Designing and Layouting Single Supply fully differential Low Voltage 4Bit Flash Analog to Digital Quantizer for Double side input Rang

In this paper a new high 4bit flash analog to digital (ADC) is presented that can be used in a N bit Flash ADC converter as continuous and discrete timeSigma-delta modulator quantizer. It has been implemented and layouted and tested by CADENCE software in 0.18μm CMOS technology. Its main advantages are: it works withsingle supply and measure positive and negative input voltage range. Compact architecture based on MOStransistor only, without any passive components such asresistance ladder or switch capacitance, fully differential input and output voltages, operating at very low voltage. Itoperates at 300Msample/s, suitable for over sampled data converter. The simulation shows 3.8mW power consumption for the whole ADC. Simulation results of the circuit in a 0.025-mm CMOS process confirm the effectiveness of the approaches to considerably reduce thepower consumption of high-speed quantizer. Finally, the quantizer has been put a first order sigma-delta modulator analog to digital convertor (ADC) and has been tested. By this 4bit quantizer, we get 10DB improve in SNR of sigmadelta modulator rather than quantizer of ref [3]. Its result proofs our idea.

Designing and Layouting Single Supply fully differential Low Voltage 4Bit Flash Analog to Digital Quantizer for Double side input Rang Keywords:

Quantizer , Comparator , Latch , DAC , Layout , Sigma delta modulator