0.5 V Variable Gain Amplifier Using Dynamic Threshold MOS for Ultra-Low Power Applications

Ultra-low-power and Ultra-low voltages are the stringent requirements for small-size battery-operated devices. This paper proposed Variable Gain Amplifier(VGA) using Dynamic Threshold MOS transistor (Combined Bulk-Gate Driven-DTMOS). The basic building block of the analog circuit operational transconductance amplifier(OTA) was designed with DTMOS as the first stage with cascaded current mirror as a load. The second stage utilized the Miller Capacitance Compensation method for stability. The closed-loop configurations with multiple capacitances at the input side are utilized for variable gain. The simulation was performed in a 180nm technology node with power dissipation of 8.35μW, gain range 19.9dB-35.25dB, Bandwidth 5.16kHz, and Gain Bandwidth Product(GBW) 353kHz. The Monte Carlo simulation was performed for process and temperature variation.