US Patent 7327166 Reference buffer with improved drift

A reference voltage circuit having an open-loop buffer driven by a matching buffer included within a closed-loop, generates a stable differential or single-ended voltage while minimizing signal-dependent short-term and long-term drift. The open-loop buffer may be a replica of the closed-loop buffer, reducing the effect of a signal coupled on the voltage reference lines. The reference voltage circuit may be adapted for a switched capacitor ADC.