Isolated Sigma-Delta Modulator Data Sheet AD7401 FEATURES GENERAL DESCRIPTION 1 20 MHz maximum external clock rate The AD7401 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 Analog Devices, 2 LSB INL typical at 16 bits Inc., iCoupler technology. The AD7401 operates from a 5 V 3.5 V/C maximum offset drift power supply and accepts a differential input signal of 200 mV On-board digital isolator (320 mV full-scale). The analog input is continuously sampled On-board reference by the analog modulator, eliminating the need for external sample- Low power operation: 20 mA maximum at 5.25 V and-hold circuitry. The input information is contained in the 40C to +105C operating range output stream as a density of ones with a data rate up to 20 MHz. 16-lead SOIC package The original information can be reconstructed with an appropriate Safety and regulatory approvals digital filter. The serial input/output can use a 5 V or a 3 V UL recognition supply (VDD2). 5000 V rms for 1 minute per UL 1577 The serial interface is digitally isolated. High speed CMOS, CSA Component Acceptance Notice 5A combined with monolithic air core transformer technology, VDE Certificate of Conformity means the on-chip isolation provides outstanding performance DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 characteristics, superior to alternatives such as optocoupler devices. V = 891 V peak IORM The device contains an on-chip reference. The AD7401 is offered APPLICATIONS in a 16-lead SOIC and has an operating temperature range of 40C to +105C. AC motor controls Data acquisition systems An internal clock version, AD7400, is also available. A/D + opto-isolator replacements 1 Protected by U.S. Patents 5,952,849 6,873,065 and 7,075,329. FUNCTIONAL BLOCK DIAGRAM V V DD1 DD2 AD7401 V + IN - ADC V IN UPDATE WATCHDOG ENCODE DECODE MDAT REF CONTROL LOGIC WATCHDOG UPDATE DECODE MCLKIN ENCODE GND GND 1 2 Figure 1. Rev. F 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 20062018 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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T/H UF B 05851-001AD7401 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................9 Applications ....................................................................................... 1 Terminology .................................................................................... 12 General Description ......................................................................... 1 Theory of Operation ...................................................................... 13 Functional Block Diagram .............................................................. 1 Circuit Information .................................................................... 13 Revision History ............................................................................... 2 Analog Input ............................................................................... 13 Specifications ..................................................................................... 3 Differential Inputs ...................................................................... 14 Timing Specifications .................................................................. 4 Digital Filter ................................................................................ 15 Insulation and Safety Related Specifications ............................ 5 Applications Information .............................................................. 17 Regulatory Information ............................................................... 5 Grounding and Layout .............................................................. 17 DIN V VDE V 0884-10 (VDE V 0884-10) Insulation Evaluating the AD7401 Performance ...................................... 17 Characteristics .............................................................................. 6 Insulation Lifetime ..................................................................... 17 Absolute Maximum Ratings ............................................................ 7 Outline Dimensions ....................................................................... 18 ESD Caution .................................................................................. 7 Ordering Guide .......................................................................... 18 Pin Configuration and Function Descriptions ............................. 8 REVISION HISTORY 4/2018Rev. E to Rev. F 9/2007Rev. A to Rev. B Changes to Table 3 and Table 4 ....................................................... 5 Updated VDE Certification Throughout ...................................... 1 Changes to Table 6 ............................................................................. 7 12/2015Rev. D to Rev. E Changes to Ordering Guide .......................................................... 18 12/2006Rev. 0 to Rev. A Changes to Features and General Description .............................. 1 7/2011Rev. C to Rev. D Changes to Table 1 ............................................................................. 3 Changes to Minimum External Air Gap (Clearance) Parameter, Changes to Table 2 ............................................................................. 4 Table 3 and Minimum External Tracking (Creepage) Parameter, Changes to Table 6 ............................................................................. 7 Table 3 ................................................................................................ 5 Changes to Table 8 ............................................................................. 8 Changes to Figure 5 Pin 1 Description, Table 8 and Pin 7 Changes to Circuit Information Section ..................................... 13 Description, Table 8 .......................................................................... 8 Changes to Figure 27 ...................................................................... 15 1/2011Rev. B to Rev. C 1/2006Revision 0: Initial Version Changes to Features Section............................................................ 1 Changes to Input-to-Output Momentary Withstand Voltage Parameter, Table 3, UL Column, Table 4, and Note 1, Table 4 ........ 5 Changes to Ordering Guide ............................................................ 18 Rev. F Page 2 of 18