6-Bit Flash ADC for High speed Applications

This paper shows the implementation of a 6-bit Flash Analog to Digital Converter in 130-nm technology CMOS logic functions at 2.5-GSamples/s, used in most of DSP-based receiver. The FLSH ADC is equipped by variable gain amplifier (VGA), track-and-hold (T/H) circuit, a comparator array consist of 63 comparators, D Flip-Flops. A multiplexer logic is compared with the decoder using Full Adders in Wallace tree structure, with respect to hardware, critical path and power consumption. The Multiplexer logic is used to convert the 63-Bit Thermometer code into 6-Bit Binary code. Also integrated a on chip micro controller calibration, is used to monitor and compensate the nominal nonlinearity of the fine VGA and the resistor ladder. The ADC with 400mV of full scale voltage consumes 15-30 m W of power approximately from a 0.9V supply.