Simplified Block Diagram
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- IEEE 802.3af/at-Compliant PSE Circuit
- High-Power Mode (Programmable Up to 30W per Port or Up to 60W in a 2 x 2 Pair Configuration)
- Port Current Readout Through the I²C Interface
- Input Voltages
- -32V to -60V Providing 4A (-48V/-54V Power Circuit, 1A/Port)
- Ethernet Network Ports
- Four RJ45 10/100/1000BASE-TX Ethernet Network Input Ports
- Four RJ45 10/100/1000BASE-TX Ethernet Network Output PoE Ports
- Demonstrates Four Separate Independent Power Switch Controllers
- Demonstrates PD Detection and Classification
- DC Load Removal Detection and Disconnect Monitoring
- Convenient Voltage and Current Test Points
- Four Output-Port LED Status Indicators
- Optically Isolated I²C-Compatible 3-Wire PC Interface
- Reconfigurable for Stand-Alone Operation or with an External Microcontroller (Requires a +3.3V, 100mA Supply)
- Windows XP-, Windows Vista-, and Windows 7-Compatible Software
- Proven PCB Layout
- Fully Assembled and Tested
- Midspan Power Injectors
- Power-Sourcing Equipment (PSE)
The MAX5980 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board featuring an Ethernet 4-port power-sourcing equipment (PSE) circuit for -48V or -54V supply rail systems. The IEEE® 802.3af/at-compliant MAX5980 PSE controller, in a 32-pin TQFN-EP package, and four n-channel power MOSFETs are used to form the main PSE circuit on the EV kit. The IC is used in Power-over-Ethernet (PoE) applications requiring DC power over four Ethernet network ports. The EV kit provides optical isolation for the I²C-compatible 3-wire interface. The isolated interface can connect to a PC's USB port through an on-board USB interface circuit. The EV kit can easily be reconfigured for interfacing to a user's stand-alone microcontroller for isolated or nonisolated operation. In stand-alone operation, the user must supply a separate 3.3V power supply (with respect to VEE) capable of supplying 100mA for the EV kit's +3.3V optically isolated 3-wire interface.
The EV kit requires a -32V to -60V power supply (-48V/-54V supply rail) capable of supplying 4A or more to the EV kit for powering the powered device (PD) through the four 10/100/1000BASE-TX Ethernet network ports. The EV kit demonstrates PD discovery, classification, current-limit control, and other functions of an IEEE 802.3af/at-compliant PSE circuit.
The IC controls the -48V/-54V DC power to each of the four Ethernet network ports by controlling the ports' power MOSFET and sensing current through the respective port's current-sense resistor. The current is fed to a 10/100/1000BASE-TX magnetic module at each Ethernet output port. The EV kit provides a separate, independent power channel for each of the four Ethernet output ports.
The EV kit demonstrates the full functionality of the IC for each power channel, such as configurable operational modes, high-power mode (programmable up to 30W per port or up to 60W in a 2 x 2 pair configuration), port current information through the I²C interface, PD detection, PD classification, overcurrent protection, current foldback, under/overvoltage protection, and DC disconnect monitoring. All these features are configurable on the EV kit. Additional test points for voltage probing and current measurements have also been provided.
The EV kit includes Windows XP®-, Windows Vista®-, and Windows® 7-compatible software and provides a user-friendly interface to demonstrate the features of the IC, while also providing access to each register at the bit level. The program is menu-driven and offers a graphical user interface (GUI) with control buttons. The program also includes a macro engine to allow automated evaluation and testing of the IC at the system level. The program's macro output files can be automatically saved.