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This paper presents an amplitude-shift-keying (ASK) demodulator for RF identification tags, which can be embedded on panel displays. The ASK demodulator was implemented in 3-mum low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT) technology. Since the threshold voltages of LTPS TFTs are higher than CMOS transistors, the conventional demodulator implementation will degrade the demodulator sensitivity significantly. The novel full-wave demodulator circuit was proposed to resolve the issue of high threshold voltage and reduce the ripples of the demodulated envelope. Operated at 8 V, the demodulator consumes 1.6 mW of power. The input carrier frequency was tested up to 13.56 MHz, and the highest ASK modulated data rate is 100 kb/s. The circuit size of the LTPS TFT demodulator is 500 mum times 450 mum.

The low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT) is an emerging technology to manufacture active matrix liquid crystal displays. With the TFT's maximum frequency of oscillation fmax exceeding 3.5 GHz, it becomes feasible to develop integrated circuits (ICs) in LTPS TFT technology to facilitate system on panel or system on display. This paper investigates the LTPS TFT characteristics for developing RF ICs. The dc and ac equivalent-circuit models were developed for LTPS TFT RF integrated-circuit design. A phase-locked loop (PLL) was demonstrated using the 3-μm LTPS TFT technology. The supply voltage and power consumption of the PLL are 8.4 V and 25 mW, respectively. The operation frequency range of the TFT PLL is from 2 to 10 MHz, and the measured root-mean-square jitter is 235 ps.

Low temperature polycrystalline silicon (LTPS) thin film transistor (TFT) is an emerging technology to manufacture active matrix liquid crystal displays (AMLCDs). With its maximum frequency of oscillation f max reaching beyond 1 GHz, it becomes feasible to develop integrated circuits in LTPS TFT technology to facilitate system on panel or system on display. This paper investigates the LTPS TFT characteristics for developing RFID tags. An equivalent circuit model was proposed for LTPS TFT RFIC design. An ASK demodulator for the RFID tag was demonstrated using 3µm LTPS TFT technology. The demodulator can operate at the carrier frequency of 13.56 MHz and the highest data rate is 100 kb/s.