An off-chip IDDq current measurement unit for telecommunication ASICs

This paper describes the realisation, the operation and the test results of an off-chip IDDq current measurement unit, called OCIMU. The monitor is original in that, if was designed in response to a demand for a circuit that is dedicated to measure the IDDq of telecommunication ASICs. It can be incorporated into a standard ATE during normal engineering and production testing. The monitor is capable of performing at relative high speed (>10 kHz) accurate quiescent current measurements in the 1 μA-1 mA range. The OCIMU circuit does not affect the Device Under Test supply voltage. It provides a stable power supply in the 3 to 7 volt range. Furthermore, the monitor is capable of driving high capacitive loads (>2μF) without speed degradation and to deliver high transient switching currents (up to 10 A). The operation of the OCIMU circuit is based upon the use of the stabilised voltage drop (SVD) principle