A 180nm CMOS low power latched comparator for NMR applications

This paper presents a CMOS comparator design for Nuclear Magnetic Resonance (NMR) applications. Basically the design is based on CMOS Operational Transconductance Amplifier (OTA) technique with reduced cascode current mirror circuit for proper biasing. The present Magnetic Resonance Imagers (MRI) operates at a magnetic field of 1.5 Tesla which corresponds to the resonance frequency of the nuclei being 64 MHz. Hence the proposed comparator architecture involves the use of a sampler and a comparator (quantizer) for this frequency specification. The overall CMOS comparator design is realised in 180nm CMOS technology which occupies an active area of 44.39 × 34.25 μm2 and consumes a power of 118.5 uW from a 1.5V power supply.