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.