A high speed dynamic power supply current sensor

An on-chip wideband CMOS transient supply current sensor is presented. The sensor permits on-chip transient supply current testing (iDDT) for circuits where supply current transients associated with circuit operation are measured and evaluated. The sensor was designed and fabricated in 0.5-mum CMOS technology and was physically demonstrated at 200 MHz sensing speeds. Measured results from the sensor show it is possible to distinguish between normal and faulty logic inverter operation. Extensions to the sensor design are presented including autozero circuitry to cancel MOS transistor mismatch.