Patent ID: 7439789

Claim:
An integrated-circuit die comprising: a. a plurality of bonding pads to couple to respective ones of a plurality of communication channels and, for each bonding pad, i. a communication circuit coupled to the bonding pad, wherein the communication circuit is a transmitter or a receiver to transmit or receive a signal over the corresponding communication channel; and ii. a compensated resistor coupled between a termination voltage node and the bonding pad to exhibit a termination resistance, the compensated resistor including a select port to receive a digital select signal, an analog calibration port to receive an analog calibration signal, and a plurality of switches, wherein an analog compensation circuit is coupled to the control terminals via the switches and the switches comprise level shifters to adjust a level of the analog calibration signal; and b. the analog compensation circuit is coupled to each analog calibration port to deliver the analog calibration signal, wherein the analog calibration signal tunes the termination resistances of the compensated resistors to match characteristics of the corresponding communication channels.