18-Bit, 670 kSPS, Differential Programmable Input PulSAR ADC Data Sheet AD7634 FEATURES FUNCTIONAL BLOCK DIAGRAM TEMP REFBUFIN REF REFGND VCC VEE DVDD DGND Multiple pins/software-programmable input ranges 5 V (10 V p-p), +10 V (20 V p-p), 5 V (20 V p-p), OVDD AGND AD7634 10 V (40 V p-p) REF OGND AVDD AMP SERIAL DATA Pins or serial SPI-compatible input ranges/mode selection REF PDREF PORT Throughput SERIAL PDBUF CONFIGURATION 670 kSPS (warp mode) PORT 18 IN+ SWITCHED D 17:0 CAP DAC 570 kSPS (normal mode) IN BUSY 450 kSPS (impulse mode) RD INL: 1.5 LSB typical, 2.5 LSB maximum (9.5 ppm of FSR) PARALLEL CS CLOCK INTERFACE CNVST 18-bit resolution with no missing codes D0/OB/2C PD CONTROL LOGIC AND Dynamic range: 102.5 dB D1/A0 CALIBRATION CIRCUITRY RESET SNR: 101 dB 2 kHz D2/A1 THD: 112 dB 2kHz iCMOS process technology WARP IMPULSE BIPOLAR TEN MODE0 MODE1 5 V internal reference: typical drift 3 ppm/C TEMP output Figure 1. No pipeline delay (SAR architecture) Table 1. 48-Lead PulSAR Selection Parallel (18-/16-/8-bit bus) and serial 5 V/3.3 V interface 100 to 500 to 570 to SPI-/QSPI-/MICROWIRE-/DSP-compatible Res 250 570 1000 >1000 Power dissipation Input Type (Bits) (kSPS) (kSPS) (kSPS) (kSPS) 180 mW 670 kSPS, warp mode Bipolar 14 AD7951 28 mW 100 kSPS, impulse mode Differential 14 AD7952 10 mW 1 kSPS, impulse mode Bipolar Pb-free, 48-lead LQFP and 48-Lead LFCSP (7 mm 7 mm) Unipolar 16 AD7651 AD7650 AD7653 AD7660 AD7652 AD7667 APPLICATIONS AD7661 AD7664 CT scanners AD7666 High dynamic data acquisition Bipolar 16 AD7610 AD7665 AD7612 AD7663 AD7671 - replacement Spectrum analysis Differential 16 AD7675 AD7676 AD7677 AD7621 Unipolar AD7622 Medical instruments AD7623 Instrumentation 16 Simultaneous/ AD7654 Process controls Multichannel AD7655 Unipolar GENERAL DESCRIPTION Differential 18 AD7678 AD7679 AD7674 AD7641 The AD7634 is an 18-bit charge redistribution successive Unipolar AD7643 approximation register (SAR), architecture analog-to- Differential 18 AD7631 AD7634 digital converter (ADC) fabricated on Analog Devices, Inc.s Bipolar iCMOS high voltage process. The device is configured through hardware or via a dedicated write-only serial configuration port for input range and operating mode. The AD7634 contains a high speed 18-bit sampling ADC, an internal conversion clock, an internal reference (and buffer), error correction circuits, and both serial and parallel system interface ports. A falling edge on CNVST samples the fully differential analog inputs on IN+ and IN. The AD7634 features four different analog input ranges and three different sampling modes. Operation is specified from 40C to +85C. Rev. B 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 20072012 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 06406-001AD7634 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Driver Amplifier Choice ........................................................... 21 Applications ....................................................................................... 1 Voltage Reference Input/Output .............................................. 22 General Description ......................................................................... 1 Power Supplies ............................................................................ 22 Functional Block Diagram .............................................................. 1 Conversion Control ................................................................... 23 Revision History ............................................................................... 2 Interfaces.......................................................................................... 24 Specif icat ions ..................................................................................... 3 Digital Interface .......................................................................... 24 Timing Specifications .................................................................. 5 Parallel Interface ......................................................................... 24 Absolute Maximum Ratings ............................................................ 7 Serial Interface ............................................................................ 25 ESD Caution .................................................................................. 7 Master Serial Interface ............................................................... 25 Pin Configuration and Function Descriptions ............................. 8 Slave Serial Interface .................................................................. 27 Typical Performance Characteristics ........................................... 12 Hardware Configuration ........................................................... 29 Terminology .................................................................................... 16 Software Configuration ............................................................. 29 Theory of Operation ...................................................................... 17 Microprocessor Interfacing ....................................................... 30 O ver vie w ...................................................................................... 17 Application Information ................................................................ 31 Converter Operation .................................................................. 17 Layout Guidelines....................................................................... 31 Modes of Operation ................................................................... 17 Evaluating Performance ............................................................ 31 Transfer Functions...................................................................... 18 Outline Dimensions ....................................................................... 32 Typical Connection Diagram ................................................... 19 Ordering Guide .......................................................................... 32 Analog Inputs .............................................................................. 20 REVISION HISTORY 12/12Rev. A to Rev. B Changes to Power Sequencing Section ........................................ 23 Updated Outline Dimensions ....................................................... 32 Changes to Ordering Guide .......................................................... 32 3/11Rev. 0 to Rev. A Changes to Resolution Parameter, Table 2 .................................... 3 Changes to Figure 4 and Table 6 ..................................................... 8 Added Exposed Pad Notation to Outline Dimensions ............. 32 1/07Revision 0: Initial Version Rev. B Page 2 of 32