Monolithic Power Systems Inc. EV3421-G-00A

Overview

EV3421-G-00A from Monolithic Power Systems is an evaluation board designed to demonstrate the MP3421 synchronous step-up converter, a 5.5A, 600kHz current-mode DC/DC boost IC with true output disconnect, 1.9V–5.5V input range, and integrated P-channel MOSFET. It delivers up to 5V/2.1A from 2.8–4.2V input and supports inrush limiting, OCP, SCP, OVP, and OTP protection in battery-powered USB power applications.

For engineers reviewing the EV3421-G-00A datasheet, EV3421-G-00A pinout, EV3421-G-00A application, or EV3421-G-00A equivalent, this board enables rapid validation of MP3421's 600kHz fixed-frequency operation, internal soft-start, QFN2×2-14 footprint, 43µA quiescent current, and output disconnect behavior under real load conditions.

Technical Context

The EV3421-G-00A implements the MP3421 IC in a fully assembled, tested layout optimized for 5V output using a 1.5µH shielded inductor and four 22µF X7R ceramic output capacitors. The board routes all critical high-current paths-including SW, PGND, and AGND-with low-inductance copper pours and separates analog and power grounds per MP3421's current-mode control requirements.

It integrates discrete feedback resistors (R1=787kΩ, R2=150kΩ) to set VOUT=5V via the 0.807V FB reference, supports external EN control (1.2V turn-on threshold), and requires INA tied to VIN per design note-enabling accurate input current monitoring only when configured correctly.

Key Specifications

Availability

EV3421-G-00A is available at Aetrix Electronics and suitable for battery-powered portable electronics, USB power delivery validation, and consumer accessory power architecture development requiring stable component supply and fast time-to-test.

Supply support for EV3421-G-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, motor drivers, and LED lighting controllers.

The MP3421 product line targets ultra-compact, high-efficiency boost converters for single-cell Li-ion and Li-polymer battery systems where output disconnect, low quiescent current, and robust protection are mandatory.

FAQ

What input voltage range is supported on the EV3421-G-00A board?

The board is rated for 2.8–4.2V input but can operate as low as 1.9V with reduced output current capability. Input above 4.2V may trigger down-mode operation and increased power loss when VIN approaches VOUT, per design note in the revision 1.0 documentation.

How is the output voltage set, and can it be adjusted?

VOUT is set to 5V by default using R1=787kΩ and R2=150kΩ, referencing the MP3421's 0.807V FB pin. It can be adjusted using the formula VOUT = VFB × (R1 + R2)/R2; changing R2 alters the division ratio while maintaining stability per the IC's internal compensation.

Does the board implement true output disconnect, and how is it verified?

Yes-the MP3421 IC internally disconnects the output from input via a P-channel MOSFET during shutdown. On EV3421-G-00A, this is confirmed by measuring open-circuit VOUT after disabling EN or removing VIN, with no backfeed observed across the SW node or output capacitors.

What is the role of the INA pin, and how must it be connected?

INA monitors input current and must be shorted to VIN per Note 2 in the schematic. Leaving INA floating or misconnected invalidates current-sense accuracy and may affect inrush limiting or OCP response, as the MP3421 relies on this path for internal current-mode control loop stability.

Which components define the board's thermal performance under full load?

Thermal performance at 2.1A/5V is defined by the 1.5µH Wurth 744311150 inductor (RDC=6.6mΩ, Isat=14A), four parallel 22µF Murata GRM32ER71A226KE20L output capacitors, and the MP3421GG's QFN2×2-14 package mounted directly to 2oz copper thermal pads-verified in test reports at TA=25°C with no forced airflow.

Can the board be used with input sources outside the 2.8–4.2V range without modification?

Yes-but operation below 2.8V reduces maximum deliverable output current due to duty-cycle limits and lower headroom; operation above 4.2V risks entering inefficient down-mode and excessive conduction loss in the internal PMOS disconnect switch, as documented in the Rev.1.0 notes.