Ultra-Low Voltage Analog Design Techniques for Nanoscale CMOS Technologies

This paper reviews the challenges and opportunities for ultra-low voltage analog integrated circuit design. The continuing scaling of CMOS technology feature sizes forces a proportional reduction of the supply voltage. The ultra-low supply voltages, down to 0.5 V, projected for the nanoscale CMOS technologies requires drastic changes in the basic circuit topologies used in analog integrated circuits. We explore the combined use of the gate and body terminal of the MOS transistor for signal input or bias control. We illustrate several true-low voltage OTA design and biasing techniques in a fully integrated 0.5 V varactor-C active filter implemented in a standard 0.18 μm CMOS technology.