Monolithic Power Systems Inc. EV5403-QB-02A

Overview

EV5403-QB-02A from Monolithic Power Systems is an evaluation board designed to demonstrate the MP5403 power management IC, which integrates two high-efficiency buck converters (3.5A/2.5A) and one 3A load switch with 20mΩ R_ON, operating from 2.7–6V input and delivering fixed 1.2V/1.2V outputs for SSD and portable instrument power rails.

For engineers reviewing the EV5403-QB-02A datasheet, EV5403-QB-02A pinout, EV5403-QB-02A application, or EV5403-QB-02A equivalent, this board enables rapid validation of MP5403's dual-buck + load-switch functionality, thermal performance under 25°C ambient, soft-start behavior, and PG signal timing in compact power systems.

Technical Context

The EV5403-QB-02A implements the MP5403 IC in a QFN20 (2.5mm × 3mm) package with externally set feedback resistors (R1A/R2A, R1B/R2B) establishing 1.2V outputs, and includes discrete 1μH inductors (L1/L2), 22μF ceramic output capacitors (C4A/C4B/C5A/C5B), and 100kΩ enable-pullup resistors (R3/R5–R11) for automatic startup.

It supports independent enable control (EN1/EN2/EN3), three power-good indicators (PG1/PG2/PG3), PFL_ADJ for input power-fail threshold tuning, and V_SUS for suspend-mode control - all accessible via test points and header pins on the 6.5cm × 6.5cm PCB.

Key Specifications

Availability

EV5403-QB-02A is available at Aetrix Electronics and suitable for Solid-State Drive reference design validation, portable instrument power subsystem characterization, and battery-powered device PMIC integration requiring stable component supply and documented test waveforms.

Supply support for EV5403-QB-02A 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 over two decades of innovation in DC/DC conversion, motor drivers, and power management solutions.

The MP5403 product line targets space-constrained, high-current digital power rails - specifically engineered for ASIC/SOC core and I/O voltage regulation in SSDs and ultra-portable electronics where low R_ON, low IQ, and small footprint are critical.

FAQ

Is EV5403-QB-02A recommended for new designs?

No. The board is explicitly marked "NOT RECOMMENDED FOR NEW DESIGNS" per its revision 1.0 documentation. It remains valid for legacy MP5403 evaluation and failure analysis but should not be selected for production-intent hardware development or qualification.

What is the role of the PFL_ADJ pin on the EV5403-QB-02A board?

PFL_ADJ (Pin 2 of U1) sets the input power-fail detection threshold for the PFL signal. On this board, it connects to a resistor divider (R3/R4) enabling adjustable VIN1 undervoltage lockout with user-defined delay via C_DELAY, as specified in the MP5403 datasheet.

Can VOUT1 and VOUT2 be adjusted independently on this evaluation board?

Yes. VOUT1 is set by R1A/R2A and VOUT2 by R1B/R2B, each forming a separate resistive divider from FB1/FB2 to GND. The Quick Start Guide provides the formula V_OUT = 0.6V × (1 + R1/R2), allowing independent reconfiguration without PCB modification.

Does the board include thermal management features for the MP5403 QFN20 package?

Yes. The PCB uses exposed thermal pad soldering for U1, multiple internal ground planes, and optimized copper pours under SW1/SW2 nodes and VIN/GND pads - all verified in the provided layout figures (Top/Bottom Layer) to sustain 3.5A/2.5A continuous operation at 25°C ambient.

What load switch capability does EV5403-QB-02A demonstrate?

It demonstrates the MP5403's integrated 3A load switch (VOUT3 path) with 20mΩ R_ON, controlled by EN3. The board routes VIN3 through U1's OUT3 pin, includes test points for VOUT3 monitoring, and supports external enable sequencing independent of the buck regulators.

Are all MP5403 pins accessible on the EV5403-QB-02A board?

Yes - all 20 pins of the QFN20 MP5403 (U1) are routed to test points, headers, or passive components: EN1/EN2/EN3, PG1/PG2/PG3, FB1/FB2, SW1/SW2, VIN1/VIN2/VIN3, GND, AGND, V_SUS, PFL, PFL_ADJ, and OUT3 - enabling full functional verification and probing.