Experimental investigation of the minimum signal for reliable operation of DRAM sense amplifiers

Discusses the measurement of the minimum sense signal necessary for proper operation of the dynamic RAM (DRAM) sense amplifier. The minimum sense signal has been investigated experimentally by using a test structure that is basically a modified cross-coupled sense amplifier with 16-Mb DRAM feature sizes. Measured 5 sigma values of 27 mV correspond to variation in gate length, whereas 10 mV is found for bit-line capacitance asymmetries. The way that the minimum sense signal is affected by the different trigger-pulse slopes was investigated. A simple but illustrative analysis of the effect of device mismatches is developed and the measured values are compared with theoretical limits.