Click here for production status of specific part numbers. Evaluates: MAX5992A MAX5992A Evaluation Kit MAX5992B General Description Features The MAX5992A/B evaluation kit (EV kit) is a fully assem- IEEE 802.3af/at-Compliant PD Interface Circuit bled and tested surface-mount circuit board featuring -39V to -57V Startup Input Voltage Range the MAX5992A/B IEEE 802.3af/at-compliant network Active FET Bridge powered device (PD) interface controller IC, which pro vides PD detection signature, PD classification signature, Demonstrates 2x2P PD and Multi-PD Redundancy inrush current control, undervoltage lockout (UVLO), Configurations and active FET-bridge driver. The EV kit is a compact Demonstrates an Isolated 100W Active-Clamped, and low-cost design used in power-over-Ethernet (PoE) Synchronous-Rectified Forward DC-DC Converter applications requiring DC power from an Ethernet Isolated +12V Output at 8.4A network port for PDs, such as fiber-to-the-femotocell/ picocell/microcell, fiber-to-the-home/fiber-to-the-building PD Detection and Configurable Classification (FTTH/FTTB), IP phones, wireless access nodes, and Signatures security cameras. Internal UVLO at +38.6V The EV kit features a 2x2P PD or multi-PD redundancy Evaluates End Span and Midspan Ethernet Systems configuration using the ICs. The 2x2P powers a galvani - Proven PCB Layout cally isolated 100W, 250kHz switching-frequency, active- Fully Assembled and Tested clamped, synchronous-rectified forward DC-DC converter using the MAX5974D. The device circuit achieves high efficiency by using a forward DC-DC converter topology. The surface-mount transformer provides up to +1500V Ordering Information appears at end of data sheet. galvanic isolation for the output. The EV kit output voltage is configured for +12V and provides up to 8.4A load current. Note: In the multi-PD redundancy mode, the total output power must be reduced to 50W, which is limited by the LAN transformer on board. Its port current must be limited to 1.2A per 2 pair. The EV kit circuit receives its power from IEEE 802.3af/ at-compliant power-sourcing equipment (PSE). The PSE provides the required -44V to -57V DC power over a twisted-pair Ethernet network cable to the EV kits RJ45 connectors. The EV kit features an active FET bridge for separating the DC power provided by an end-span or mid-span Ethernet system. Warning: The EV kit is designed to operate with high voltages. Dangerous voltages are present on this EV kit and on equipment connected to it. Users who power up this EV kit, or power the sources connected to it, must be careful to follow safety procedures appropriately to work with high-voltage electrical equipment. Under severe fault or failure conditions, this EV kit may dissipate large amounts of power, which could result in the mechanical ejection of a component or of component debris at high velocity. Operate this kit with care to avoid possible personal injury. 319-100383 Rev 1 6/19MAX5992A Evaluation Kit Evaluates: MAX5992A MAX5992B The EV kit is a 2x2P PD configuration PoE using the Quick Start PD controller IC. The 2x2P PD interface powers a Required Equipment galvanically isolated 100W DC-DC converter using the MAX5992A/B EV kit MAX5974D active-clamped, current-mode PWM controller IC in a forward-feedback topology. The EV kit receives MAX5980 EV kit power from two IEEE 802.3af/at-compliant PSEs and two IEEE 802.3af/at-compliant PSE and Category 5e UTP cables connected to the EV kits RJ45 connectors. Ethernet network cable The EV kit accepts power from an endspan or midspan Two -54V, 15A-capable DC power supply PSE network con figuration. The EV kit also provides Ethernet jacks J1 DATA and J2 DATA for interfacing to Voltmeter the Ethernet data signals. PCB pads -54V1, -54V2, and Procedure GND are available for powering the EV kit, if network The EV kit is fully assembled and tested. Follow the steps connectivity is not required. below to verify board operation. Caution: Do not turn on The EV kit output voltage is configured for +12V and the power supply until all connections are completed. provides up to 8.4A output current. The EV kit circuit use 1) Use one of the following methods to power the EV kit: MOSFETs N1 and N2 for synchronous rectification on the a) If network connectivity is required: Connect a secondary side. Transformer T1 provides up to 1500V Category 5e ethernet network cable from the EV galvanic isolation for the output. Isolated feedback voltage kit input ports RJ45 connectors (J1 POWER, is achieved using optocoupler U4 and voltage reference J2 POWER) to the corresponding PSE ethernet U5. Current-sense resistors R45 and R46 limit the peak LAN connections, which provide power to the current through transistor N7 and primary transformer T1. EV kit. Two modular RJ45 jacks (J1 DATA, Capacitor C14 and transistor N12 form a clamping J2 DATA) provide an interface with the ethernet net-work that protects transformer T1 against saturation data signals only. due to reverse current, by monitoring the voltage across the MAX5974Ds CS input during auxiliary driver N4 off-time. b) If network connectivity is not required: Connect a -54V DC power supply between the The EV kit accommodates mainly two applications to -54V1, -V54V2, and GND PCB pads on the EV exercise: 2x2P and multi-PD redundancy. As a default, kit. Connect the power-supply positive terminal the EV kit is set to 2x2P. Besides these two configurations, to the V+ PCB pad and the negative terminal to single PD operation can be configured, but power is the V- PCB pad. limited by the current capability of the LAN transformer, which supports up to 1.2A per 2P. 2) Activate the PSE power supply or turn on the external DC power supply. In the 2x2P application, there are sets of PoE power lines. 3) Using a voltmeter, verify that the EV kit provides Each PSE has its own PD. The PSEs are all connected to +12V across the V and RTN PCB pads. OUT the same power supply. The two PoE sets share the same Ethernet cable. Figure 1 is the system-level diagram. To Detailed Description of Hardware test the EV kit in 2x2P, the MAX5980A EV kit needs to (or Software) reconfigured into 2x2P mode accordingly. Refer to the The MAX5992A/B EV kit is a fully assembled and tested MAX5980 EV kit data sheet for more details. surface-mount circuit board that evaluates the MAX5992A/B In multi-PD redundancy mode, the PSEs are independent. IEEE 802.3af/at-compliant network PD interface controller. The input voltages of each PSE can be different. Each The EV kit features two powered Ethernet ports, two data- PSE is connected to its PD through an independent only Ethernet ports, and a MAX5974D active-clamped, ethernet cable (see Figure 1). current-mode PWM controller IC. Maxim Integrated 2 www.maximintegrated.com