Circuit design techniques for very low-voltage analog functional blocks using triple-tail cells

Novel circuit design techniques for very low-voltage analog functional blocks using triple-tail cells are presented. A triple-tail cell is operable on very low voltage because it possesses a very simple circuit structure, and it operates as a gain controllable differential amplifier and a tunable rectifier. It is very suitable for analog functional blocks, such as operational transconductance amplifiers (OTA's), four-quadrant analog multipliers, logarithmic intermediate-frequency (IF) amplifiers, and automatic gain control (AGC) amplifiers, to be realized using triple-tail cells with a small circuit scale. Therefore, a triple-tail cell is the most essential circuit for very low-voltage operation in signal processing. Furthermore, very low-voltage operation at a 1 V supply voltage and the fundamental characteristics of the basic circuits consisting of triple-tail cells, such a transconductance controllable OTA, four-quadrant analog multipliers, a logarithmic IF amplifier, and an AGC amplifier, were verified with transistor-arrays and discrete components on a breadboard.