Monolithic Power Systems Inc. EVQ28261-L-00A

Overview

EVQ28261-L-00A from Monolithic Power Systems is an evaluation board for the MPQ28261DL synchronous step-down converter, designed to demonstrate 1.2V/3A power delivery from a 7–21V input with fixed 500kHz switching, internal MOSFETs, and thermal/OCP protection in a QFN3x4-14 package.

For engineers reviewing the EVQ28261-L-00A datasheet, EVQ28261-L-00A pinout, EVQ28261-L-00A application, or EVQ28261-L-00A equivalent, this board enables rapid validation of MPQ28261DL performance under load transients, efficiency testing at VIN = 12V/21V, and soft-start behavior using external RC networks on SS and FB pins.

Technical Context

The EVQ28261-L-00A implements a current-mode control architecture with fixed 500kHz frequency, enabling fast transient response and stable loop compensation using only two external resistors (R1/R2) for feedback and one RC network (R3/C3) for soft-start. It supports 1.2V output regulation with ±2% accuracy via a 0.6V internal reference.

Board-level design integrates a 2.2μH power inductor (Wurth 744311220), dual 22μF ceramic output capacitors (C2A/C2B), and 15pF feedforward capacitor (C6) to optimize phase margin and reduce output ripple below 10mVpp at 3A load.

Key Specifications

Availability

EVQ28261-L-00A is available at Aetrix Electronics and suitable for DSL modems, cable modems, set-top boxes, and FPGA power sequencing requiring stable component supply and validated reference designs.

Supply support for EVQ28261-L-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 expertise in DC/DC conversion, LED drivers, and motor control.

The MPQ28261 product line targets space-constrained, high-efficiency point-of-load applications in broadband infrastructure, delivering integrated 3A buck regulation in thermally enhanced QFN packages.

FAQ

What input voltage range is supported by the EVQ28261-L-00A evaluation board?

The board operates across 7V to 21V input, verified per MPQ28261DL specifications. Test data shows stable 1.2V output regulation and >90% efficiency at both 12V and 21V inputs with 3A load, confirming robustness over full specified range.

How is output voltage set on this evaluation board?

VOUT is fixed at 1.2V using a resistor divider (R1 = 10kΩ, R2 = 10kΩ) from FB to GND, leveraging the MPQ28261DL's 0.6V internal reference. No trimming is required; the ratio yields exactly 1.2V with ±2% tolerance as confirmed in test reports.

Does the board include thermal protection validation?

Yes - thermal shutdown is implemented via the MPQ28261DL's internal sensor. Board-level testing confirms automatic shutdown at ~125°C junction temperature and full recovery within 100ms after cooling, with no latch-up observed during repeated cycles.

Can the switching frequency be adjusted?

No - the MPQ28261DL uses a fixed 500kHz oscillator. The EVQ28261-L-00A does not provide frequency modulation options; all timing components (including BST capacitor C2C) are selected to meet this fixed-frequency requirement per datasheet layout guidelines.

What is the purpose of the 15pF capacitor (C6) on the FB node?

C6 is a feedforward capacitor placed directly across the upper feedback resistor (R1). It improves phase margin and transient response by injecting high-frequency signal into the error amplifier, reducing output voltage overshoot during load steps - validated in waveform tests on page 4 of the rev.1.0 document.

Is the EN pin functional on this evaluation board?

Yes - EN is routed to a test point and accepts TTL-compatible logic: ≥1.6V enables regulation, ≤0.4V disables it with full UVLO and bias shutdown. Quick Start Guide section 5 confirms digital control capability without additional level-shifting circuitry.