Patent ID: 7813182

Claim:
A semiconductor memory, comprising: a first load MOS transistor of a first conductivity type which has one end connected to a power supply and is diode-connected; nonvolatile memory cells which are connected between an other end of the first load MOS transistor and ground and have adjustable threshold voltages; a second load MOS transistor of the first conductivity type which has one end connected to the power supply, is diode-connected, and has the same size as the first load MOS transistor; nonvolatile reference cells which are connected between an other end of the second load MOS transistor and the ground and have adjustable threshold voltages; a third load MOS transistor of the first conductivity type which has one end connected to the power supply, has a gate connected to a gate of the second load MOS transistor, has the same size as the first load MOS transistor, and is fed with a current obtained by current mirroring a current passing through the second load MOS transistor; a first reference MOS transistor of a second conductivity type which is connected between an other end of the third load MOS transistor and the ground and is diode-connected; an amplifier input MOS transistor of the first conductivity type which has one end connected to the power supply, has a gate connected to the other end of the first load MOS transistor, has the same size as the first load MOS transistor, and composes a first-stage amplifier circuit; and an amplifier reference MOS transistor of the second conductivity type which is connected between an other end of the amplifier input MOS transistor and the ground, has the same size as the first reference MOS transistor, is fed with a current obtained by current mirroring a current passing through the first reference MOS transistor, and composes the first-stage amplifier circuit, wherein data stored in the memory cells is read based on a potential between the amplifier input MOS transistor and the amplifier reference MOS transistor, the potential being outputted from the first-stage amplifier circuit.