MAX5988DETP+

Power Over Ethernet (PoE) Controllers

Power Over Ethernet (PoE) Controllers is a technology that allows an electrical device to receive power and data over the same cable. This technology has become increasingly popular in applications such as IP cameras and wireless access points, where the ability to both power and communicate over the same cable provides an ideal solution for installations where the power outlets are not immediately available. The MAX5988DETP+ is a PoE controller that is specifically designed for PoE applications.

MAX5988DETP+ Application Field

The MAX5988DETP+ is a high-efficiency, low-voltage CMOS-compatible controller that enables PoE applications and offers various features, providing a simple and effective solution for powering remote devices with power and data over the same cable. Its features and advantages make the MAX5988DETP+ suitable for a wide range of PoE applications, including Power over Ethernet (PoE) switches, routers, gateways, IP surveillance cameras, and distance-extended applications.

The device functions as a bridge between an Ethernet port and a switching power supply and is capable of detecting and collecting power from the remote phone lines, providing up to 15 to 25W of power depending on the user’s preference. The 1×1mm 24-pin LLP package enables easy PCB routing and excellent thermal characteristics in a small form factor. The power output can be adjusted depending on the system requirements, and the sequencing can also be customized. With wide common-mode range of ±18V, it can handle most Ethernet cable noise.

MAX5988DETP+ Working Principle

The MAX5988DETP+ controller is an integrated solution for PoE applications, consisting of I2C EEPROM, power control and management, and LED control. It works in two modes – active and link. In active mode, the controller detects and powers up PDs (powered devices) and delivers power up to 25W. In link mode, the controller performs link status monitoring for network synchronization. It also switches between active and link modes and provides fault protection.

The MAX5988DETP+ starts by detecting PoE PDs using the standby power current level (PSE) in Class 0, Class 1, and Class 2. After the PD is detected and identified, the controller will turn on the main power, the PD power supply, and charge the capacitor. When the PD voltage is above the maximum voltage threshold, the controller will switch to the link mode and send power to the PD. During the link mode, the controller monitors the transmitter link status and checks for any short circuit violation or power loss.

In the event of a short circuit violation or power loss, the controller will switch to standby mode, disable the PSE, and reset the PD. During the fault condition, the device can be reset by the user or by a scheduler. In the normal operation, the PSE is disabled and power is held until the user changes the configuration or disables the PSE.

Conclusion

The MAX5988DETP+ is a powerful, versatile, and cost-effective PoE controller that provides a simple, reliable solution for powering remote devices over Ethernet connections. With its wide common-mode range of ±18V, it can handle most Ethernet cable noise, providing up to 15 to 25W of power depending on the system requirements. In addition to providing power, it also monitors for link status and provides fault protection in the event of a short circuit violation or power loss.