A high performance sense amplifier for a 5 V dynamic RAM

Increasing dynamic RAM cell density and the use of a single low-voltage power supply have made it mandatory to store the full power supply voltage in the cell and to be able to detect smaller signals reliably with the initial sense amplifier. The authors present a circuit design approach that restores the cell to a full V/SUB DD/ `1' level, preamplifies the initial charge imbalance before sensing by conventional techniques, and is used in the Fairchild 64K design. Design requirements and a detailed analysis of the amplifier are presented along with simulated results, followed by performance data. The circuit analysis shows how the key design parameters should be chosen and the effects of clock timing variations on the performance of the sense amplifier.