High Precision 10 V Reference AD688 FUNCTIONAL BLOCK DIAGRAM FEATURES NOISE +10V OUT 10 V tracking outputs V REDUCTION HIGH A3 IN SENSE Kelvin connections 7 6 4 3 Low tracking error: 1.5 mV +10V OUT Low initial error: 2.0 mV A3 1 FORCE R B Low drift: 1.5 ppm/C A1 AD688 Low noise: 6 V p-p 10V OUT 14 SENSE R1 R4 Flexible output force and sense terminals High impedance ground sense 10V OUT A4 15 R2 FORCE Wide body SOIC and CERDIP packages R5 2 +V R6 S R3 GENERAL DESCRIPTION A2 16 V S The AD688 is a high precision 10 V tracking reference. Low 5 9 10 8 12 11 13 tracking error, low initial error, and low temperature drift give GAIN GND NC V BAL NC A4 IN LOW the AD688 reference absolute 10 V accuracy performance SENSE ADJ ADJ +IN NC = NO CONNECT previously unavailable in monolithic form. The AD688 uses a proprietary ion-implanted buried Zener diode, and laser wafer Figure 1. drift trimming of high stability thin-film resistors to provide outstanding performance. The AD688 includes the basic reference cell and three additional amplifiers. The amplifiers are laser-trimmed for low offset and low drift and maintain the accuracy of the reference. PRODUCT HIGHLIGHTS The amplifiers are configured to allow Kelvin connections to 1. Precision Tracking. The AD688 offers precision tracking the load and/or boosters for driving long lines or high current 10 V Kelvin output connections with no external loads, delivering the full accuracy of the AD688 where it is components. Tracking error is less than 1.5 mV and fine- required in the application circuit. trim is available for applications requiring exact symmetry The low initial error allows the AD688 to be used as a system between the +10 V and 10 V outputs. reference in precision measurement applications requiring 2. Accuracy. The AD688 offers 12-bit absolute accuracy 12-bit absolute accuracy. In such systems, the AD688 can without any user adjustments. Optional fine-trim provide a known voltage for system calibration the cost of connections are provided for applications requiring higher periodic recalibration can therefore be eliminated. precision. The fine-trimming does not alter the operating Furthermore, the mechanical instability of a trimming conditions of the Zener or the buffer amplifiers and thus potentiometer and the potential for improper calibration can be does not increase the temperature drift. eliminated by using the AD688 and calibration software. 3. Low output noise. Output noise of the AD688 is low The AD688 is available in commercial version. Specified over o o typically 6 V p-p. A pin is provided for broadband noise the 40 C to +85 C temperature range, the AD688 is offered in filtering using an external capacitor. wide body 16-lead SOIC and 16-lead CERDIP packages, 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 rights of third parties that may result from its use. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Specifications subject to change without notice. No license is granted by implication Tel: 781.329.4700 www.analog.com 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 2005 Analog Devices, Inc. All rights reserved. 00815-001AD688 TABLE OF CONTENTS Specifications..................................................................................... 3 Turn On Time................................................................................8 Absolute Maximum Ratings............................................................ 4 Temperature Performance............................................................9 ESD Caution.................................................................................. 4 Kelvin Connections.......................................................................9 Pin Configuration and Function Descriptions............................. 5 Dynamic Performance............................................................... 11 Theory of Operation ........................................................................ 6 Bridge Driver Circuit ................................................................. 12 Applications....................................................................................... 7 Outline Dimensions ....................................................................... 13 Calibration..................................................................................... 7 Ordering Guide .......................................................................... 13 Noise Performance and Reduction ............................................ 8 REVISION HISTORY 3/05Rev. A to Rev. B Updated Format..................................................................Universal Added AD688ARWZ .........................................................Universal Removed AD688SQ ...........................................................Universal Updated Outline Dimensions ....................................................... 13 Changes to Ordering Guide .......................................................... 13 Rev. B Page 2 of 16