A micropower OTA for digitally calibrated algorithmic ADCs

Abstract

The paper presents techniques to realize micropower OTAs using the inversion coefficient design methodology. Such OTAs find use in low speed moderate resolution algorithmic ADCs where use of digital calibration relaxes the analog performance requirements while simultaneously demanding low voltage operation to reduce the power dissipation of the added digital circuitry. A prototype switched OTA sample and hold and gain-by-two stages was fabricated in 0.5-µm CMOS. Measured results indicate that the fabricated prototype gain-by-two amplifier dissipates 30 µW at 1.5 V and shows a gain of 1.84 V/V when switched at 100 KHz.