A sampling oscilloscope macro toward feedback physical design methodology

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 methodology. 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.