A non-volatile memory has a plurality of sense amplifiers for sensing a group of memory storage units in parallel, each of said plurality of sense amplifiers having properties dependent on operating environment and a set of control signals. A reference circuit having elements with properties representative of a typical member of the sense amplifiers is located in a common operating environment with the sense amplifiers. In use, the set of control signals, responsive to said elements operating in the operating environment, is generated such that the sense amplifiers are controlled to have their properties substantially insensitive to the operating environment.