensor receiver was fabricated with a commercial mixed-signal CMOS process with feature size of 0.6μm, taking silicon area of 1.91mm×1.01mm including bonding pads for 8 channels.