AD7400: Isolated Sigma-Delta Modulator - Analog Devices - #1

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Isolated Sigma-Delta Modulator AD7400 Rev. C 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 rights of third parties that may result from its use. Specifications subject to change without notice. No 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. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2006–2011 Analog Devices, Inc. All rights reserved. FEATURES 10 MHz clock rate Second-order modulator 16 bits no missing codes ±2 LSB INL typical at 16 bits 3.5 ìV/°C maximum offset drift On-board digital isolator On-board reference Low power operation: 18 mA maximum at 5.25 V -40°C to +105°C operating range 16-lead SOIC package Safety and regulatory approvals UL recognition 5000 V rms for 1 minute per UL 1577 CSA Component Acceptance Notice #5A VDE Certificate of Conformity DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 VIORM = 891 V peak APPLICATIONS AC motor controls Data acquisition systems A/D + opto-isolator replacements GENERAL DESCRIPTION The AD74001 is a second-order, sigma-delta (Ó-Ä) modulator that converts an analog input signal to a high speed, 1-bit data stream with on-chip digital isolation based on Analog Devices, Inc. iCoupler® technology. The AD7400 operates from a 5 V power supply and accepts a differential input signal of ±200 mV (±320 mV full scale). The analog input is continuously sampled by the analog modulator, eliminating the need for external sample-and-hold circuitry. The input information is contained in the output stream as a density of ones with a data rate of 10 MHz. The original information can be reconstructed with an appropriate digital filter. The serial I/O can use a 5 V or a 3 V supply (VDD2). The serial interface is digitally isolated. High speed CMOS, combined with monolithic air core transformer technology, means the on-chip isolation provides outstanding performance characteristics superior to alternatives such as optocoupler devices. The part contains an on-chip reference. The AD7400 is offered in a 16-lead SOIC and has an operating temperature range of -40°C to +105°C. An external clock version, AD7401, is also available. 1 Protected by U.S. Patents 5,952,849; 6,873,065; and 7,075,329. Other patents pending. FUNCTIONAL BLOCK DIAGRAM 04718-001VIN+VDD1VDD2VIN–Ó-Ä ADCCONTROL LOGICAD7400BUFT/HREFUPDATEGND1GND2MDATMCLKOUTENCODEENCODEDECODEDECODEWATCHDOGWATCHDOGUPDATE Figure 1.