VLSI implementation of the threshold inverter quantization (TIQ) technique for CMOS flash A/D converter applications

This study introduces a new technique, the “Threshold Inverter Quantizer” (TIQ), for flash analog-to-digital (A/D) converter applications. The TIQ is based on a CMOS inverter cell, in which the voltage transfer characteristics (VTC) are changed by systematic transistor sizing. As a result, a significant improvement of speed and reduction of area and power consumption is achieved.; This study is mainly based on three major parts. Firstly, an analog quantizer, which leads to implementation of a 6-bit-200 MS/s CMOS Flash A/D converter, has been designed and verified by using HSPICE circuit simulator. Simulation results also show that a 4-bit flash converter with 300 MHz sampling rate can be achieved by the TIQ technique in 0.8μ CMOS n-well technology.; Secondly, complete A/D converters based on three and four bits versions of TIQ (TIQ3 and TIQ4) have been designed and fabricated successfully in 2μ n-well CMOS technology as a supporting work for the proposed quantizer. DC and AC simulations and laboratory test results are presented.; Finally detailed analysis of the performance of the TIQ approach with respect to process parameter, temperature and power supply variations, and MOS transistor mismatching is performed. Each investigation result is evaluated in light of previous research from the literature.