Title :
Digital background auto-calibration of DAC non-linearity in pipelined ADCs
Author :
Kinyua, Martin ; Maloberti, Franco ; Gosney, William
Author_Institution :
Texas Instruments Inc., Dallas, TX, USA
Abstract :
In this paper, a digital background auto-calibration method that computes mismatch between the elements of the inter-stage multiplying-digital-to-analog converter (MDAC) as commonly employed in pipelined analog-to-digital converters (ADCs) and then applies a linearizing algorithm in the digital domain is described. The calibration does not interrupt the normal operation of the ADC and is performed periodically, thus inherently able to track changes in the operating conditions of the device, a major limitation of the one-time calibration approaches. This scheme requires an extra MDAC element and a reference element. The MDAC mismatch is digitized by the succeeding stages of the pipeline and subsequently digitally extracted. The accuracy of the calibration algorithm depends on the number of clock periods used for each calibration session. Longer sessions lead to better accuracy with the trade-off being additional digital circuitry. System simulation results demonstrative validity of the approach.
Keywords :
analogue-digital conversion; calibration; digital-analogue conversion; pipeline processing; DAC nonlinearity; MDAC mismatch; calibration session; clock periods; digital background auto-calibration; digital circuitry; digital domain; digital extraction; linearizing algorithm; multiplying digital-to-analog converter; one-time calibration; pipelined ADC; reference element; system simulation; Analog-digital conversion; Calibration; Capacitors; Circuit simulation; Clocks; Fluctuations; Harmonic distortion; Instruments; Linearity; Pipelines;
Conference_Titel :
Circuits and Systems, 2004. ISCAS '04. Proceedings of the 2004 International Symposium on
Print_ISBN :
0-7803-8251-X
DOI :
10.1109/ISCAS.2004.1328119