Ultra low-voltage CMOS transconductance amplifiers

Simple and symmetrical ultra low-voltage current mode analog circuits and autozeroing amplifiers are presented. The low-voltage analog circuits are based on low-voltage inverters resembling precharge digital logic. Ultra low-voltage analog circuits can be operated at supply voltages down to 250 mV with rail-to-rail input and output swing. The output current of the ultra low-voltage symmetrical transconductance amplifier can be quite large due to a current boost technique. Ultra low-voltage analog circuits can be operated at supply voltages down to 250 mV with railto-rail input and output swing. The current headroom is 3 lA and the supply voltage is 300 mV. For supply voltages down to 300 mV simulated data shows that the maximum clock frequency is approximately 600 MHz.