Pre-charge circuit and method for memory devices with shared sense amplifiers

A pre-charge circuit for a memory device having a sense amplifier shared between right and left banks of memory cells and a method of pre-charging the shared sense amplifier. The circuit is operated according to the method of the invention such that the sense amplifier is always pre-charged from the side that was previously active. The circuit includes right and left bank isolation transistor pairs connected between the shared sense amplifiers and the right and left banks. The isolation transistor pairs are controlled by a flip flop having a left bank state and a right bank state and complementary left and right outputs that turn off the left isolation transistor pair and turn on the right pair during row operations to the right and vice-versa. The flip-flop is kept in the right bank state after a row operation to the right bank so that the sense amplifier is pre-charged from the right after row operations to the right and the flip-flop is kept in the left bank state after a row operation to the left so that the sense amplifier is pre-charged from the left after row operations to the left.