Monolithic Power Systems Inc. EV2481-H-01A

Overview

EV2481-H-01A from Monolithic Power Systems is a buck-boost evaluation board for the MP2481 1.2A, 36V white LED driver IC, configured for inverting step-up/down operation with 3-series/9-parallel (27-LED) load, 1.4MHz switching frequency, and dual analog/PWM dimming on a single EN/DIM pin. It supports 4.5–26V input and delivers 180mA per string at up to 85% efficiency.

For engineers reviewing the EV2481-H-01A datasheet, EV2481-H-01A pinout, EV2481-H-01A application, or EV2481-H-01A equivalent, this board enables rapid validation of MP2481-based WLED backlight designs requiring flexible input-to-output voltage relationships, thermal-safe dimming control, and robust fault protection including open-string and short-circuit detection.

Technical Context

The EV2481-H-01A implements the MP2481 in inverting buck-boost topology with JP1 open and JP2 shorted, enabling operation where input voltage may be below, above, or equal to LED output voltage. It uses current-mode control with 1.4MHz fixed-frequency PWM for stable regulation and fast transient response.

Board-level protections include cycle-by-cycle overcurrent limiting, thermal shutdown, open-LED detection via FB monitoring, and output short-circuit protection. Dimming is implemented through a single EN/DIM pin accepting 0.7–1.4V analog voltage or <1kHz PWM signal with defined logic thresholds (ON >1.4V, OFF <0.6V).

Key Specifications

Availability

EV2481-H-01A is available at Aetrix Electronics and suitable for LCD backlight development, automotive interior lighting prototyping, and industrial display power validation requiring stable component supply, pre-validated layout, and documented thermal performance.

Supply support for EV2481-H-01A 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, LED drivers, and motor control solutions.

The MP2481 product line targets wide-input-range WLED backlight drivers for displays where input voltage varies across operating conditions, emphasizing single-pin dimming integration, fault resilience, and minimal external component count.

FAQ

What is the default operating mode of the EV2481-H-01A?

The board is factory-configured for inverting buck-boost mode with JP1 open and JP2 shorted, allowing input voltage to be lower than, higher than, or equal to the LED output voltage-ideal for variable-input applications like automotive battery systems.

How is LED current set on this evaluation board?

LED current is set by the net resistance of R4, R5, and R6 in parallel, with R6 (1.1Ω) installed and R4/R5 open. Using the MP2481's 200mV current-sense threshold, I_LED = 0.200V / R_SENSE, yielding 180mA per string.

Can the EV2481-H-01A be used for step-down-only operation?

Yes-reconfigure JP1 to short and JP2 to open to switch to non-inverting buck mode. This changes the topology to standard step-down, increasing maximum output current capability but restricting VIN to be greater than VOUT.

What are the voltage thresholds for EN/DIM pin control?

The EN/DIM pin turns the device ON when voltage exceeds 1.4V (for PWM high or analog dimming), and OFF when voltage drops below 0.6V. Analog dimming operates linearly between 0.7V and 1.4V; PWM dimming requires high >1.4V and low <0.5V.

Does the board include overvoltage protection, and how is it adjusted?

Yes-OVP is implemented using resistor divider R2/R3 referenced to the internal 1.23V threshold. The OVP trip point is set to ~1.3–1.5× nominal output voltage by selecting R2; default R2 = 100kΩ sets OVP near 24V for typical 3×WLED (~9.6V) output.

Is thermal performance characterized on this board?

Yes-the board layout includes thermal relief pads and copper pours aligned with the MP2481's exposed pad (MSOP8-EP package). Efficiency vs. input voltage data (Fig. 1) and thermal shutdown behavior are documented in Rev. 1.01 of the user guide.