Static method to negate offset voltages in CMOS operational amplifiers

摘要

Disclosed is a generator and method for using the generator to negate offset voltages in operational amplifiers. The generator includes an operational amplifier (op amp) whose input stage includes a current source coupled to a differential pair of input devices. The physical characteristics of the devices are such that an intentional offset voltage greater than the normal op amp offset voltage is provided in the input stage. The output terminal of the generator op amp is connected to the substrate terminal of one of the input devices. The offset voltages of other op amps can be negated by interconnecting the substrate terminal of one device in each input differential pair to the output terminal of the generator op amp and creating an intentional offset voltage in the input differential pair of each op amp.