PRBS testing of analogue circuits

This paper presents a time-domain approach, for testing analogue circuits that can be implemented on a digital tester. The time-domain testing strategy proposed is based on the excitation of the analogue circuit-under-test (CUT) with a sequence of pulses, and subsequent measurement of the transient response at the output node/s. Both the transient voltage at the output node/s and the transient current (Idd) of the supply current are measured. The major advantage of the transient response is that it contains all the necessary information about the CUT. This information can then be processed in a number of ways to extract measures of various parameters. In this case the authors process the transient response data to establish whether the circuit is faulty or not (i.e. Go/No-Go). The test sequence to be applied to an analogue CUT is a pseudo-random binary sequence (PRBS). The PRBS is chosen because it can be readily generated by a digital tester, such sequences have well defined properties and can be used to extract the impulse response of the CUT if required. The autocorrelation function of a PRBS signal is triangular with a base-width equal to two clock periods, which is a very good approximation of the impulse function