A Fully Integrated ΔΣ ADC in Organic Thin-Film Transistor Technology on Flexible Plastic Foil

In this work we present a fully integrated first order continuous-time Delta Sigma ADC made in a pentacene-based dual-gate organic thin-film transistor technology on flexible plastic foil. The ADC achieves a precision of 26.5 dB at a clock speed of 500 Hz and draws 100 mu A from a 15 V power supply. As sub-blocks of the ADC, we also present a V-t-insensitive single-stage differential amplifier with 10 kHz GBW, a 3-stage operational amplifier, an integrator, a comparator and a level shifter. The circuits are designed following a strict V-t-insensitive design strategy and use high-pass filters for offset cancellation. The active area is 13 x 20 mm(2).