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

In this work we present a fully integrated first order continuous-time <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">Δ Σ</tex></formula> 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 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">μ</tex> </formula> A from a 15 V power supply. As sub-blocks of the ADC, we also present a <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">Vₜ</tex> </formula> -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 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">Vₜ</tex></formula> -insensitive design strategy and use high-pass filters for offset cancellation. The active area is 13 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">\, ×</tex></formula> 20 mm <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">²</tex></formula> .