A Sampling Oscilloscope Macro Toward Feedback

A sampling oscilloscope macro which is easily embedded in an actually operating LSI in the field has been developed to enable practical use of the feedback physical design method-ology. The macro features (1) a high-speed input-isolated comparator to measure signals on GHz-digital-LSIs, (2) a voltage-range converter to widen the input range to 2 V at a 1-V supply voltage, (3) D/A converters to eliminate the use of analog I/O for the macro, (4) an on-chip power supply noise filter to eliminate the need for a dedicated power supply, and (5) an embedded clock generator to eliminate the need for a dedicated clock signal. By using the macro, the world's first measurement of an undershooting waveform caused by an on-chip inductive effect has been demonstrated