Stimulus generation for built-in self-test of charge-pump phase-locked loops

This paper addresses the issue of the stimulation of charge-pump phase-locked loops for built-in self-test applications. It is shown that three nodes of the PLL qualify for test signal injection. The hardware and methodology for each are discussed. In particular, a comprehensive explanation of the use of delta-sigma modulation in the time domain is provided. Furthermore, implementation issues of analog tests with signal generation based on coarse quantization are discussed. The effects of the quantization noise arising from delta-sigma modulation on the dynamic range of phase-locked loop nodes is evaluated. Original experimental results validate one of the method which was not verified previously. In conclusion, the strengths and weakness of each of the three methods for phase-locked loop stimulation are highlighted.