Monolithic Power Systems Inc. EVQ2451-G-00A

Overview

EVQ2451-G-00A from Monolithic Power Systems is an evaluation board for the MPQ2451 fixed-frequency 2MHz step-down DC/DC converter IC, supporting 8–36V input and delivering regulated 5V/0.6A output with integrated high-side MOSFET, current-mode control, and thermal shutdown protection. It enables rapid validation of high-efficiency power conversion in space-constrained industrial and automotive systems.

For engineers reviewing the EVQ2451-G-00A datasheet, EVQ2451-G-00A pinout, EVQ2451-G-00A application, or EVQ2451-G-00A equivalent, this board provides verified reference design implementation, efficiency characterization across input voltages (8V–36V), soft-start behavior, UVLO threshold configuration (6V default), and EN-controlled enable/disable functionality.

Technical Context

The EVQ2451-G-00A implements the MPQ2451's fixed 2MHz switching frequency to minimize external passive size-using a 3.3μH shielded inductor (WE-744043003) and ceramic capacitors (4.7μF input, 10μF output). Its current-mode control architecture ensures fast transient response and stable operation across 0–0.6A load range.

Board-level features include programmable UVLO via R4/R6 resistor divider (preset to 6V), adjustable output voltage via R1/R2 feedback network (default 5V with R1=23.7kΩ, R2=124kΩ), and EN logic-level interface (1.6V turn-on, 1.2V turn-off) with internal pull-down to ensure safe default-off state.

Key Specifications

Availability

EVQ2451-G-00A is available at Aetrix Electronics and suitable for automotive infotainment power rails, industrial sensor node DC/DC conversion, and distributed battery-powered system validation requiring stable component supply and documented thermal performance.

Supply support for EVQ2451-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 core expertise in DC/DC converters, LED drivers, and motor drivers.

The EVQ2451-G-00A belongs to MPS's evaluation board product line, designed specifically to accelerate design-in of the MPQ2451 family of high-voltage, current-mode buck regulators targeting cost-sensitive, space-constrained applications.

FAQ

What is the default output voltage and how is it set?

The EVQ2451-G-00A delivers 5V output by default, established by the R1 (23.7kΩ) and R2 (124kΩ) resistor divider on the FB pin. The MPQ2451's internal 0.8V reference sets V_OUT = 0.8V × (1 + R1/R2). Replacing R1 adjusts output voltage while maintaining optimal transient response with R2 ≈ 124kΩ.

Does the board support input under-voltage lockout (UVLO), and what is its threshold?

Yes - UVLO is implemented using R4 (26.1kΩ) and R6 (0Ω jumper replaced by resistor for customization). With R6 = 0Ω, UVLO is disabled; with R6 = 10kΩ, threshold becomes 6V per formula: UVLO = 1.2V × (1 + R4/R6). Default board uses R6 = 0Ω, so UVLO is inactive unless modified.

Can the switching frequency be adjusted?

No - the MPQ2451 operates at a fixed 2MHz internal oscillator frequency. This is non-adjustable and hard-coded in the IC; the EVQ2451-G-00A reflects that fixed timing, enabling consistent small-passive sizing without external frequency programming components.

What thermal protection features are implemented?

The board inherits the MPQ2451's internal thermal shutdown, which disables switching when junction temperature exceeds ~150°C and resumes operation after cooldown. No external thermal sensors or fan control circuitry is included - thermal performance relies on PCB copper area and ambient airflow as characterized in MPS Rev. 1.0 test reports.

Is the EN pin pulled up or down by default?

The EN pin has no internal pull-up; it is left floating by default and must be actively driven. Floating EN results in regulator disable due to internal weak pull-down. To enable, apply ≥1.6V (e.g., from microcontroller GPIO); to disable, drive ≤1.2V or leave unconnected.

What is the recommended input capacitor configuration?

The board uses two parallel 4.7μF/50V X7R ceramic capacitors (C1, C2, 1210 package) at the VIN input. This configuration provides low impedance across 100kHz–10MHz, suppresses high-frequency switching noise, and meets MPQ2451's input ripple current rating without requiring bulk electrolytic capacitance.