Maxim MAX5969A IEEE 802.3af-at兼容以太网供电方案

Maxim 公司的MAX5969A/MAX5969B是和POE系统的 IEEE 802.3af/at标准兼容的以太网供电完整接口,具有检测和分类信号,并集成了瞬态输入浪涌电流控制的绝缘功率开关,工作时电流在720mA和880mA之间,最大输入电压100V,主要应用IEEE 802.3af/at受电设备, IP电话,无线接入点,IP安全照相机和WiMAX基站.本文介绍MAX5969A/B主要特性,方框图, 典型工作电路图和应用电路图.

IEEE 802.3af/at-Compliant, Powered Device Interface Controllers with Integrated Power MOSFET

The MAX5969A/MAX5969B provide a complete interface for a powered device (PD) to comply with the IEEE® 802.3af/at standard in a power-over-Ethernet (PoE) sys­tem. The MAX5969A/MAX5969B provide the PD with a detection signature, classification signature, and an inte­grated isolation power switch with inrush current control. During the inrush period, the MAX5969A/MAX5969B limit the current to less than 180mA before switching to the higher current limit (720mA to 880mA) when the isolation power MOSFET is fully enhanced. The devices feature an input UVLO with wide hysteresis and long deglitch time to compensate for twisted-pair cable resistive drop and to assure glitch-free transition during power-on/-off conditions. The MAX5969A/MAX5969B can withstand up to 100V at the input.
..

查看全文