Simplified Block Diagram
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- IEEE 802.3af/at-Compliant PD Interface Circuit
- -30V to -57V Input Range
- Demonstrates an Isolated +12V/22.7W Flyback DC-DC Converter
- PD Detection and Configurable Classification Signatures
- 2-Event Classification or Wall Adapter Detect Output
- Power-Good Indicator Output
- In-Rush Current Limit of 180mA (max)
- Evaluates Endspan and Midspan Ethernet Systems
- Evaluates the MAX5969B/MAX5969A in a 10-Pin TDFN Package
- Simplified Wall Adapter Interface
- Fully Assembled and Tested
- IEEE 802.3af/at Powered Devices
- IP Phones, Wireless Access Nodes, IP Security Cameras
- WiMAX™ Base Station
The EV kit receives power from IEEE 802.3af/at-compliant power-sourcing equipment (PSE). Refer to the MAX5965 and MAX5971 IC data sheets for PSE controllers. The PSE provides the required -30V to -57V DC power over an unshielded twisted-pair Ethernet network cable to the EV kit's RJ45 magnetic jack. The EV kit features a 1 x 1GbE RJ45 magnetic jack and two diode bridges for separating the DC power provided by an endspan or midspan Ethernet system.
The EV kit can also be powered by a wall adapter power source. The EV kit provides PCB pads to accept the output of a wall adapter power source. When a wall adapter power source is detected, it always takes precedence over the PSE source, allowing the wall adapter to power the EV kit.
The EV kit demonstrates the full functionality of the IC, such as PD detection signature, PD classification signature, in-rush current control, and input undervoltage lockout (UVLO). The EV kit also provides a modular RJ45 jack to interface with the Ethernet data signals only.
The EV kit also features a galvanically isolated 22.7W, 600kHz switching frequency flyback DC-DC converter, which uses the MAX15000A current-mode PWM controller. The IC's output provides power for the converter circuit. The DC-DC converter is configured for an output voltage of +12V and provides up to 1.9A. High efficiency up to 89% is achieved using a single transistor flyback DC-DC converter topology. The surface-mount transformer provides up to +1500V galvanic isolation for the output. UVLO, soft-start, and thermal shutdown provide a robust 22.7W isolated power supply. The DC-DC converter operates at 600kHz, allowing the use of small magnetics and output capacitors. The EV kit can also evaluate the MAX5969A after IC replacement (U1).