24-Bit, 8.5 mW, 109 dB, 128 kSPS/64 kSPS/32 kSPS ADCs AD7767 FEATURES GENERAL DESCRIPTION Oversampled successive approximation (SAR) architecture The AD7767/AD7767-1/AD7767-2 are high performance, High performance ac and dc accuracy, low power 24-bit, oversampled SAR analog-to-digital converters (ADCs). 115.5 dB dynamic range, 32 kSPS (AD7767-2) The AD7767/AD7767-1/AD7767-2 combine the benefits of a 112.5 dB dynamic range, 64 kSPS (AD7767-1) large dynamic range and input bandwidth, consuming 15 mW, 109.5 dB dynamic range, 128 kSPS (AD7767) 10.5 mW, and 8.5 mW power, respectively, and are contained in 118 dB THD a 16-lead TSSOP package. Exceptionally low power Ideal for ultralow power data acquisition (such as PCI- and 8.5 mW, 32 kSPS (AD7767-2) USB-based systems), the AD7767/AD7767-1/AD7767-2 10.5 mW, 64 kSPS (AD7767-1) provide 24-bit resolution. The combination of exceptional SNR, 15 mW, 128 kSPS (AD7767) wide dynamic range, and outstanding dc accuracy make the High dc accuracy AD7767/AD7767-1/AD7767-2 ideally suited for measuring 24 bits, no missing codes (NMC) small signal changes over a wide dynamic range. This is INL: 3 ppm (typical), 7.6 ppm (maximum) particularly suitable for applications where small changes on the Low temperature drift input are measured on larger ac or dc signals. In such an Zero error drift: 15 nV/C application, the AD7767/AD7767-1/AD7767-2 accurately Gain error drift: 0.4 ppm/C gather both ac and dc information. On-chip low-pass FIR filter The AD7767/AD7767-1/AD7767-2 include an on-board digital Linear phase response filter (complete with linear phase response) that acts to elimi- Pass-band ripple: 0.005 dB nate out-of-band noise by filtering the oversampled input Stop-band attenuation: 100 dB voltage. The oversampled architecture also reduces front-end 2.5 V supply with 1.8 V/2.5 V/3 V/3.6 V logic interface options antialias requirements. Other features of the AD7767 include a Flexible interfacing options SYNC PD Synchronization of multiple devices / (synchronization/power-down) pin, allowing the Daisy-chain capability synchronization of multiple AD7767 devices. The addition of Power-down function an SDI pin provides the option of daisy chaining multiple Temperature range: 40C to +105C AD7767 devices. The AD7767/AD7767-1/AD7767-2 operate from a 2.5 V supply APPLICATIONS using a 5 V reference. The devices operate from 40C to +105C. Low power PCI/USB data acquisition systems Low power wireless acquisition systems RELATED DEVICES Vibration analysis Table 1. 24-Bit ADCs Instrumentation Part No. Description High precision medical acquisition 1 AD7760 2.5 MSPS, 100 dB dynamic range, on-board differential FUNCTIONAL BLOCK DIAGRAM amp and reference buffer, parallel, variable decimation 1 AV AGND MCLK DV V DGND AD7762/ 625 kSPS, 109 dB dynamic range, on-board differential DD DD DRIVE AD7763 amp and reference buffer, parallel/serial, variable V decimation REF+ 1 V AD7764 312 kSPS, 109 dB dynamic range, on-board differential IN+ DIGITAL SUCCESSIVE amp and reference buffer, variable decimation (pin) FIR FILTER APPROXIMATION 1 ADC AD7765 156 kSPS, 112 dB dynamic range, on-board differential SYNC/PD V IN amp and reference buffer, variable decimation (pin) SERIAL INTERFACE 1 REFGND AND CS AD7766 128 kSPS, 109.5 dB, 15 mW, 16-bit INL, serial interface CONTROL LOGIC AD7767/ 1 AD7766-1 64 kSPS 112.5 dB, 10.5 mW, 16-bit INL, serial interface AD7767-1/ 1 AD7766-2 32 kSPS, 115.5 dB, 8.5 mW, 16-bit INL, serial interface AD7767-2 SCLK DRDY SDO SDI 1 Dynamic range at maximum output data rate. Figure 1. Rev. C 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. Fax: 781.461.3113 20072010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 06859-001AD7767 TABLE OF CONTENTS Features .............................................................................................. 1 Supply and Reference Voltages ................................................. 16 Applications ....................................................................................... 1 AD7767 Interface ........................................................................... 17 Functional Block Diagram .............................................................. 1 Initial Power-Up ......................................................................... 17 General Description ......................................................................... 1 Reading Data ............................................................................... 17 Related Devices ................................................................................. 1 Power-Down, Reset, and Synchronization ............................. 17 Revision History ............................................................................... 2 Daisy Chaining ............................................................................... 18 Specif icat ions ..................................................................................... 3 Reading Data in Daisy-Chain Mode ....................................... 18 Timing Specifications .................................................................. 5 Choosing the SCLK Frequency ................................................ 18 Timing Diagrams .......................................................................... 6 Daisy-Chain Mode Configuration and Timing Diagrams ... 19 Absolute Maximum Ratings ............................................................ 8 Driving the AD7767 ....................................................................... 20 ESD Caution .................................................................................. 8 Differential Signal Source ......................................................... 20 Pin Configuration and Function Descriptions ............................. 9 Single-Ended Signal Source ...................................................... 20 Typical Performance Characteristics ........................................... 10 Antialiasing ................................................................................. 21 Terminology .................................................................................... 14 Power Dissipation....................................................................... 21 Theory of Operation ...................................................................... 15 V Input Signal ....................................................................... 22 REF+ AD7767/AD7767-1/AD7767-2 Transfer Function ................ 15 Multiplexing Analog Input Channels ...................................... 22 Converter Operation .................................................................. 15 Outline Dimensions ....................................................................... 23 Analog Input Structure .............................................................. 16 Ordering Guide .......................................................................... 23 REVISION HISTORY 5/10Rev. B to Rev. C Changes to Pin 8 Description ......................................................... 9 Changes to Table 8 .......................................................................... 20 3/09Rev. A to Rev. B Changes to t Parameter, Table 3 .......................................... 5 SETTLING Changes to Table 7 .......................................................................... 17 1/09Rev. 0 to Rev. A Changes to Features Section............................................................ 1 Change to Intermodulation Distortion (IMD) Parameter and Integral Nonlinearity Parameter, Table 2 ................................. 3 Changes to Supply and Reference Voltages Section ................... 16 Changes to Choosing the SCLK Frequency Section .................. 18 Changes to Figure 24 ...................................................................... 12 Changes to Driving the AD7767 Section .................................... 20 Changes to Single-Ended Signal Source Section ........................ 20 Added Figure 41 Renumbered Sequentially .............................. 20 Change to Figure 42 ....................................................................... 21 Added Table 8 Renumbered Sequentially .................................. 20 Replaced V Input Signal Section ............................................ 22 REF+ Replaced Figure 46 ......................................................................... 22 8/07Revision 0: Initial Version Rev. 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