Adaptive driver with automatic sense and calibration in CMOS 40LP

摘要

Dynamically calibrated driver block is presented which automatically adapts its termination resistance to the channel's impedance. The driver senses the channel and calibrates to its characteristic impedance anywhere between 30 – 120 ohms. This circuit functions successfully for a minimum propagation delay of 500 ps on the channel. Results on the STM CMOS 40LP process confirm the driver's impedance match to that of the line with an accuracy of +/− 8% with +/−3σ variation in the process, +/− 10% voltage spread at 2.5V and temperature variation range of − 40 to 125 degrees centigrade.