18-Bit, 1.5 LSB INL, 400 kSPS PulSAR Differential ADC in MSOP/LFCSP Data Sheet AD7690 FEATURES APPLICATION EXAMPLE +2.5V TO +5V +5V 18-bit resolution with no missing codes Throughput: 400 kSPS INL: 0.75 LSB typical, 1.5 LSB maximum (6 ppm of FSR) VIO +1.8V TO VDD Dynamic range: 102 dB at 400 kSPS REF VDD IN+ SDI Oversampled dynamic range: 125 dB at 1 kSPS SCK 3- OR 4-WIRE 10V, 5V, ... INTERFACE Noise-free code resolution: 20 bits at 1 kSPS SDO (SPI, DAISY CHAIN, CS) IN GND CNV Effective resolution: 22.7 bits at 1 kSPS ADA4941-1 SINAD: 101.5 dB at 1 kHz AD7690 THD: 125 dB at 1 kHz Figure 2. True differential analog input range: VREF 0 V to V with V up to VDD on both inputs REF REF Table 1. MSOP, LFCSP/SOT-23 14-/16-/18-Bit PulSAR ADC No pipeline delay 400 kSPS 100 250 to 1000 ADC Single-supply 5 V operation with Type kSPS kSPS 500 kSPS kSPS Driver 1.8 V/2.5 V/3 V/5 V logic interface 18-Bit True AD7691 AD7690 AD7982 ADA4941 Proprietary serial interface Differential AD7982 ADA4841 SPI/QSPI/MICROWIRE/DSP compatible 16-Bit True AD7684 AD7687 AD7688 ADA4941 Daisy-chain multiple ADCs and busy indicator Differential AD7693 ADA4841 Power dissipation 16-Bit Pseudo AD7680 AD7685 AD7686 AD7980 ADA4841 Differential AD7683 AD7694 4.25 W at 100 SPS 14-Bit Pseudo AD7940 AD7942 AD7946 ADA4841 4.25 mW at 100 kSPS Differential Standby current: 1 nA 10-lead package: MSOP (MSOP-8 size) and 3 mm 3 mm LFCSP (SOT-23 size) GENERAL DESCRIPTION Pin-for-pin compatible with LFCSP/MSOP PulSAR ADCs 1 The AD7690 is an 18-bit, successive approximation, analog-to- APPLICATIONS digital converter (ADC) that operates from a single power supply, VDD. It contains a low power, high speed, 18-bit sampling ADC Battery-powered equipment with no missing codes, an internal conversion clock, and a Data acquisition versatile serial interface port. On the CNV rising edge, it Seismic data acquisition systems samples the voltage difference between the IN+ and IN pins. DVMs The voltages on these pins swing in opposite phase between 0 V Instrumentation and REF. The reference voltage, REF, is applied externally and Medical instruments can be set up to the supply voltage. 1.5 POSITIVE INL = +0.42LSB NEGATIVE INL = 0.6LSB The power of the AD7690 scales linearly with the throughput. 1.0 The SPI-compatible serial interface also features the ability, using the SDI input, to daisy-chain several ADCs on a single, 0.5 3-wire bus and provides an optional busy indicator. It is compatible 0 with 1.8 V, 2.5 V, 3 V, or 5 V logic, using the separate VIO supply. The AD7690 is housed in a 10-lead MSOP or a 10-lead LFCSP 0.5 with operation specified from 40C to +85C. 1.0 1 Protected by U.S. Patent 6,703,961. 1.5 0 65536 131072 196608 262144 CODE Figure 1. Integral Nonlinearity vs. Code Rev. C 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 20062014 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. INL (LSB) 05792-025 05792-001AD7690 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Driver Amplifier Choice ........................................................... 14 Applications ....................................................................................... 1 Single-to-Differential Driver .................................................... 15 Application Example ........................................................................ 1 Voltage Reference Input ............................................................ 15 General Description ......................................................................... 1 Power Supply ............................................................................... 16 Revision History ............................................................................... 2 Supplying the ADC from the Reference .................................. 16 Specifications ..................................................................................... 3 Digital Interface .......................................................................... 16 Timing Specifications ....................................................................... 5 CS Mode, 3-Wire Without Busy Indicator ............................. 17 Absolute Maximum Ratings ............................................................ 6 CS Mode, 3-Wire With Busy Indicator ................................... 18 ESD Caution .................................................................................. 6 CS Mode, 4-Wire Without Busy Indicator ............................. 19 Pin Configurations and Function Descriptions ........................... 7 CS Mode, 4-Wire With Busy Indicator ................................... 20 Terminology ...................................................................................... 8 Chain Mode Without Busy Indicator ...................................... 21 Typical Performance Characteristics ............................................. 9 Chain Mode with Busy Indicator ............................................. 22 Theory of Operation ...................................................................... 12 Application Hints ........................................................................... 23 Circuit Information .................................................................... 12 Layout .......................................................................................... 23 Converter Operation .................................................................. 12 Evaluating the AD7690 Performance ...................................... 23 Typical Connection Diagram.................................................... 13 Outline Dimensions ....................................................................... 24 Analog Inputs .............................................................................. 14 Ordering Guide .......................................................................... 24 REVISION HISTORY Changes to Gain Error in Table 2 .................................................... 3 7/14Rev. B to Rev. C Changed QFN (LFCSP) to LFCSP .............................. Throughout Change to Gain Error Temperature Drift in Table 2 .................... 3 Changes to Features Section............................................................ 1 Change to Zero Temperature Drift in Table 2 ............................... 3 Added Patent Note, Note 1 .............................................................. 1 Changes to Power Dissipation in Table 3 ....................................... 4 Changes to Evaluating the AD7690 Performance Section ........ 23 Change to Conversion Time: CNV Rising Edge to Data Updated Outline Dimensions ....................................................... 24 Available in Table 4............................................................................ 5 Changes to Ordering Guide .......................................................... 24 Change to Acquisition Time in Table 4 .......................................... 5 Changes to Figure 12......................................................................... 9 7/11Rev. A to Rev. B Change to Figure 22 Caption ........................................................ 11 Changes to Common-Mode Input Range Min Parameter ......... 3 Changes to Circuit Information Section ..................................... 12 Added EPAD Note to Figure 6 and Table 6 ................................... 7 Change to Table 7 ........................................................................... 13 Updated Outline Dimensions ....................................................... 24 Change to Endnote 1 of Figure 26 ................................................ 13 Changes to Ordering Guide .......................................................... 24 Added Figure 29 ............................................................................. 14 Changes to Driver Amplifier Choice Section ............................. 14 3/07Rev. 0 to Rev. A Change to Evaluating the AD7690s Performance Section ....... 23 Removed Endnote Regarding QFN Package .................. Universal Updated Outline Dimensions ....................................................... 24 Changes to Features .......................................................................... 1 Changes to Ordering Guide .......................................................... 24 Changes to Table 1 ............................................................................ 1 Changes to Figure 2 .......................................................................... 1 4/06Revision 0: Initial Version Rev. C Page 2 of 24