An Offset Calibration Technique for CIS Column-Parallel SAR ADCs Using Memory

An Offset Calibration Technique for CIS Column-Parallel SAR ADCs Using Memory

Lee, J. (TU Delft Electronic Instrumentation)
Theuwissen, A.J.P.A.M. (TU Delft Electronic Instrumentation; Harvest Imaging, Belgium)

2022

A column-parallel 10-bit SAR ADC for high-speed image sensors has been implemented. A fast offset calibration technique using memory is proposed to compensate for the offset mismatch, accompanied by an ADC designed for a narrow space the size of a single column pitch. The memory accumulates the variation of the offset to track the offset within two cycles. After applying the offset calibration technique, the offset variation of the ADC measured in each column is improved from 4.27LSB to 0.39LSB. The fixed-pattern noise (FPN) is also improved from 4.14LSB to 0.34LSB. This calibration method covers an offset range of ±32LSB. The implemented ADC achieves a maximum speed of 500kS/s. The maximum frame rate of the sensor is 3000fps. The power consumption of the sensor, excluding the LVDS interface, is 71mW. This sensor is designed in a TowerJazz CIS 180nm process with one poly four metal. The supply voltage of the analog and digital domains is 3.3V and 1.8V, respectively.

http://resolver.tudelft.nl/uuid:4962b282-62a7-44ac-8da1-f961fd6a97a4

https://doi.org/10.2352/EI.2022.34.7.ISS-155

2023-07-01

IS and T International Symposium on Electronic Imaging Science and Technology, 34 (7)

IS and T International Symposium on Electronic Imaging: Imaging Sensors and Systems, ISS 2022, 2022-01-17 → 2022-01-26, Virtual, Online

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

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© 2022 J. Lee, A.J.P.A.M. Theuwissen