A 4-bit, 3.2 GSPS flash analog to digital converter with a new multiplexer based encoder

A 4-bit flash analog to digital converter with high speed, low power, and small area for system on chip(SoC) applications is presented. The proposed ADC is designed with BSIM4 90nm CMOS technology and 1.2V power supply. In comparison to the conventional analog comparators, it uses Threshold Inverter Quantization technique to generate comparators. The replacement results in a faster digital conversion and a reduction in power that make it suitable for battery powered applications. The TIQ comparator does not need a resistor ladder network because it uses built in reference voltage of the CMOS inverters for comparison. Proposed flash ADC uses a new mux based encoder which converts Thermometer code into Gray code. Gray codes are mainly used in glitches free fast circuit design and in communication for error correction in digital modulation techniques. The maximum sampling frequency of this ADC is 3.2GSPS. This ADC consumes 4.93mW power at 3.2GSPS. INL and DNL of proposed ADC are 0.775LSB and 0.15LSB respectively. The proposed A/D converter is suitable for mobile applications and other system on chip applications.