Integrated circuit with configurable on-die termination

摘要

Described are integrated-circuit die with differential receivers, the inputs of which are coupled to external signal pads. Termination legs coupled to the signal pads support multiple termination topologies. These termination legs can support adjustable impedances, capacitances, or both, which may be controlled using an integrated memory.

主权项

1. A communication system comprising:
a first integrated circuit (IC) having:
a transmitter to transmit a differential signal; andfirst differential pads to convey the differential signal from the first IC; a differential channel coupled to the first differential pads to communicate the differential signal; and a second IC having:
second differential pads coupled to the differential channel to receive the differential signal, the second differential pads including a first pad and a second pad; andon-die termination circuitry that includes:
a common node;a first termination leg extending between the common node and the first pad, the first termination leg including a first termination impedance;a second termination leg extending between the common node and the second pad, the second termination leg including a second termination impedance; anda third termination leg extending between the common node and a reference-voltage node, the third termination leg including a switch to selectively couple the common node to the reference-voltage node.