ADC Driver

The demand for hand-held mobile phones and their longer battery life-time motivates low-voltage integrated circuit design. Mobile video and high-definition television applications require high-speed, medium resolution, and low-power design specifications, which are the realm of pipelined and SAR ADCs. The SAR ADC has become increasingly popular as it is based on switching rather than amplifying, contains less hardware than other topologies and it scales well with technology. However, due to its inherent high input capacitance the design of the input driver is becoming more difficult, especially at lower technology nodes [24]. Further, the design of rail-to rail output amplifiers is also becoming increasingly difficult at lower technologies due to poor output impedance and higher threshold voltages. Logic circuits’ static power dissipation limit the scaling of threshold voltages of transistors. The noise requirements of an operational transconductance amplifier (OTA) design becomes increasingly more stringent for lower input voltage swings. Linearity requirements demand high overdrive voltages. On the other hand high overdrive voltages result in higher noise for the same current.