High-PSRR low-power single supply OTA

A CMOS single supply operational transconductance amplifier (OTA) is reported. It has high power supply rejection capabilities over the entire gain bandwidth. The OTA is fabricated using the AMI 0.5 m CMOS process. Measurements show power supply rejection ratio (PSRR) of 120 dB to 10 kHz. At 10 MHz, PSRR is 40 dB. The high performance PSRR is achieved using a high impedance current source and two noise reduction techniques. The OTA offers very low current consumption of 25 A from a 3.3 V supply. It is suitable for applications such as low drop out voltage regulators.