Low-power 8-bit Pipelined ADC with current mode Multiplying Digital-to-Analog Converter (MDAC)

Abstract: In order to convert the analog information in the digital domain, pipelined analog-to-digital converter (ADC) offers an optimum balance of resolution, speed, power consumption, size and design effort. In this thesis work we design and optimize a 8-bit pipelined ADC for low-power. The ADC has stage resolution of 1.5-bit and employ current mode multiplying analog-to-digital converter (MDAC). The main focus is to design and optimize the MDAC. Based on the analysis of "On current mode circuits" discussed in chapter 2, we design and optimize the MDAC circuit for the best possible effective number of bits (ENOB), speed and power consumption. Each of the first six stages consisting of Sample-and-Hold, 1.5-bit flash ADC and MDAC is realized at the circuit level. The last stage consisting of 2-bit flash ADC is also realized at circuit level. The delay logic for synchronization is implemented in Verilog-A and MATLAB. A first order digital error-correction algorithm is implemented in MATLAB. The design is simulated in UMC 0.18um technology in Cadence environment. The choice of technology is made as the target application for the ADC, 'X-ray Detector System' is designed in the same technology. The simulation results obtained in-term of ENOB and power consumption are satisfactory for the target application.