15.3 An a-IGZO asynchronous delta-sigma modulator on foil achieving up to 43dB SNR and 40dB SNDR in 300Hz bandwidth

Amorphous IGZO (a-IGZO) TFTs fabricated on flexible large-area substrates provide better mobility than a-Si or organic counterparts and good uniformity. These features make a-IGZO TFTs an attractive technology for large-area sensing (e.g. strain, pressure, IR), low-cost RFIDs augmented with sensors and monitoring of biopotentials. In this context, it is crucial to accurately transform analogue sensor signals in a robust representation. The most common choice is a synchronous digital word, but a two-level PWM representation is another interesting possibility. Binary PWM can be transmitted on wire or via RF amplitude modulation with high immunity to noise and interferers.