Monolithic Power Systems Inc. EV4458DQT-00A

Overview

EV4458DQT-00A from Monolithic Power Systems is an evaluation board for the MP4458 synchronous step-down converter IC, supporting 36V max input, 3.3V/1A output, and 4MHz switching frequency. It integrates a high-side MOSFET, uses current-mode control, and includes EN, FB, BST, SW, and COMP terminals for full functional validation in high-voltage DC-DC applications.

For engineers reviewing the EV4458DQT-00A datasheet, EV4458DQT-00A pinout, EV4458DQT-00A application, or EV4458DQT-00A equivalent, this board enables rapid prototyping of compact, high-frequency power supplies for automotive, industrial, and battery-powered systems with validated thermal shutdown, frequency foldback, and UVLO.

Technical Context

The EV4458DQT-00A implements the MP4458 QFN10-based buck regulator in a fully assembled, tested layout optimized for 4MHz operation. It supports programmable switching frequency (via R3), adjustable output voltage (via R4/R6 divider), and enable-controlled startup with 1.2V UVLO threshold.

Board-level features include a 10µH/4A shielded inductor (SD8350-100-R), 22µF X5R output capacitor, bootstrap diode (B240A-13-F), and precision 1% feedback resistors - all configured to deliver stable 3.3V/1A output with >90% efficiency across load range.

Key Specifications

Availability

EV4458DQT-00A is available at Aetrix Electronics and suitable for automotive infotainment power rails, industrial sensor node DC-DC conversion, and portable medical device battery regulation requiring stable component supply and fast design validation cycles.

Supply support for EV4458DQT-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, headquartered in California and serving global power management markets since 1997.

The MP4458 product line delivers high-frequency, high-voltage synchronous buck regulators targeting space-constrained applications where EMI reduction, thermal robustness, and light-load efficiency are critical - such as ADAS cameras, PLC I/O modules, and handheld test equipment.

FAQ

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

The EV4458DQT-00A is configured for 3.3V output using a precision resistor divider (R4 = 40.2kΩ, R6 = 124kΩ) that sets the FB pin to 0.8V reference. The output voltage formula is VOUT = 0.8V × (1 + R6/R4), yielding 3.3V within ±1% tolerance. No external compensation components are required for this configuration.

Does the board support 4MHz operation out-of-the-box?

No - the board ships with R3 = 200kΩ, setting switching frequency to ~500kHz. To achieve 4MHz, replace R3 with 93kΩ (±1%). At frequencies above 2MHz, the external bootstrap diode (D2, B240A-13-F) must remain installed to ensure sufficient gate drive voltage for the internal high-side MOSFET.

How is enable and UVLO functionality implemented?

EN pin accepts logic-level control: >1.6V enables regulation, <1.2V disables it. UVLO is implemented via R1 (24.9kΩ) and R2 (100kΩ) divider, setting turn-on threshold at 6V (1.2V × (1 + 100k/24.9k)). This prevents startup under insufficient input voltage and protects downstream circuitry during brown-out conditions.

What inductor and output capacitor are used on the board?

The board uses Cooper Bussmann SD8350-100-R: a 10µH, 4A saturation current, 32mΩ DCR shielded SMD inductor. Output capacitance is 22µF/6.3V X5R (GRM32ER60J226K) in 1210 package, selected for low ESR and stability under 1A load transients at 4MHz switching.

Can this board be used for output voltages other than 3.3V?

Yes - output voltage is resistor-programmable via the FB divider. For example, changing R4 to 20kΩ and R6 to 62kΩ yields 5.0V (0.8V × (1 + 62k/20k)). Recalculation of compensation (C5, R5), inductor ripple current, and output capacitor ESR must follow MP4458 datasheet guidelines to maintain loop stability and transient response.

Is thermal shutdown active and how is it verified?

Yes - the MP4458 IC includes internal thermal shutdown that disables switching when junction temperature exceeds ~150°C. On the EV4458DQT-00A, this is validated via thermal imaging during 1A continuous load at 36V input, showing automatic recovery after cooldown without latch-up or damage to PCB or components.