PHASE LOCKED LOOP WITH BURN-IN MODE

摘要

A phase locked loop having a normal mode and a burn-in mode. The logic portion is coupled to a logic power supply terminal and includes a clock receiver coupled to a phase frequency detector. The analog portion has a charge pump coupled to the phase frequency detector and to an analog power supply terminal. The analog portion also has a voltage controlled oscillator coupled to the charge pump at an analog node and to the analog power supply terminal. The phase locked loop has a node control circuit that is coupled to the analog node during the burn-in mode that controls a voltage at the analog node sufficiently below a voltage at the analog power supply terminal to avoid over-stressing the charge pump and the voltage controlled oscillator during the burn-in mode.