The
amplifier circuit (1) includes a differential pair of PMOS transistors at input (P3, P4), whose source receives a current from a
current source (3). The gate of the first
transistor (P3) of the pair defines a non-inverting input (XOUT) and the gate of the second
transistor (P4) of the pair defines an inverting input (XIN). A drain of the first
transistor (P3) of the differential pair is connected to a
diode connected NMOS transistor (N2) of a first
current mirror (N1, N2), and a drain of the second transistor (P4) of the differential pair is connected to a
diode connected NMOS transistor (N3) of a second
current mirror (N3, N4). A
diode connected PMOS transistor (P2) of a third
current mirror is connected to the drain of a second NMOS transistor (N4) of the second current mirror, while a drain of a second PMOS transistor (P1) of the third current mirror is connected to the drain of a second NMOS transistor (N1) of the first current mirror to define a first output (OUT1), which is inverted by a reverser (N5, P7) to supply an inverted output
signal (OUT) capable of varying rail to rail. A first complementary NMOS transistor (N6) is connected in the form of a reverser with the first PMOS transistor (P3) of the differential pair. A second complementary NMOS transistor (N7) is connected in the form of a reverser with the second MOS transistor (P4) of the differential pair.