Abstract: An optical receiver has a voltage supply, a first node, and a second node. A first input of a differential amplifier is coupled to the first node and a second input of the differential amplifier is coupled to the second node. A photodetector is coupled between the voltage supply and the first node, which produces a photodetector capacitance. A programmable variable capacitor having a capacitance selectively matched to the photodetector capacitance is coupled between the voltage supply and the second node.

Abstract: A circuit that protects against electrostatic discharge and electrical over stress is provided. The circuit includes a first transistor including a substrate. An internal predetermined voltage source biases the substrate of the first transistor. The internal predetermined voltage source is greater than or equal to a source voltage provided to a source of the first transistor and isolates a substrate voltage of the first transistor from a supply voltage of the circuit. A first resistor is coupled to a gate of the first transistor and ground. The circuit also includes a zener diode coupled between ground and the supply voltage of the circuit. The zener diode shorts to ground if the supply voltage of the circuit exceeds the breakdown voltage of the zener diode.

Abstract: In a method for operating a plurality of optical sensors, each of the optical sensors is sequentially coupled to a shared input of a receiver. When electrically coupling a given one of the optical sensors to the shared input, at least one other of the optical sensors is shunted to ground. Apparatus that may be used to implement the method is provided with a plurality of optical sensors, and a receiver having a shared input. Each of a first plurality of switches couples one of the optical sensors to the shared input of the receiver. Each of a second plurality of switches shunts one of the optical sensors to ground.

Abstract: An optical receiver includes a photodetector coupled to a gain section having a variable gain stage. The gain stage provides an output voltage signal. A digital automatic gain control circuit is coupled to the output voltage signal and provides a digital output value to at least the variable gain stage. The gain of the variable gain stage is set according to the digital output value.

Abstract: A circuit has a voltage source, a node, a photodiode electrically coupled between the voltage source and the node, a voltage reference, a resistor electrically coupled between the node and the voltage reference, and a voltage clamp electrically connected to the node.