1-GHz, 17.5-mW, 8-bit Subranging ADC Using Offset-Cancelling Charge-Steering Amplifier

Kenichi OHHATA  

IEICE TRANSACTIONS on Electronics   Vol.E97-C   No.4   pp.289-297
Publication Date: 2014/04/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E97.C.289
Type of Manuscript: Special Section PAPER (Special Section on Solid-State Circuit Design,---,Architecture, Circuit, Device and Design Methodology)
analog-to-digital converter,  offset cancellation,  charge-steering amplifier,  capacitive averaging,  resistor ladder,  

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A high-speed and low-power 8-bit subranging analog-to-digital converter (ADC) based on 65-nm CMOS technology was fabricated. Rather than using digital foreground calibration, an analog-centric approach was adopted to reduce power dissipation. An offset cancelling charge-steering amplifier and capacitive-averaging technique effectively reduce the offset, noise, and power dissipation of the ADC. Moreover, the circuit used to compensate the kickback noise current from the comparator can also reduce the power dissipation. The reference-voltage generator for the fine ADC is composed of a fine ladder and a capacitor providing an AC signal path. This configuration reduces the power dissipation of the selection signal drivers for the analog multiplexer. A test chip fabricated using 65-nm digital CMOS technology achieved a high sampling rate of 1GHz, a low power dissipation of 17.5mW, and a figure of merit of 118fJ/conv.-step.