16-Bit, 1.5 LSB INL, 250 kSPS PulSAR Differential ADC in MSOP Data Sheet AD7687 FEATURES TYPICAL APPLICATION CIRCUIT 0.5V TO 5V 2.5 TO 5V 16-bit resolution with no missing codes Throughput: 250 kSPS INL: 0.4 LSB typ, 1.5 LSB max (23 ppm of FSR) VREF VIO 1.8V TO VDD Dynamic range: 96.5 dB REF VDD 0 SDI SNR: 95.5 dB at 20 kHz IN+ SCK AD7687 3- OR 4-WIRE INTERFACE THD: 118 dB at 20 kHz IN (SPI, DAISY CHAIN, CS) SDO VREF True differential analog input range GND CNV 0 V REF 0 V to V with V up to VDD on both inputs REF REF No pipeline delay Figure 1. Single-supply 2.3 V to 5.5 V operation with 1.8 V/2.5 V/3 V/5 V logic interface Proprietary serial interface: SPI/QSPI/MICROWIRE/DSP compatible Daisy-chain multiple ADCs and BUSY indicator Power dissipation 1.35 mW at 2.5 V/100 kSPS, 4 mW at 5 V/100 kSPS, and 1.4 W at 2.5 V/100 SPS Standby current: 1 nA 10-lead MSOP and 10-lead, 3 mm 3 mm LFCSP Pin-for-pin compatible with AD7685, AD7686, and AD7688 APPLICATIONS Battery-powered equipment Data acquisitions Instrumentation Medical instruments Process controls GENERAL DESCRIPTION 1 The AD7687 is a 16-bit, charge redistribution, successive The SPI-compatible serial interface also features the ability to approximation, analog-to-digital converter (ADC) that operates daisy-chain several ADCs on a single 3-wire bus and provides from a single power supply, VDD, between 2.3 V to 5.5 V. It an optional BUSY indicator by means of the SDI pin. It is contains a low power, high speed, 16-bit sampling ADC with no compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic using the separate missing codes, an internal conversion clock, and a versatile supply VIO. serial interface port. The device also contains a low noise, wide The AD7687 comes in a 10-lead MSOP or a 10-lead LFCSP bandwidth, short aperture delay track-and-hold circuit. On the with operation specified from 40C to +85C. CNV rising edge, the AD7687 the samples the voltage difference between IN+ and IN pins, which can range from V to +V . REF REF Table 1. MSOP, LFCSP/SOT-23 16-Bit PulSAR ADC The reference voltage, V , is applied externally and can be set REF Type 100 kSPS 250 kSPS 500 kSPS up to the supply voltage. True Differential AD7684 AD7687 AD7688 Pseudo AD7683 AD7685 AD7686 The power consumption of the device scales linearly with Differential/Unipolar AD7694 throughput. Unipolar AD7680 1 Protected by U.S. Patent 6,703,961. Rev. E 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 20052015 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. 02972-002AD7687 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Driver Amplifier Choice ........................................................... 17 Applications ....................................................................................... 1 Single-to-Differential Driver .................................................... 17 Typical Application Circuit ............................................................. 1 Voltage Reference Input ............................................................ 17 General Description ......................................................................... 1 Power Supply ............................................................................... 17 Revision History ............................................................................... 3 Supplying the ADC from the Reference .................................. 18 Specifications ..................................................................................... 4 Digital Interface .......................................................................... 18 Timing Specifications .................................................................. 6 CS Mode, 3-Wire Without BUSY Indicator ........................... 19 Absolute Maximum Ratings ............................................................ 8 CS Mode, 3-Wire with BUSY Indicator .................................. 20 Thermal Resistance ...................................................................... 8 CS Mode, 4-Wire Without BUSY Indicator ........................... 21 ESD Caution .................................................................................. 8 CS Mode, 4-Wire with BUSY Indicator .................................. 22 Pin Configurations and Function Descriptions ........................... 9 Chain Mode Without BUSY Indicator .................................... 23 Terminology .................................................................................... 10 Chain Mode with BUSY Indicator ........................................... 24 Typical Performance Characteristics ........................................... 11 Applications Information .............................................................. 25 Theory of Operation ...................................................................... 14 Layout .......................................................................................... 25 Circuit Information .................................................................... 14 Evaluating the Performance of the AD7687 ............................... 25 Converter Operation .................................................................. 14 Outline Dimensions ....................................................................... 26 Typical Connection Diagram ................................................... 15 Ordering Guide .......................................................................... 26 Analog Input ............................................................................... 16 Rev. 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