Weighted_resistance_DAC

Weighted_resistance_ - A Configurable CMOS Voltage DAC for Multichannel Detector Systems M N Ericson S S Frank C L Britton Jr M S Emery J S Sam A L

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A Configurable CMOS Voltage DAC for Multichannel Detector Systems' M. N. Ericson, S. S. Frank, C. L. Britton, Jr., M. S. Emery, J. Sam, A. L. Wintenberg Oak Ridge National Laboratory, Oak Ridge, TN 37831-6006 Abstract A CMOS voltage DAC has been developed for integration into multiple front-end electronics ASICs associated with the PHENIX detector located at the RHIC accelerator of Brookhaven National Laboratory. The topology allows wide-range output programmability by selection of an offset voltage and on-chip resistor and transistor sizing. The DAC is trimless and requires no external components, making it ideal for highly integrated collider detector systems. Errors associated with on-chip bias are minimized using a topology that implements a ratiometric relationship which compensates for absolute resistance value changes and is limited only by errors in the on-chip matching of MOSFETs and resistive devices. Temperature-induced errors associated with the integrated resistors are also minimized by the circuit topology and monolithic construction. All reference voltages and currents are derived using a single regulated voltage supply. This paper presents the general DAC architecture and design method, discusses on-chip matching issues and tradeoffs associated with device sizing and monolithic layout, and presents measured performance of various gate length DACs fabricated in a 1.2ym CMOS process including integral non- linearity, differential nonlinearity, and slope and offset errors. I. INTRODUCTION Highly integrated front-end electronics are commonplace in present-day collider detector systems [ 11. Future requirements for higher spatial resolution and lower energy particle detection will only increase the need for improvement in electronic function and implementation. In order to meet this need, electronics will need to continue technological growth in the following areas: reduced power, reduced circuit area, higher level of integration (which implies reduction or elimination of off-chip components), and low- noise performance. Contemporary monolithic DAC designs rely on precision elements to ensure accuracy and linearity [2,3]. Precision passive elements are obtained by either tight process control, resistive trimming, or the use of external precision components. These methods typically increase the fabrication cost or increase the circuit implementation size. This paper presents a CMOS monolithic, compatible DAC that is ideal for use in high density collider detector systems. Keys to its usefulness include small area, low-power consumption, no need for external components or trimming, 'Research sponsored by the U.S. Department of Energy and performed at Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corporation for the U.S. Department of Energy under Contract No. DE-AC05-960R22464.
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This note was uploaded on 03/19/2008 for the course EE 577B taught by Professor Bhatti during the Spring '08 term at USC.

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Weighted_resistance_ - A Configurable CMOS Voltage DAC for Multichannel Detector Systems M N Ericson S S Frank C L Britton Jr M S Emery J S Sam A L

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