An On-Line Calibration Technique for Mismatch Errors in High-Speed DACs
- Resource Type
- Periodical
- Authors
- Catteau, B.; Rombouts, P.; Raman, J.; Weyten, L.
- Source
- IEEE Transactions on Circuits and Systems I: Regular Papers IEEE Trans. Circuits Syst. I Circuits and Systems I: Regular Papers, IEEE Transactions on. 55(7):1873-1883 Aug, 2008
- Subject
- Components, Circuits, Devices and Systems
Calibration
Switches
Least squares approximation
Error correction
Circuits
Adaptive estimation
Low pass filters
Computer errors
Computer simulation
Application software
Current steering
digital–analog conversion
digital calibration
LMS
redundant signed digit (RSD) coding
- Language
- ISSN
- 1549-8328
1558-0806
In this paper a novel online calibration technique for high-speed DACs is presented. The approach consists of two elements. The first element is the use of a redundant signed digit (RSD) scheme for the selection of the current sources. This enables a fully digital correction. The second element consists of an adaptive estimation of the correction terms by an LMS algorithm. For this purpose the DAC output signal is low-pass filtered and digitized by an accurate but low-speed calibration ADC. By replicating this analog signal path in the digital domain, the errors can be calculated and used to update the correction weights. The dynamic behavior and the accuracy of the adaptive calibration loop are analyzed both theoretically and through computer simulations, and it is shown that this way a greatly improved accuracy can be obtained.