Title :
A 21-bit read-out IC employing dynamic element matching with 0.037% gain error
Author :
Wu, Rong ; Huijsing, Johan H. ; Makinwa, Kofi A A
Author_Institution :
Electron. Instrum. Lab., Delft Univ. of Technol., Delft, Netherlands
Abstract :
A 21-bit read-out IC (ROIC) with ±40mV full scale for interfacing bridge transducers and thermocouples has been realized in a 0.7μm CMOS process. The ROIC consists of a current-feedback instrumentation amplifier (CFIA) and a switched-capacitor (SC) ΣΔ ADC. To improve its gain accuracy, dynamic element matching (DEM) was applied to the input and feedback transconductors of the CFIA. However, the common-mode (CM) dependency of these transconductors limits the achievable gain accuracy. To enhance their CM immunity, threshold-boosting and impedance-balancing techniques have been applied. These techniques enable the ROIC to achieve a typical CMRR of 140dB and a worst-case gain error of 0.037%. Compared to recent work 10dB higher CMRR and 3.2× less gain error has been achieved for the same power consumption.
Keywords :
CMOS digital integrated circuits; analogue-digital conversion; delta-sigma modulation; instrumentation amplifiers; readout electronics; switched capacitor networks; thermocouples; transducers; CFIA; CM dependency; CM immunity; CMOS process; DEM; ROIC; SC ΣΔ ADC; bridge transducers; common-mode dependency; current-feedback instrumentation amplifier; dynamic element matching; feedback transconductors; gain accuracy; gain error; impedance-balancing technique; read-out IC; size 0.7 mum; switched-capacitor ΣΔ ADC; thermocouples; threshold-boosting technique; Accuracy; Bridge circuits; Gain; Integrated circuits; Transducers; Transistors;
Conference_Titel :
Solid State Circuits Conference (A-SSCC), 2011 IEEE Asian
Conference_Location :
Jeju
Print_ISBN :
978-1-4577-1784-0
DOI :
10.1109/ASSCC.2011.6123647
