Low Power, Unity Gain, Fully Differential Amplifier and ADC Driver Data Sheet AD8476 FEATURES FUNCTIONAL BLOCK DIAGRAM Very low power 330 A supply current Extremely low harmonic distortion 10k 126 HD2 at 10 kHz 128 HD3 at 10 kHz 10k AD8476 10k Fully differential or single-ended inputs/outputs Differential output designed to drive precision ADCs 10k Drives switched capacitor and - ADCs Rail-to-rail outputs VOCM pin adjusts output common mode Robust overvoltage up to 18 V beyond supplies NOTES 1. NC = NO CONNECT. High performance DO NOT CONNECT TO THIS PIN. Suitable for driving 16-bit converter up to 250 kSPS Figure 1. 8-Lead MSOP 39 nV/Hz output noise 1 ppm/C gain drift maximum 200 V maximum output offset 10 V/s slew rate 6 MHz bandwidth INP 1 12 NC Single supply: 3 V to 18 V 10k 10k Dual supplies: 1.5 V to 9 V INP 2 11 OUT AD8476 10k INN 3 10 +OUT APPLICATIONS 10k INN 4 9 VOCM ADC driver Differential instrumentation amplifier building block Single-ended-to-differential converter Battery-powered instruments NOTES 1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN. Figure 2. 16-Lead LFCSP GENERAL DESCRIPTION The AD8476 is a very low power, fully differential precision switched capacitor front-end circuits of many ADCs with amplifier with integrated gain resistors for unity gain. It is an ideal minimal error. choice for driving low power, high performance ADCs as a Unlike many differential drivers on the market, the AD8476 is single-ended-to-differential or differential-to-differential a high precision amplifier. With 200 V maximum output amplifier. It provides a precision gain of 1, common-mode level offset, 39 nV/Hz noise, and 102 dB THD + N at 10 kHz, the shifting, low temperature drift, and rail-to-rail outputs for AD8476 pairs well with low power, high accuracy converters. maximum dynamic range. Considering its low power consumption and high precision, the The AD8476 also provides overvoltage protection from large slew-enhanced AD8476 has excellent speed, settling to 16-bit industrial input voltages up to 23 V while operating on a dual 5 V precision for 250 kSPS acquisition times. supply. Power dissipation on a single 5 V supply is only 1.5 mW. The AD8476 is available in space-saving 16-lead, 3 mm 3 mm The AD8476 works well with SAR, -, and pipeline converters. LFCSP and 8-lead MSOP packages. It is fully specified over the The high current output stage of the part allows it to drive the 40C to +125C temperature range. Rev. B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 20112012 Analog Devices, Inc. All rights reserved. INN 1 8 INP +V 2 7 V S S VOCM 3 6 NC +OUT 4 5 OUT 10195-001 10195-002 +V 5 16 V S S +V 6 15 V S S 14 V +V 7 S S +V 8 13 V S SAD8476 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Overview ..................................................................................... 17 Applications ....................................................................................... 1 Circuit Information .................................................................... 17 Functional Block Diagram .............................................................. 1 DC Precision ............................................................................... 17 General Description ........................................................................... 1 Input Voltage Range ................................................................... 18 Revision History ............................................................................... 2 Driving the AD8476................................................................... 18 Specifications ..................................................................................... 3 Power Supplies ............................................................................ 18 Absolute Maximum Ratings ............................................................ 5 Applications Information .............................................................. 19 Thermal Resistance ...................................................................... 5 Typical Configuration ................................................................ 19 Maximum Power Dissipation ..................................................... 5 Single-Ended-to-Differential Conversion ............................... 19 ESD Caution .................................................................................. 5 Setting the Output Common-Mode Voltage .......................... 19 Pin Configuration and Function Descriptions ............................. 6 Low Power ADC Driving .......................................................... 20 Typical Performance Characteristics ............................................. 8 Outline Dimensions ....................................................................... 21 Terminology .................................................................................... 16 Ordering Guide .......................................................................... 22 Theory of Operation ...................................................................... 17 REVISION HISTORY 5/12Rev. A to Rev. B Added LFCSP Throughout .............................................................. 1 Added Harmonic Distortion Values to Features Section and Changed Bandwidth from 5 MHz to 6 MHz ................................ 1 Changed 3 dB Small Signal Bandwidth from 5 MHz to 6 MHz, Changed HD2 from 120 dB to 126 dB, and Changed HD3 from 122 dB to 128 dB, Table 1 .................................................. 3 Changes to Figure 17 and Figure 19 ............................................. 10 Changes to Figure 25 ...................................................................... 11 Changes to Figure 30 ...................................................................... 12 Added Low Power ADC Driving Section ................................... 20 Updated Outline Dimensions ....................................................... 21 Changes to Ordering Guide .......................................................... 22 11/11Rev. 0 to Rev. A Changes to Table 1 ............................................................................ 3 Changes to Typical Performance Characteristics ......................... 7 Added Figure 39 Renumbered Sequentially .............................. 13 Added Table 5 .................................................................................. 18 Removed Low Power ADC Driving Section ............................... 19 Removed Figure 52 ......................................................................... 19 10/11Revision 0: Initial Version Rev. B Page 2 of 24