A 1.3 V op/amp in standard 0.7 /spl mu/m CMOS with constant g/sub m/ and rail-to-rail input and output stages

A fundamental analog building block is the operational amplifier. A low-voltage CMOS op amp must operate with supply voltages down to 1.5 V. The circuit architecture must maintain typical performance of a generic op amp. Other main features are: rail to rail input voltage range with constant g; rail to rail output voltage range; low-power consumption; high DC voltage gain; large GBW; high CMRR and PSRR; high slew rate etc. To realise this, the authors present a chip which uses 0.7 /spl mu/m CMOS technology with 1.2 /spl mu/m minimum channel length and standard 0.7 V thresholds. The circuit operates down to 1.3 V, the lowest supply voltage that can be achieved with threshold voltages of about 0.7 V.