Monolithic Power Systems Inc. EV3908+8002+6901-00A

Overview

EV3908+8002+6901-00A from Monolithic Power Systems is an IEEE 802.3at-compliant Powered Device (PD) evaluation board integrating MP3908DK (PWM controller), MP8002DN (PD interface IC), and MP6901DS (synchronous rectifier controller). It delivers 5 V / 0–6 A output from 40–57 V PoE input, supports detection/classification, inrush current limiting, thermal protection, and power-good signaling. Designed for rapid validation of PoE-powered systems including VoIP phones and security cameras.

For engineers reviewing the EV3908+8002+6901-00A datasheet, EV3908+8002+6901-00A pinout, EV3908+8002+6901-00A application, or EV3908+8002+6901-00A equivalent, this board provides a complete, tested reference design for IEEE 802.3at Class 4 PD implementation with integrated DC/DC control and synchronous rectification.

Technical Context

The board implements a flyback topology with primary-side regulation via MP3908DK, featuring 250 kHz fixed-frequency current-mode control, soft-start, slope compensation, and peak current limiting. MP8002DN handles IEEE 802.3at detection (25 kΩ signature), classification (Class 4), programmable inrush limit, and open-drain power-good output.

MP6901DS drives synchronous rectification on the secondary side to improve efficiency, while external components include a Würth LAN transformer (749020011), Cooper power-stage transformer (CTX01-18290), and dual RJ-45 jacks (J1/J2) supporting both data and power injection paths.

Key Specifications

Availability

EV3908+8002+6901-00A is available at Aetrix Electronics and suitable for VoIP telephony, IP security camera deployment, and industrial remote power applications requiring stable component supply and pre-validated IEEE 802.3at compliance.

Supply support for EV3908+8002+6901-00A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with core expertise in DC/DC conversion, LED drivers, and PoE solutions.

This evaluation board belongs to MPS's IEEE 802.3at PD reference design portfolio, developed to accelerate customer adoption of high-power PoE infrastructure by providing fully tested, schematically documented hardware with production-grade component selection.

FAQ

What is the maximum power delivery capability of the EV3908+8002+6901-00A board?

The board delivers up to 30 W (5 V × 6 A) continuously, compliant with IEEE 802.3at Class 4 specifications. This is achieved using a flyback converter with MP3908DK primary control and MP6901DS-driven synchronous rectification on the secondary side, minimizing conduction losses.

Does the board support both Mode A and Mode B power injection?

Yes - the board accepts power via standard Ethernet cabling using either Mode A (pins 1/2 and 3/6) or Mode B (pins 4/5 and 7/8), enabled by dual RJ-45 jacks J1 and J2 with integrated signal-line EMI filters and full bridge rectification (CR1/CR2).

Can the EV3908+8002+6901-00A be powered from a non-PoE DC source?

Yes - the board accepts 40–57 V DC directly via VDD/VSS terminals, bypassing the Ethernet jack. This allows lab validation without a PSE and supports hybrid power architectures where PoE serves as backup and DC input as primary.

Which ICs are mounted on the board and what are their roles?

The board integrates MP3908DK (primary-side PWM controller with soft-start and current-mode control), MP8002DN (PoE PD interface with 25 kΩ detection, Class 4 classification, and power-good signaling), and MP6901DS (secondary-side synchronous rectifier driver optimizing efficiency above 85% at full load).

Is thermal protection implemented, and how does it behave under overload?

Yes - MP8002DN includes temperature-compensated current limiting and thermal shutdown. Under sustained overload, the device reduces output current progressively and latches off if junction temperature exceeds safe threshold, protecting both IC and external MOSFETs (Q2–Q4).

What external components are required to operate the board?

No external components are required - the board includes all critical elements: Würth LAN transformer (749020011), Cooper power transformer (CTX01-18290), dual RJ-45 jacks, input/output capacitors, and discrete MOSFETs (Si7450, Si4840, 2N7002). Only a load and PSE or DC supply are needed for operation.