Patent ID: 7782664

Claim:
In a memory having a plurality of non-volatile memory cells and a reference cell, the reference cell for providing a predetermined reference current for reading a selected memory cell of the plurality of non-volatile memory cells, a method for trimming the reference cell, the method comprising: biasing the reference cell to establish a threshold voltage of the reference cell to a predetermined voltage, wherein biasing the reference cell further comprises biasing a control gate, a source terminal, a drain terminal, and a substrate terminal of the reference cell with a predetermined set of bias conditions, wherein the reference cell will gain or lose charge toward an asymptotic state of charge that no longer changes significantly after a predetermined operating time under the predetermined set of bias condition; determining a reference cell bias voltage for causing the reference cell to provide the predetermined reference current for the established threshold voltage; and providing the reference cell bias voltage to the reference cell during a read operation of the plurality of non-volatile memory cells.