The MAX5952A evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board featuring an Ethernet four-port power-sourcing equipment (PSE) circuit for -48V supply rail systems. The IEEE 802.3af and pre-802.3at-compliant MAX5952A PSE controller in a 36-pin SSOP package and four n-channel power MOSFETs are used to form the main power-sourcing equipment circuit on the EV kit. The MAX5952A 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-compliant 3-wire interface. The isolated interface can connect to a PC's USB port through a CMAXQUSB interface board. 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 capable of supplying 100mA for the EV kit's +3.3V optically isolated 3-wire interface.
The MAX5952A EV kit requires a -32V to -60V power supply (-48V supply rail) capable of supplying 4A or more to the EV kit for the power device (PD) through the four 10/100BASE-TX Ethernet network ports. The EV kit demonstrates PD discovery, classification, current-limit control, and other functions of an IEEE 802.3af and pre-802.3at-compliant PSE.
The MAX5952A controls the -48V DC power to each of the four Ethernet network ports by controlling the port's power MOSFET and sensing current through the respective port's current-sense resistor. The current is fed to a 10/100BASE-TX voice-over-IP magnetic module at each Ethernet output port. The MAX5952A 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 MAX5952A for each power channel such as configurable operational modes, high-power modes (programmable for up to 45W per port), port current information through I²C interface, PD detection, PD classification, overcurrent protection, current foldback, under/overvoltage protection and AC-disconnect monitoring. All these features are configurable on the EV kit and additional test points for voltage probing and current measurements have been provided.
The EV kit software is Windows® 98SE/2000/XP compatible and provides a user-friendly interface to demonstrate the features of the MAX5952A while also providing access to each register at the bit level. The program is menu driven and offers a graphic interface with control buttons. The program also includes a macro engine to allow automated evaluation and testing of the MAX5952A at the system level. The program's macro output files can be automatically saved.
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