Title :
A 630μW zero-crossing-based ΔΣ ADC using switched-resistor current sources in 45nm CMOS
Author :
Musah, Tawfiq ; Kwon, Sunwoo ; Lakdawala, Hasnain ; Soumyanath, Krishnamurthy ; Moon, Un-Ku
Author_Institution :
Sch. of EECS, Oregon State Univ., Corvallis, OR, USA
Abstract :
A delta-sigma analog-to-digital converter employs zero-crossing-based integrators to achieve low power operation at 50 MHz sampling rate. Switched resistors, used as current sources, provide good dynamic current matching, eliminating the need for common-mode feedback circuits. The effect of the switched resistors on the linearity of the zero-crossing-based integrator is discussed. Also, a unidirectional 2-phase charging scheme is proposed to improve input signal swing and reduce overshoot voltage. Test chip implemented in a 45 nm LP digital CMOS achieves 54.3 dB DR, 52.5 dB SNR, and 47.7 dB SNDR at 0.833 MHz input while dissipating 630 muW from a 1.1 V supply.
Keywords :
CMOS digital integrated circuits; analogue-digital conversion; constant current sources; delta-sigma modulation; switched current circuits; delta-sigma analog-to-digital converter; digital CMOS process; dynamic current matching; frequency 0.833 MHz; frequency 50 MHz; power 630 muW; sampling rate; size 45 nm; switched-resistor current sources; unidirectional 2-phase charging scheme; voltage 1.1 V; zero-crossing-based DeltaSigma ADC; zero-crossing-based integrators; Analog-digital conversion; Circuit testing; Feedback circuits; Linearity; Resistors; Sampling methods; Switching circuits; Voltage;
Conference_Titel :
Custom Integrated Circuits Conference, 2009. CICC '09. IEEE
Conference_Location :
San Jose, CA
Print_ISBN :
978-1-4244-4071-9
Electronic_ISBN :
978-1-4244-4073-3
DOI :
10.1109/CICC.2009.5280909
