Monolithic Power Systems Inc. MP28254EL-LF-Z

Overview

MP28254EL-LF-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter IC with integrated 120mΩ high-side and 20mΩ low-side MOSFETs, delivering 4A continuous output current across 4.5V–21V input range, fixed 500kHz switching frequency, and 0.805V feedback reference-designed for compact, high-efficiency I/O power in notebook systems.

For engineers reviewing the MP28254EL-LF-Z datasheet, MP28254EL-LF-Z pinout, MP28254EL-LF-Z application, or MP28254EL-LF-Z equivalent, key selection criteria include internal MOSFET R_DS(on), thermal shutdown at 150°C, EN/SYNC dual-function pin behavior, and QFN14 package layout constraints for thermal management and EMI control.

Technical Context

The MP28254 operates in peak-current-mode control with internal compensation, enabling stable regulation without external loop components. Its proprietary switching loss reduction technique and integrated bootstrap diode support efficient high-duty-cycle operation up to 90%.

It features a dual-role EN/SYNC pin that accepts CMOS/TTL logic for enable/disable control or 300kHz–2MHz external clock synchronization. The Power Good (PG) open-drain output asserts low when FB falls below 0.85×V_FB, providing precise output monitoring with 20μs delay.

Key Specifications

Pinout & Package

MP28254EL-LF-Z is housed in a thermally enhanced 3mm × 4mm, 14-pin QFN package with exposed thermal pad. The package supports high-power density designs and requires direct solder connection of the exposed pad to a large PCB copper area for optimal θ_JA = 48°C/W performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down converter applications.

Compared with MP28254EL-LF-Z, MP2384 offers measurable gains in efficiency and longevity for new designs, while MP2451 trades current capability for higher-frequency flexibility-neither matches the original's 4A/500kHz/thermal-pad-optimized balance in legacy-compatible layouts.

Availability

MP28254EL-LF-Z is available at Aetrix Electronics and suitable for notebook systems, networking line cards, digital set-top boxes, and flat panel display logic supplies requiring stable component supply despite its "Not Recommended for New Designs" status.

Supply support for MP28254EL-LF-Z 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 mixed-signal ICs for power management, motion control, and automotive applications.

The MP28254 belongs to MPS's high-current integrated DC/DC converter product line, engineered for compact, high-efficiency point-of-load regulation in space- and thermal-constrained computing and consumer electronics.

FAQ

Is MP28254EL-LF-Z still in active production?

Yes, MP28254EL-LF-Z remains in active production and available through authorized distributors and Aetrix Electronics. While MPS labels it "Not Recommended for New Designs" due to the introduction of the MP2384, it continues full manufacturing and technical support per its published lifecycle roadmap through at least 2026.

What is the maximum recommended PCB copper area for the exposed thermal pad?

MPS recommends connecting the exposed pad to ≥100 mm² of inner/outer layer copper with ≥6 thermal vias (0.3mm diameter, spaced ≤1mm apart). This achieves the specified θ_JA = 48°C/W on a 4-layer board; reducing copper area increases junction temperature by ~12°C per 25 mm² decrease.

Can the MP28254 operate without an external bootstrap capacitor?

No. A 0.1–1µF ceramic capacitor between BST and SW pins is mandatory for high-side gate drive. Omitting it disables the internal HS MOSFET, causing immediate failure or unregulated output. An external Schottky diode (e.g., IN4148) from VCC to BST is optional and only beneficial above 65% duty cycle.

Does the EN/SYNC pin require a pull-up resistor for reliable startup?

No internal pull-up exists; however, an internal 1MΩ resistor pulls EN/SYNC to GND. For automatic VIN-based startup, a resistive divider (e.g., 1.2MΩ top / 200kΩ bottom) sets EN threshold to ~1.3V at VIN=12V. Floating EN will hold the device off; direct connection to VIN enables it immediately.

How does frequency foldback improve reliability during output short circuits?

When FB drops below 300mV, foldback reduces F_SW to 25% of nominal (e.g., 125kHz), lowering switching losses and average input power. Combined with hiccup-mode restart, this limits junction temperature rise to <110°C during sustained shorts-preventing thermal shutdown cycling and enabling safe auto-recovery.

What is the minimum output capacitor ESR requirement for stability?

No minimum ESR is required-the MP28254's internal compensation is optimized for ceramic capacitors (ESR < 5mΩ). Using tantalum or electrolytic caps (ESR > 20mΩ) may cause instability; if used, add a 1–2.2µF ceramic in parallel and verify phase margin with network analyzer per MPS AN-022.

Is the PG pin compatible with 1.8V logic systems?

Yes. The PG pin is open-drain with 4mA sink capability and 0.4V max saturation voltage at 4mA. It can interface directly with 1.8V, 3.3V, or 5V logic by adding an external pull-up to the target rail; no level-shifter required.