Monolithic Power Systems Inc. EV9943-Q-00A

Overview

EV9943-Q-00A from Monolithic Power Systems is an evaluation board for the MP9943GQ synchronous step-down converter, demonstrating a 36V-input, 5V-output, 3A peak buck regulator with 410kHz fixed switching frequency, internal 85mΩ/55mΩ MOSFETs, and power-good signaling - deployed in automotive cold-crank and distributed power systems.

For engineers reviewing the EV9943-Q-00A datasheet, EV9943-Q-00A pinout, EV9943-Q-00A application, or EV9943-Q-00A equivalent, this board enables rapid validation of MP9943GQ's transient response, thermal behavior, power-good timing, and EN/SYNC-controlled startup/shutdown under real-world load conditions up to 3A peak.

Technical Context

The EV9943-Q-00A implements the MP9943GQ IC in a fully assembled, tested QFN8 (3mm × 3mm) layout with optimized power-path routing, integrated 10μH shielded inductor (Wurth 744314101), and low-ESR ceramic output capacitors (22μF ×2, 10μF ×2). It supports both VIN- and EN-triggered startup and shutdown sequences.

Test results confirm stable 5V output across 0–3A load steps at 12V input, with <20mV AC-coupled ripple, fast PG assertion (<100μs), and robust short-circuit protection with hiccup-mode recovery - all verified per Rev.1.0 schematic and BOM using Murata GRM32ER71C226KE79 and GRM32ER71H106KA12L capacitors.

Key Specifications

Availability

EV9943-Q-00A is available at Aetrix Electronics and suitable for automotive power validation, industrial DC-DC reference design verification, and consumer multi-function printer (MFP) power subsystem prototyping requiring stable component supply and traceable evaluation hardware.

Supply support for EV9943-Q-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 analog semiconductor company specializing in high-performance power management ICs, with core expertise in DC-DC conversion, LED drivers, and motor control solutions.

The MP9943 product line delivers compact, high-efficiency buck regulators for automotive, industrial, and consumer applications where wide input range, cold-crank operation, and integrated power-good signaling are critical.

FAQ

What is the primary function of the EV9943-Q-00A evaluation board?

The EV9943-Q-00A is a fully assembled demonstration platform for the MP9943GQ synchronous step-down converter. It provides immediate access to validated circuitry, test points, and thermal layout for evaluating 36V-input, 5V/3A output performance - including startup timing, load transient response, power-good assertion, and hiccup-mode overcurrent recovery - without custom PCB development.

Can the output voltage be adjusted, and how is it configured?

Yes - the board ships with a fixed 5V output set by R7 (41.2kΩ) and R8 (7.68kΩ) feedback divider, but the MP9943GQ supports adjustable output from 0.8V using external resistors. The BOM includes footprint space for alternate resistor values, and the schematic shows direct connection to the FB pin for reconfiguration per application requirements.

How does the EN/SYNC pin operate on this board?

The EN/SYNC pin serves dual functions: applying >1.4V enables regulation and <1.25V disables it; applying a clean external clock signal (200kHz–2.2MHz) synchronizes switching to reduce EMI. Test waveforms in the user guide confirm clean startup/shutdown edges and stable frequency lock under sync mode.

What protection features are demonstrated on the EV9943-Q-00A?

The board validates MP9943GQ's full protection suite: over-current protection with hiccup-mode recovery (verified via SCP entry/recovery waveforms), thermal shutdown (observed during sustained 3A load at elevated ambient), and input overvoltage tolerance up to 36V - all confirmed in the Rev.1.0 test report with oscilloscope captures.

Is the board RoHS-compliant and lead-free?

Yes - all components on the EV9943-Q-00A meet RoHS Directive requirements. MPS confirms full lead-free compliance for the MP9943GQ IC and associated passive components, including Murata GRM-series ceramics and Yageo RC0603 film resistors listed in the official BOM.

Does the board include thermal management provisions?

Yes - the MP9943GQ is mounted on a QFN8 package with exposed thermal pad soldered to a dedicated copper pour on the bottom layer, connected via multiple thermal vias. Layout documentation (Fig. 2 and Fig. 3) confirms 2oz copper and optimized ground/power plane separation to sustain 3A peak operation at TA = 25°C without forced airflow.