Tutorial: On Chip Voltage and Timing Diagnostic Circuits

This tutorial introduces a set of practical and powerful techniques and circuits to observe and characterize on-die circuitry. Measuring voltage and timing information on the chip itself alleviates the bandwidth and noise limitations associated with bringing signals off-chip to be measured. Specific applications of these techniques include measurement and characterization of power supply noise, power delivery impedance, clock skew, phase interpolator linearity, I/O eye margins, waveform capture, RX voltage noise and hysteresis, and RX clock-data jitter. Because the measurements are fully integrated, the rest of the system can be automatically adapted based on these metrics in a stand-alone manner. Best of all, many of these techniques leverage existing circuitry and are highly digital.