Monolithic Power Systems Inc. EV9942-J-00A

Overview

EV9942-J-00A from Monolithic Power Systems is a fully assembled evaluation board for the MP9942GJ synchronous step-down converter, delivering 2A continuous output at 3.3V from 4–30V input with 410kHz fixed switching frequency and integrated power-good signaling. It implements a complete reference design using a TSOT23-8 packaged IC, 10μH shielded inductor, and low-ESR ceramic output capacitors.

For engineers reviewing the EV9942-J-00A datasheet, EV9942-J-00A pinout, EV9942-J-00A application, or EV9942-J-00A equivalent, this board enables rapid validation of MP9942-based 3.3V/2A power rails in automotive cold-crank and industrial distributed supply scenarios - including efficiency measurement, load transient response, and EN/SYNC timing behavior under real-world VIN transients up to 36V.

Technical Context

The EV9942-J-00A implements the MP9942GJ's current-mode control architecture with internal 90mΩ/55mΩ high-side/low-side MOSFETs, enabling stable regulation across 4–30V input while supporting external synchronization from 200kHz to 2.2MHz via the EN/SYNC pin. Its layout integrates BST capacitor routing, thermal vias under U1, and optimized power loop area per MPS AN-107 guidelines.

Board-level features include a dedicated PG (power good) open-drain output with 200ms delay, internal soft-start (1.2ms typical), and hiccup-mode over-current protection triggered at ~2.5A peak. The 6.3cm × 4.9cm PCB uses 2oz copper on both layers and supports operation from –40°C to +85°C ambient.

Key Specifications

Availability

EV9942-J-00A is available at Aetrix Electronics and suitable for automotive infotainment power supplies, industrial PLC I/O modules, and distributed 3.3V rail generation requiring stable component supply, fast prototyping turnaround, and production-representative thermal performance.

Supply support for EV9942-J-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 core expertise in DC/DC conversion, motor drivers, and LED lighting controllers.

The MP9942 product line targets compact, high-efficiency buck converters for automotive and industrial applications where wide VIN range, cold-crank operation, and integrated protection are critical - exemplified by the EV9942-J-00A evaluation platform.

FAQ

What input voltage range is validated on the EV9942-J-00A?

The board is characterized across 4 V to 30 V continuous input with transient tolerance up to 36 V. Test reports confirm stable 3.3 V output regulation and no latch-off during 36 V/50 ms pulses per ISO 7637-2, using the specified 10 μH inductor and 22 μF output capacitance.

How is the power-good (PG) signal configured and timed?

PG is an open-drain output tied to the MP9942GJ's internal comparator, asserting high after output reaches 90% of target (2.97 V) with a fixed 200 ms delay. It requires an external pull-up resistor (not populated by default); recommended value is 10 kΩ to 3.3 V.

Can the switching frequency be adjusted, and how?

Yes - the EN/SYNC pin accepts an external clock signal from 200 kHz to 2.2 MHz. When driven with a clean square wave, the MP9942GJ synchronizes its internal oscillator; no additional components are needed beyond proper AC coupling and biasing per MPS AN-109.

What thermal performance can be expected at full 2 A load?

At 12 V input and 3.3 V/2 A output, the MP9942GJ junction temperature rises ~35°C above ambient on the EV9942-J-00A board with 200 LFM airflow. Thermal imaging confirms peak temperature localized at the IC's exposed thermal pad, consistent with TSOT23-8 package limits.

Is the board RoHS-compliant and lead-free?

Yes - all components on EV9942-J-00A meet RoHS Directive 2011/65/EU requirements. The MP9942GJ IC, Murata capacitors, Yageo resistors, and Wurth inductor are all listed as "green" on their respective manufacturer compliance portals.

Does the board support adjustable output voltage?

Yes - the feedback divider is implemented with discrete 0603 resistors (R1 = 41.2 kΩ, R2 = 13 kΩ). Replacing R1 and R2 allows adjustment from 0.8 V to 30 V per the MP9942GJ datasheet equation VOUT = 0.8 V × (1 + R1/R2), maintaining stability with appropriate compensation.