原标题：ADI ADuM347x四路带PWM控制和变压器驱动数字隔离方案

　　ADI公司的ADuM347x是四路带PWM控制和变压器驱动数字隔离器，采用ADI的iCoupler技术，器件的DC/DC转换器提供高达2W的输出，5.0V或3.3V输入输出电压从3.3V到24V, 200 kHz 到1 MHz可调频率，主要用在RS-232/RS-422/RS-485收发器，工业现存总线隔离，绝缘传感器接口和过程控制等.本文介绍了ADuM347x主要特性，功能方框图，I/O通路框图以及单电源与正和不稳压负电源的应用电路图，所用变压器参考设计.

　　The ADuM347xdevices are quad-channel, digital isolators with an integrated PWM controller and transformer driver for an isolated dc-to-dc converter. Based on the Analog Devices, Inc., iCoupler technology, the dc-to-dc converter provides up to 2 W of regulated, isolated power at 3.3 V to 24 V from a 5.0 V input supply or from a 3.3 V supply. This eliminates the need for a separate, isolated dc-to-dc converter in 2 W isolated designs.

　　The iCoupler chip-scale transformer technology is used to isolate the logic signals, and the integrated transformer driver with isolated secondary side control provides higher efficiency for the isolated dc-to-dc converter. The result is a small form factor, total isolation solution.

　　The ADuM347x isolators provide four independent isolation channels in a variety of channel configurations and data rates.

　　ADuM347x主要特性：

　　Isolated PWM Controller

　　Integrated transformer driver

　　Regulated adjustable output: 3.3 V to 24 V

　　2 W output power

　　70% efficiency at guaranteed load of 400 mA at 5.0 V output

　　Quad dc-to-25 Mbps (NRZ) signal isolation channels

　　20-lead SSOP package

　　High temperature operation: 105℃

　　High common-mode transient immunity: >25 kV/μs

　　200 kHz to 1 MHz adjustable oscillator frequency

　　Soft start function at power-up

　　Pulse-by-pulse overcurrent protection

　　Thermal shutdown

　　2500 V rms isolation

　　ADuM347x 应用：

　　RS-232/RS-422/RS-485 transceivers

　　Industrial field bus isolation

　　Power supply startup bias and gate drives

　　Isolated sensor interfaces

　　Process controls

　　图1.ADuM347x功能方框图

　　图2.ADuM347x I/O通路框图

　　图3.ADuM347x单电源应用电路图

　　图4.ADuM347x正和不稳压负电源应用电路图

　　变压器参考设计