Title :
Radix-based digital calibration method for pipelined ADCs with signal-dependent dithering
Author :
Keke Zhu ; Lee, Albert
Author_Institution :
Sch. of Microelectron., Shanghai Jiao Tong Univ., Shanghai, China
fDate :
Oct. 29 2012-Nov. 1 2012
Abstract :
This paper presents a new digital calibration method for a 14-bit 140MS/s pipelined analog-to-digital converter (ADC). Signal-dependent Pseudo-random Noise (PN) sequences are injected into the first 3.5-bit multiplying digital-to-analog converter (MDAC) without interrupting its normal conversion operation to extract the radix term, which includes finite opamp gain, settling error and capacitor mismatch. Compared to conventional fixed magnitude PN dithering, signal-dependent dithering greatly improves the signal-to-noise plus distortion (SNDR) of the ADC and reduces the calibration time. By using proposed method, the ADC achieves a peak SNDR of 81.5dB and spurious-free dynamic range (SFDR) of 102.8dB with 31.6MHz input at 140MS/s and the ENOB is improved from 6.5 bits to 13.25 bits.
Keywords :
analogue-digital conversion; calibration; digital arithmetic; digital-analogue conversion; operational amplifiers; random sequences; calibration time; capacitor mismatch; finite opamp gain; fixed magnitude PN dithering; frequency 31.6 MHz; multiplying digital-to-analog converter; normal conversion operation; pipelined ADC; pipelined analog-to-digital converter; radix term; radix-based digital calibration method; settling error; signal-dependent dithering; signal-dependent pseudo-random noise sequences; signal-to-noise plus distortion; spurious-free dynamic range; word length 14 bit; word length 3.5 bit; Analog-digital conversion; Calibration; Capacitors; Gain measurement; Mathematical model; Noise; Simulation; digital calibration; pipelined ADC; radix-based method; signal-dependent dithering;
Conference_Titel :
Solid-State and Integrated Circuit Technology (ICSICT), 2012 IEEE 11th International Conference on
Conference_Location :
Xi´an
Print_ISBN :
978-1-4673-2474-8
DOI :
10.1109/ICSICT.2012.6467896