Monolithic Power Systems Inc. EV3908DK-00C

Overview

EV3908DK-00C from Monolithic Power Systems is an evaluation board for the MP3908DK synchronous flyback controller IC, configured as a fully assembled, isolated 3.3V/7.5A (25W) DC-DC converter operating from 36–72V input. It implements current-mode control, 250kHz fixed-frequency operation, and features a synchronous rectification gate drive to replace Schottky diodes with MOSFETs for high efficiency.

For engineers reviewing the EV3908DK-00C datasheet, EV3908DK-00C pinout, EV3908DK-00C application, or EV3908DK-00C equivalent, this board enables rapid validation of MP3908DK-based isolated flyback designs in PoE-powered systems, telecom brick modules, and CCFL backlight supplies - with verified thermal performance, load regulation, and enable-controlled startup sequencing.

Technical Context

The EV3908DK-00C implements a transformer-isolated flyback topology using the MP3908DK controller (MSOP-10), which integrates a high-side gate driver for synchronous rectification on the secondary side. It supports cycle-by-cycle current limiting and under-voltage lockout at 32V (typical).

Input voltage range is strictly 36–72V DC; output is factory-set to 3.3V ±1% at full load, adjustable via feedback resistor network (R5, R19). Efficiency peaks at 94% (VIN=48V, IO=5A) and remains ≥85% across 1–7.5A load range per published curves.

Key Specifications

Availability

EV3908DK-00C is available at Aetrix Electronics and suitable for Power over Ethernet (PoE) injectors, telecom isolated DC-DC bricks, and CCFL backlight inverters requiring stable component supply, pre-validated thermal layout, and production-ready reference schematics.

Supply support for EV3908DK-00C 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 analog semiconductor company specializing in high-performance power management ICs, with core expertise in DC-DC conversion, LED drivers, and motor control solutions.

The MP3908DK product line targets high-efficiency isolated flyback applications where synchronous rectification, wide input range, and minimal external components are critical - especially in space-constrained PoE and telecom infrastructure.

FAQ

What input voltage range does the EV3908DK-00C support?

The board accepts 36–72V DC input, aligned with standard telecom (-48V nominal) and IEEE 802.3bt Type 4 PoE++ power sourcing equipment. Operation below 36V triggers UVLO shutdown; above 72V exceeds absolute maximum rating and risks damage to T1 transformer and input capacitors.

Can the output voltage be adjusted, and how?

Yes - output is set by the R5 (2.49kΩ) and R19 (3.01kΩ) resistor divider on the feedback network. Replacing either resistor changes the VOUT according to VOUT = 1.24 × (1 + R5/R19). The board includes test points for safe probing during adjustment.

Does the board include synchronous rectification, and how is it implemented?

Yes - the MP3908DK drives Q5 (Si4166DY, SO-8 N-channel MOSFET) as the synchronous rectifier on the secondary side, replacing a Schottky diode. Gate timing is internally optimized to minimize shoot-through and conduction loss, contributing to >90% efficiency at mid-load.

What isolation voltage is certified, and what component provides it?

The board achieves 3 kV RMS isolation between primary and secondary circuits, provided by the Cooper CTX01-18290-R planar transformer (Pri:Sec:Aux = 8:1:4, Lm = 120µH). Creepage and clearance meet IEC 60950-1 requirements for reinforced insulation.

How is enable/disable functionality controlled?

The EN pin (U1 Pin 1) accepts a logic-level signal: <2V enables regulation; >2V disables switching and reduces quiescent current to 10µA. No external pull-up is required - internal bias ensures default-enable behavior when left floating.

Is thermal performance documented, and what is the max ambient temperature?

Published efficiency vs. load curves (Fig. 1, Rev. 1.0) confirm stable operation up to 70°C ambient with natural convection cooling. Board layout uses 2oz copper, thermal vias under Q2/Q5, and exposed pads on U1 and Q5 - no heatsink required at ≤7.5A output.