US Patent 7254077 Circuit and method for high speed sensing

A circuit and method for sensing a difference between a first signal, such as a signal from the source side of a memory cell, and a second signal, such as a signal from a reference dummy cell, includes developing first and second voltages respectively in response to the first and second signals, determining the time at which the second voltage developed in response to the second signal reaches a threshold level above a latch switching point, and latching a state of the first voltage and second voltage at the determined time using a latch circuit. The threshold level above the latch switching point is set so that potential mismatch in the components of the latch circuit is overcome prior to latching.