Power supply current monitoring techniques for testing PLLs

The effectiveness of current testing for digital IC's has led researchers to explore the possibility of extending this concept to testing analog blocks of mixed-signal ICs. Unfortunately, test techniques developed for commonly-studied analog blocks such as op-amps and filters do not apply to non-linear blocks such as phase-locked loops. This paper focuses on investigating the effectiveness of using an operating power supply current monitoring technique to detect potential faults in a phase-locked loop (PLL) circuit.