Isolated Sigma-Delta Modulator Data Sheet AD7401A FEATURES GENERAL DESCRIPTION 1 20 MHz maximum external clock rate The AD7401A is a second-order, sigma-delta (-) modulator Second-order modulator that converts an analog input signal into a high speed, 1-bit data 16 bits, no missing codes stream with on-chip digital isolation based on the Analog 2 LSB INL typical at 16 bits Devices, Inc., iCoupler technology. The AD7401A operates 1 V/C typical offset drift from a 5 V power supply and accepts a pseudo-differential input On-board digital isolator signal of 250 mV (320 mV full scale). The analog input is On-board reference continuously sampled by the analog modulator, eliminating the 250 mV analog input range need for external sample-and-hold circuitry. The input Low power operation: 17 mA typical at 5.5 V information is contained in the output stream as a density of 40C to +125C operating range ones with a data rate of up to 20 MHz. The original information 16-lead SOIC package can be reconstructed with an appropriate digital filter. The Internal clock version: AD7400A serial I/O can use a 5 V or a 3.3 V supply (VDD2). Safety and regulatory approvals The serial interface is digitally isolated. High speed CMOS, UL recognition combined with Analog Devices, Inc., iCoupler technology , 5000 V rms for 1 minute per UL 1577 means the on-chip isolation provides outstanding performance CSA Component Acceptance Notice 5A characteristics, superior to alternatives such as optocoupler VDE Certificate of Conformity devices. The device contains an on-chip reference. The DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 AD7401A is offered in a 16-lead SOIC and has an operating V = 891 V peak IORM temperature range of 40C to +125C. Qualified for Automotive Applications APPLICATIONS AC motor controls Shunt current monitoring Data acquisition systems Analog-to-digital and opto-isolator replacements FUNCTIONAL BLOCK DIAGRAM V V DD1 DD2 AD7401A V + IN - ADC V IN UPDATE WATCHDOG ENCODE DECODE MDAT REF CONTROL LOGIC WATCHDOG UPDATE DECODE ENCODE MCLKIN GND GND 1 2 Figure 1. 1 Protected by U.S. Patents 5,952,849 6,873,065 and 7,075,329. Other patents pending. Rev. D 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 20082018 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 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Technical Support www.analog.com T/H BUF 07332-001AD7401A Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Theory of Operation ...................................................................... 14 Applications ....................................................................................... 1 Circuit Information .................................................................... 14 General Description ......................................................................... 1 Analog Input ............................................................................... 14 Functional Block Diagram .............................................................. 1 Differential Inputs ...................................................................... 15 Revision History ............................................................................... 2 Current Sensing Applications ................................................... 15 Specifications ..................................................................................... 3 Voltage Sensing Applications .................................................... 15 Timing Specifications .................................................................. 5 Digital Filter ................................................................................ 16 Insulation and Safety-Related Specifications ............................ 6 Applications Information .............................................................. 18 Regulatory Information ............................................................... 6 Grounding and Layout .............................................................. 18 DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 Insulation Evaluating the AD7401A Performance ................................... 18 Characteristics .............................................................................. 7 Insulation Lifetime ..................................................................... 18 Absolute Maximum Ratings ............................................................ 8 Outline Dimensions ....................................................................... 19 ESD Caution .................................................................................. 8 Ordering Guide .......................................................................... 19 Pin Configuration and Function Descriptions ............................. 9 Automotive Product ................................................................... 19 Typical Performance Characteristics ........................................... 10 Terminology .................................................................................... 13 REVISION HISTORY 1/2018Rev. C to Rev. D 1/2011Rev. 0 to Rev. A Changes to Features and General Description ............................. 1 Change to Features, UL Recognition Value ................................... 1 Change to Power Dissipation Parameter, Table 1 ......................... 4 Change to Table 3, Input-to-Output Momentary Withstand Changes to Table 3 and Table 4 ....................................................... 6 Voltage Value .................................................................................................. 6 Changes to Absolute Maximum Rating Section ........................... 8 Changes to Table 4, Isolation Voltage Value, and Endnote 1 ....... 6 Changes to Table 8 ............................................................................ 9 Changes to Terminology Section.................................................. 13 7/2008Revision 0: Initial Version Changes to Ordering Guide .......................................................... 19 Added Automotive Product Section ............................................ 19 7/2011Rev. B to Rev. C Changes to Minimum External Air Gap (Clearance) Parameter, Table 3 and Minimum External Tracking (Creepage) Parameter, Table 3 ................................................................................................ 6 Changes to Figure 5 Pin 1 Description, Table 8 and Pin 7 Description, Table 8 .......................................................................... 9 3/2011Rev. A to Rev. B Change to General Description Section ........................................ 1 Changes to Table 1 ............................................................................ 3 Rev. D Page 2 of 20