TY - GEN
T1 - A hybrid SAR-VCO ΔΣ ADC with first-order noise shaping
AU - Sanyal, Arindam
AU - Ragab, Kareem
AU - Chen, Long
AU - Viswanathan, T. R.
AU - Yan, Shouli
AU - Sun, Nan
N1 - Publisher Copyright:
© 2014 IEEE.
PY - 2014/11/4
Y1 - 2014/11/4
N2 - A scaling-friendly, hybrid, two-stage ΔΣ ADC with a 5-bit SAR as first stage and a VCO as second stage is presented in this work. Since the VCO can provide fine quantization for small signals in the time-domain, it is used to directly quantize the SAR residue without OTA-based residue amplification. Also, having a small input swing obviates the need for VCO non-linearity calibration. The VCO phase overflow problem is solved by using a counter to record the number of overflows, thus allowing a variable sampling rate. Since the VCO phase and counter are never reset, the VCO's first-order noise-shaping capability is retained. A prototype ADC in an 180 nm process achieves 73 dB SNDR over 2.2 MHz bandwidth and consumes 5 mW from a 1.8V supply while sampling at 35 MHz.
AB - A scaling-friendly, hybrid, two-stage ΔΣ ADC with a 5-bit SAR as first stage and a VCO as second stage is presented in this work. Since the VCO can provide fine quantization for small signals in the time-domain, it is used to directly quantize the SAR residue without OTA-based residue amplification. Also, having a small input swing obviates the need for VCO non-linearity calibration. The VCO phase overflow problem is solved by using a counter to record the number of overflows, thus allowing a variable sampling rate. Since the VCO phase and counter are never reset, the VCO's first-order noise-shaping capability is retained. A prototype ADC in an 180 nm process achieves 73 dB SNDR over 2.2 MHz bandwidth and consumes 5 mW from a 1.8V supply while sampling at 35 MHz.
KW - analog to digital converters (ADC)
KW - noise shaping
KW - successive approximation register (SAR)
KW - two stage ADC
KW - voltage controlled oscillator (VCO)
UR - http://www.scopus.com/inward/record.url?scp=84928152159&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84928152159&partnerID=8YFLogxK
U2 - 10.1109/CICC.2014.6946082
DO - 10.1109/CICC.2014.6946082
M3 - Conference contribution
AN - SCOPUS:84928152159
T3 - Proceedings of the IEEE 2014 Custom Integrated Circuits Conference, CICC 2014
BT - Proceedings of the IEEE 2014 Custom Integrated Circuits Conference, CICC 2014
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 36th Annual Custom Integrated Circuits Conference - The Showcase for Integrated Circuit Design in the Heart of Silicon Valley, CICC 2014
Y2 - 15 September 2014 through 17 September 2014
ER -