Balanced Modulator/Demodulator Data Sheet AD630 FEATURES FUNCTIONAL BLOCK DIAGRAM CM OFF CM OFF DIFF OFF DIFF OFF Recovers signal from 100 dB noise ADJ ADJ ADJ ADJ 2 MHz channel bandwidth 45 V/s slew rate BIAS 2.5k Low crosstalk: 120 dB at 1 kHz, 100 dB at 10 kHz R A IN AMP A Pin programmable, closed-loop gains of 1 and 2 CH A+ COMP 0.05% closed-loop gain accuracy and match CH A +V A +V S S 100 V channel offset voltage (AD630) 2.5k R B IN 350 kHz full power bandwidth V OUT AMP B B 10k CH B+ Chips available 10k V R CH B B 5k APPLICATIONS R A Balanced modulation and demodulation R F Synchronous detection CHANNEL COMP STATUS SEL B Phase detection B/A SEL A Quadrature detection Phase sensitive detection V S Lock in amplification Figure 1. Square wave multiplication Other features of the AD630 include pin programmable frequency GENERAL DESCRIPTION compensation optional input bias current compensation resistors, The AD630 is a high precision balanced modulator/demodulator common-mode and differential-offset voltage adjustment, and a that combines a flexible commutating architecture with the channel status output that indicates which of the two differential accuracy and temperature stability afforded by laser wafer trimmed inputs is active. thin film resistors. A network of on-board applications resistors provides precision closed-loop gains of 1 and 2 with 0.05% PRODUCT HIGHLIGHTS accuracy (AD630B). These resistors may also be used to accurately 1. The application flexibility of the AD630 makes it the best configure multiplexer gains of 1, 2, 3, or 4. External feedback choice for applications that require precisely fixed gain, enables high gain or complex switched feedback topologies. switched gain, multiplexing, integrating-switching The AD630 can be thought of as a precision op amp with two functions, and high speed precision amplification. independent differential input stages and a precision comparator 2. The 100 dB dynamic range of the AD630 exceeds that of that is used to select the active front end. The rapid response any hybrid or IC balanced modulator/demodulator and is time of this comparator coupled with the high slew rate and fast comparable to that of costly signal processing instruments. settling of the linear amplifiers minimize switching distortion. 3. The op amp format of the AD630 ensures easy implementation of high gain or complex switched feedback functions. The The AD630 is used in precision signal processing and instru- application resistors facilitate the implementation of most mentation applications that require wide dynamic range. When common applications with no additional parts. used as a synchronous demodulator in a lock-in amplifier 4. The AD630 can be used as a 2-channel multiplexer with gains configuration, the AD630 can recover a small signal from 100 dB of 1, 2, 3, or 4. The channel separation of 100 dB at 10 kHz of interfering noise (see the Lock-In Amplifier Applications approaches the limit achievable with an empty IC package. section). Although optimized for operation up to 1 kHz, the 5. Laser trimming of the comparator and amplifying channel circuit is useful at frequencies up to several hundred kilohertz. offsets eliminate the need for external nulling in most cases. Rev. G Document Feedback 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 20152016 Analog Devices, Inc. All rights reserved. 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. Technical Support www.analog.com 00784-001AD630 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Circuit Description .................................................................... 13 Applications ....................................................................................... 1 Other Gain Configurations ....................................................... 14 Functional Block Diagram .............................................................. 1 Switched Input Impedance ....................................................... 14 General Description ......................................................................... 1 Frequency Compensation ......................................................... 14 Product Highlights ........................................................................... 1 Offset Voltage Nulling ............................................................... 15 Revision History ............................................................................... 2 Channel Status Output .............................................................. 15 Specif icat ions ..................................................................................... 3 Applications Information .............................................................. 16 Absolute Maximum Ratings ............................................................ 4 Balanced Modulator ................................................................... 16 Thermal Resistance ...................................................................... 4 Balanced Demodulator .............................................................. 16 Chip Availability ........................................................................... 4 Precision Phase Comparator .................................................... 16 ESD Caution .................................................................................. 4 Precision Rectifier Absolute Value ........................................... 16 Pin Configurations and Function Descriptions ........................... 5 LVDT Signal Conditioner ......................................................... 17 Typical Performance Characteristics ............................................. 9 AC Bridge .................................................................................... 17 Test Circuits ..................................................................................... 11 Lock-In Amplifier Applications ............................................... 18 Theory of Operation ...................................................................... 12 Outline Dimensions ....................................................................... 19 Two Ways To Look At The AD630 .......................................... 12 Ordering Guide .......................................................................... 20 How the AD630 Works .............................................................. 12 REVISION HISTORY 12/2016Rev. F to Rev. G 6/2004Rev. D to Rev. E Changes to Figure 1 .......................................................................... 1 Changes to Ordering Guide ............................................................. 3 Changes to Figure 31 ...................................................................... 17 Replaced Figure 12 ............................................................................ 9 Changes to Figure 35 ...................................................................... 18 Changes to AC Bridge Section ......................................................... 9 Replaced Figure 13 ......................................................................... 10 7/2015Rev. E to Rev. F Changes to Lock-In Amplifier Applications ............................... 10 Updated Format .................................................................. Universal Updated Outline Dimensions ....................................................... 11 Changes to Features Section, General Description Section, Product Highlights Section, and Figure 1 ..................................... 1 6/2001Rev. C to Rev. D Added Applications Section ............................................................ 1 Changes to Specification Table ........................................................ 2 Changes to Table 3 ............................................................................ 4 Changes to Thermal Characteristics ............................................... 3 Added Table 4 Renumbered Sequentially .................................... 5 Changes to Ordering Guide ............................................................. 3 Added Figure 4 Renumbered Sequentially and Table 5 ............. 6 Changes to Pin Configurations ....................................................... 3 Added Figure 5 and Table 6 ............................................................. 7 Changes to Outline Dimensions .................................................. 11 Added Table 7 .................................................................................... 8 Changes to Figure 7, Figure 8, and Figure 9 ................................. 9 Changes to Figure 13, Figure 14, and Figure 15 ......................... 10 Added Test Circuits Section and Figure 16 to Figure 19 ........... 11 Added Theory of Operation Section ........................................... 12 Change to Figure 24 ....................................................................... 13 Updated Outline Dimensions ....................................................... 19 Changes to Ordering Guide .......................................................... 20 Rev. G Page 2 of 20