Monolithic Power Systems Inc. EVM3686-RU-00A

Overview

EVM3686-RU-00A from Monolithic Power Systems is an evaluation board for the MPM3686GRU 20A step-down power module, designed to demonstrate high-efficiency DC/DC conversion in telecom and server applications. It supports input voltages from 8–18V, delivers adjustable output voltages (1.0/1.2/1.5/1.8V), sustains 20A continuous load, features adaptive COT control, and integrates thermal shutdown and non-latch OCP/OVP.

For engineers reviewing the EVM3686-RU-00A datasheet, EVM3686-RU-00A pinout, EVM3686-RU-00A application, or EVM3686-RU-00A equivalent, this board enables rapid validation of MPM3686GRU's transient response, efficiency across light-to-full load, pre-bias startup behavior, soft-start timing, and protection sequencing under real-world thermal and layout constraints.

Technical Context

The EVM3686-RU-00A implements a complete reference design for the MPM3686GRU - a fully integrated 18V/20A buck power module with internal MOSFETs and power inductor in a 12×15×4mm QFN package. It uses constant-on-time (COT) control with adaptive frequency scaling to maintain >90% efficiency from 10% to 100% load at 12V_IN/1.2V_OUT.

Board-level features include jumper-selectable V_OUT (1.0/1.2/1.5/1.8V), external bias support for 2.5V–18V operation, programmable soft-start (default 3ms), and non-latching fault protections: over-current, over-voltage, under-voltage lockout, and thermal shutdown.

Key Specifications

Availability

EVM3686-RU-00A is available at Aetrix Electronics and suitable for telecom base station power validation, server VR13-compliant core rail testing, flat-panel display logic supply characterization, and distributed power system architecture prototyping requiring stable component supply and documented thermal performance.

Supply support for EVM3686-RU-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 design centers in the US, China, Korea, and Taiwan, and global manufacturing partnerships.

The MPM3686 product line delivers fully integrated, high-current DC/DC power modules targeting space-constrained, thermally demanding applications in networking infrastructure and computing systems where layout simplicity and reliability are critical.

FAQ

What is the primary purpose of the EVM3686-RU-00A?

The EVM3686-RU-00A is a functional evaluation board built around the MPM3686GRU power module. It enables engineers to verify electrical performance-including efficiency, transient response, startup behavior, and protection activation-under real PCB thermal and layout conditions before integrating into final systems.

Can the EVM3686-RU-00A operate below 8V input?

Yes - the default 8V minimum input is set by the EN pin resistor divider. By adjusting R1/R2 values per the MPM3686 datasheet, the board supports input as low as 4.5V when using internal bias or 2.5V with an external 5V bias supply, maintaining full 20A capability.

How is output voltage selected on this board?

V_OUT is set via a 2-pin jumper (J1) that selects between four fixed feedback resistor networks. Positions correspond to 1.0V, 1.2V, 1.5V, or 1.8V - no soldering or external components are needed for these standard logic rail voltages.

Is the EVM3686-RU-00A RoHS compliant and lead-free?

Yes - all components on the EVM3686-RU-00A, including the MPM3686GRU module and passive parts, are lead-free and comply with the EU RoHS Directive. MPS confirms green status for this part family on its Quality Assurance portal.

Why is this board marked "NOT RECOMMENDED FOR NEW DESIGNS"?

MPS has superseded the EVM3686-RU-00A with the EVM3695-25-RF-02A, which evaluates the newer MPM3695 - offering improved efficiency at light load, tighter output voltage accuracy (±0.5%), and enhanced thermal derating above 70°C ambient.

Does the board support pre-bias start-up?

Yes - the MPM3686GRU IC on this board supports pre-bias start-up, allowing the output capacitor to retain residual voltage during hot-swap or multi-rail sequencing. The evaluation board preserves this function without modification to enable realistic system-level testing.