Vlsi memory with an improved sense amplifier with dummy bit lines for

Abstract

The operation of the sense amplifier in a VLSI memory is improved by providing dummy bit lines corresponding to the ON state and OFF state of the memory cells, averaging the voltage on the dummy bit lines, and comparing that average to the bit line voltage to generate a differential sense output. Leakage currents and voltages common to both the dummy bit lines and selected bit line are thus cancelled out. Sense amplifiers incorporating this advantage may also be used in combination with a dynamic latch which is selectively disconnected from the memory array at all times other than during a memory cycle to avoid noise interference. Dummy word lines used in combination with dummy predecoder and decoder are used to make on-chip determinations of the transition points when an address signal is valid and complete. The actual initiation of the addressing of the memory may then be triggered according to a modeled transition point within each memory circuit. The worst ON state and OFF state voltages on dummy bit lines are used in a trigger circuit to generate a trigger signal for use in sense amplifiers which will reliably indicate when a valid sense decision can be made taking into consideration the individual process parameters and operating conditions of the actual memory circuit.