Mixed-Signal Building Blocks for Communication Systems Using Flexible Oxide TFT Technology

This article reports two important mixed-signal building blocks using unipolar oxide thin-film transistors (TFTs) on a 30- $\mu \text{m}$ -thick polymide substrate, which find potential application in communication systems. These blocks include a low-voltage bootstrapped (BS) switch and a latch-type comparator designed using a device channel length of $2~\mu \text{m}$ . Functional demonstration of these blocks has been carried out from measurements under normal ambient conditions with a load of 10 $\text{M}\Omega ||12$ pF at a supply voltage ( $V_{\text {DD}}$ ) not exceeding 3 V. While the BS switch shows a linear ON-resistance of 40 $\text{k}\Omega $ , at a $V_{\text {DD}}$ of 2 V, without any voltage drop across it, the proposed comparator has shown a very low offset of 10 mV with a decision time of $4~\mu \text{s}$ . These blocks help in expanding the application of oxide TFT technology in communication systems to design the binary amplitude-shift keying (BASK) modulator and demodulator circuits.