Monolithic Power Systems Inc. EVQ4431-L-00A

Overview

EVQ4431-L-00A from Monolithic Power Systems is a fully assembled and tested evaluation board designed to demonstrate the MPQ4431GL and MP4431 synchronous step-down converters. It delivers 3.3V at up to 1A output current from a 3.3V–36V input range, operates at 450kHz switching frequency, integrates internal 90mΩ high-side and 80mΩ low-side MOSFETs, and supports AEC-Q100 Grade 1 for automotive power systems.

For engineers reviewing the EVQ4431-L-00A datasheet, EVQ4431-L-00A pinout, EVQ4431-L-00A application, or EVQ4431-L-00A equivalent, this board enables rapid validation of wide-input DC/DC conversion, light-load efficiency optimization via AAM mode, external clock synchronization, and configurable soft-start in automotive and industrial power designs.

Technical Context

The EVQ4431-L-00A implements the MPQ4431GL IC in QFN-16 (3mm×4mm) package with wettable flanks, featuring current-mode control, selectable FCCM/AAM operation, and valley-current-based over-current protection with hiccup recovery. Its layout includes optimized EMI filtering (CIN9 damping network), dual-stage input capacitance (22µF electrolytic + parallel ceramic), and precision feedback divider (R7/R8 = 41.2kΩ/13kΩ) for stable 3.3V regulation.

It supports dynamic configuration via EN (1.05V turn-on threshold), SYNC (350kHz–2.5MHz external clock sync with phase selection), FREQ (resistor-programmable switching frequency), and SS (capacitor-adjustable soft-start time). The board's 8.9cm×8.9cm form factor includes test points for VEMI, VOUT, EN, SYNC, and PG signals, enabling real-time waveform capture and load transient analysis.

Key Specifications

Availability

EVQ4431-L-00A is available at Aetrix Electronics and suitable for automotive infotainment power supplies, industrial PLC I/O modules, and battery-powered telematics gateways requiring stable component supply, fast design iteration, and AEC-Q100-compliant reference validation.

Supply support for EVQ4431-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 power management ICs, with expertise in DC/DC conversion, motor drivers, and LED lighting controllers.

The MPQ4431 product line targets automotive and industrial applications demanding wide-input voltage tolerance, low quiescent current, and AEC-Q100 qualification-designed specifically for engine control units, ADAS sensors, and ruggedized power supplies.

FAQ

What input voltage range does the EVQ4431-L-00A support?

The board accepts 3.3V to 36V DC input, validated across cold-crank (3.3V), nominal (12V/24V), and load-dump (36V) conditions per ISO 16750-2. Input EMI filtering includes a 22µF electrolytic capacitor (CIN9) and parallel ceramic capacitors to suppress high-frequency noise and damp ringing.

How is output voltage configured on this evaluation board?

VOUT is fixed at 3.3V using a precision 41.2kΩ/13kΩ resistor divider (R7/R8) connected to the FB pin. The same divider sets loop bandwidth via internal compensation; alternative voltages require replacing both resistors per Table 1 in the reference design guide.

Can the switching frequency be changed, and how?

Yes-frequency is set by an external RFREQ resistor (191kΩ on board for 450kHz). Equation fSW(kHz) = 1.11 × 170000 / RFREQ(kΩ) allows reconfiguration from 350kHz to 2.5MHz; lower values reduce EMI but increase conduction loss, while higher values improve transient response.

What protection features are implemented and how do they behave?

The board inherits MPQ4431GL's valley-current OCP with hiccup-mode recovery, thermal shutdown (>150°C), and low-dropout mode. During overload, it cycles on/off until fault clears; thermal shutdown disables switching and resumes only after die temperature drops below ~140°C hysteresis.

Is synchronization to an external clock supported, and what are the requirements?

Yes-the SYNC pin accepts 350kHz–2.5MHz external clocks. To avoid conflict, the external clock must exceed the RFREQ-set frequency by ≥250kHz. Driving SYNC high at startup forces FCCM; floating or low selects AAM. Phase alignment (in-phase or 180° out-of-phase) is selectable via external logic.

Does the board include a power-good indicator, and how is it used?

Yes-the PG pin outputs an open-drain signal pulled high when VOUT is within ±10% of regulation. On this board, PG connects to a test point and can drive external enable/disable logic or microcontroller interrupts for system-level power sequencing and fault monitoring.