NVIDIA Corporation
SELF-CLOCKING SAMPLER WITH REDUCED METASTABILITY

Abstract:

A circuit, method, and system are disclosed for sampling a signal. The system includes a sampler circuit configured to sample input signals when a clock signal is at a first voltage level to produce sampled signals, a detection circuit that is coupled to the sampler circuit, and a feedback circuit that receives an output signal and generates the clock signal. The detection circuit pre-charges the sampled signals when the clock signal is at a second voltage level and, using threshold adjusted inverters, detects voltage levels of each sampled signal to produce detected voltage levels, where a threshold voltage of the threshold adjusted inverters is entirely outside of a transition voltage range of the sampler circuit. In response to one of the detected voltage levels transitioning from the second level to the first level, the detection circuit transitions the output signal from the first voltage level to the second voltage level.