AD5422电压输出和4 mA至20 mA

电路笔记 CN-0077 连接/参考器件 AD5422 16位电流源与电压输出数模转换器 利用 ADI 公司产品进行电路 放心运用这些配套产品迅速完成设计。 欲获得更多信息和/或技术支持，请拨打 4006-100-006 或访问 www.analog.com/zh/circuits 。 Rev.0 “Circuits from the Lab” from Analog Devices have been designed and built by Analog Devices engineers. Standard engineering practices have been employed in the design and construction of each circuit, and their function and performance have been tested and verified in a lab environment at room temperature. However, you are solely responsible for testing the circuit and determining its suitability and applicability for your use and application. Accordingly, in no event shall Analog Devices be liable for direct, indirect, special, incidental, consequential or punitive damages due to any cause whatsoever connected to the use of any “Circuit from the Lab”. (Continued on last page) 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 ©2010 Analog Devices, Inc. All rights reserved. 利用 AD5422 提供 16 位电压输出和 4 mA 至 20 mA 输出简化解决 电路功能与优势 本电路利用单通道、16位、串行输入、单极性/双极性电压、 4 mA至 20 mA电流源 DAC AD5422，提供单极性/双极性电 压和 4 mA至 20 mA输出。它只需用产品 AD5422，所需外 部元件只有电源引脚和基准输入上的去耦电容，以及用于开 漏故障输出的上拉电阻。当电流输出端丧失兼容电压或 AD5422 温度过高时，开漏故障输出会予以警示。这款解决 方案具有很高的集成度，可节省成本和电路板空间。本电路 非常适合工业控制应用中的可编程逻辑控制器(PLC)和分布 式控制系统(DCS)。 电路描述 AD5422是一款低成本、精密、高度集成的 16位数模转换器， 提供可编程电流源和可编程电压输出，针对工业过程控制应 用的要求而设计。电压输出范围可通过编程设置为 0 V至+5 V、0 V至+10 V、−5 V至+5 V或−10 V至+10 V。电流输出 通过一个独立的引脚访问，可通过编程设置为 4 mA 至 20 mA、0 mA至 20 mA或 0 mA至 24 mA。AD5422内置一个 5 V、10 ppm/°C（最大值）基准电压源，从而可以进一步节省 成本和电路板空间。额定工作电压为：AVDD电源电压最高达 24 V，AVSS电源电压最高达−24 V。不过，AD5422能够以最 高 40 V的 AVDD电源电压工作。该器件含有 4.5 V片内稳压 输出（DVCC引脚），能够提供最大 5 mA源电流。这可以用 作上拉电阻的端电极，或者为数字电路供电，从而无需产生 逻辑电源电压。 图 1. AD5422的基本连接（原理示意图） CN-0077 电路笔记 (Continued from first page) "Circuits from the Lab" are intended only for use with Analog Devices products and are the intellectual property of Analog Devices or its licensors. While you may use the "Circuits from the Lab" in the design of your product, no other license is granted by implication or otherwise under any patents or other intellectual property by application or use of the "Circuits from the Lab". Information furnished by Analog Devices is believed to be accurate and reliable. However, "Circuits from the Lab" are supplied "as is" and without warranties of any kind, express, implied, or statutory including, but not limited to, any implied warranty of merchantability, noninfringement or fitness for a particular purpose and no responsibility is assumed by Analog Devices for their use, nor for any infringements of patents or other rights of third parties that may result from their use. Analog Devices reserves the right to change any "Circuits from the Lab" at any time without notice, but is under no obligation to do so. Trademarks and registered trademarks are the property of their respective owners. ©2010 Analo 图 2和图 3显示，本电路在 25°C环境温度时的电流输出精度 和电压输出精度典型值分别为 0.016%和 0.012%。 本电路必须构建在具有较大面积接地层的多层电路板上。为 实现最佳性能，必须采用适当的布局、接地和去耦技术（请 参考教程MT-031—“实现数据转换器的接地并解开AGND和 DGND的迷团”，以及教程MT-101—“去耦技术”）。 图 2.电流输出精度 图 3.电压输出精度 进一步阅读 Kester, Walt. 2005. The Data Conversion Handbook. Analog Devices. Chapters 3 and 7. MT-015 Tutorial, Basic DAC Architectures II: Binary DACs. Analog Devices. MT-031 Tutorial, Grounding Data Converters and Solving the Mystery of AGND and DGND. Analog Devices. MT-101 Tutorial, Decoupling Techniques. Analog Devices. Voltage Reference Wizard Design Tool. 数据手册和评估板 AD5422 Data Sheet. AD5422 Evaluation Board. 修订历史 7/09—Revision 0: Initial Version g Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. CN08285-0-7/09(0) w w w . a n a l o g . c o m Rev. 0 | Page 2 of 2