Monolithic Power Systems Inc. MP28275EL-LF-P

Overview

MP28275EL-LF-P from Monolithic Power Systems is a synchronous step-down DC/DC converter IC with integrated 120mΩ high-side and 20mΩ low-side MOSFETs, delivering 5A continuous output current from a 4.5V–7V input. It operates at a fixed 1.1MHz switching frequency with internal compensation, supports external clock synchronization (300kHz–2MHz), and features power-good indication, thermal shutdown, and hiccup-mode over-current protection. Used in notebook I/O power rails requiring compact, high-efficiency regulation.

For engineers reviewing the MP28275EL-LF-P datasheet, MP28275EL-LF-P pinout, MP28275EL-LF-P application, or MP28275EL-LF-P equivalent, key selection criteria include input voltage range (4.5–7V), output current capability (5A), thermal performance in QFN14 (θJA = 48°C/W), feedback reference accuracy (789–821mV), and EN/SYNC dual-function pin behavior for enable control or frequency synchronization.

Technical Context

The MP28275EL-LF-P implements peak-current-mode control with a fixed 1.1MHz oscillator and internal error amplifier referenced to an 805mV typical FB threshold. Its proprietary switching loss reduction technique enhances efficiency across load range, while cycle-by-cycle current limiting and hiccup-mode fault recovery protect against sustained overloads.

It integrates a 5V VCC regulator powered from VIN, bootstrap circuitry for high-side gate drive, and a dedicated open-drain PG pin with 90%/70% hysteresis relative to VFB. The EN/SYNC pin serves as both logic-enable input (1.1–1.6V rising threshold) and external clock sync interface up to 2MHz.

Key Specifications

Pinout & Package

MP28275EL-LF-P is housed in a thermally enhanced 3mm × 4mm, 14-pin QFN package with exposed thermal pad (connected to GND). Pin 10 (exposed pad) is NC but must be soldered to PCB ground plane for optimal thermal performance (θJC = 11°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with RT6220AGQW and TPS54560BQPWPRQ1, MP28275EL-LF-P offers superior integration (internal MOSFETs, BST cap support, PG), tighter input range optimization (4.5–7V), and smaller footprint (3×4mm QFN14), making it ideal for space-limited consumer electronics where 5–7V input rails dominate.

Availability

MP28275EL-LF-P is available at Aetrix Electronics and suitable for notebook I/O power, networking system core supplies, digital set-top box SoC cores, and flat panel display TCON supplies requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP28275EL-LF-P 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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP28275 belongs to MPS's high-frequency synchronous buck converter product line, engineered for compact, high-efficiency point-of-load regulation in portable and space-constrained computing and consumer electronics.

FAQ

What is the minimum recommended input capacitance for MP28275EL-LF-P?

The datasheet specifies a 22µF X5R/X7R ceramic capacitor at the IN pin as sufficient for most applications. This value provides adequate RMS current handling (≥2.5A) and low impedance at 1.1MHz to suppress input voltage ripple. A 0.1µF ceramic capacitor must also be placed adjacent to the IN and GND pins for high-frequency decoupling.

Can MP28275EL-LF-P operate with an output voltage below 0.8V?

No. The internal feedback reference is fixed at 0.8V nominal, and the device is not designed for sub-0.8V regulation. Output voltage is set by VOUT = 0.8V × (1 + R1/R2); attempting lower outputs violates the FB pin's operating range and causes regulation failure or instability.

How does the EN/SYNC pin behave when used for external clock synchronization?

When an external clock signal (300kHz–2MHz) is applied to EN/SYNC, the internal oscillator locks to its rising edge. Startup occurs 2ms after the first valid sync edge, and the internal clock remains phase-aligned. During sync mode, the EN function is disabled-logic-level enable control is not available simultaneously.

Is an external bootstrap diode required for MP28275EL-LF-P?

An external bootstrap diode (e.g., IN4148) is optional and recommended only when duty cycle exceeds 65% (e.g., VOUT > 4.55V with 7V input). It improves BST capacitor charging efficiency under high-duty conditions but is unnecessary for typical 1.2V–2.5V outputs from 5V input.

What is the maximum achievable output current at 85°C ambient temperature?

With a 4-layer PCB per JEDEC JESD51-7, 2.6W max power dissipation, and θJA = 48°C/W, the junction temperature rise at 5A is ~125°C above ambient. At TA = +85°C, TJ reaches ~210°C-exceeding the 150°C limit. Derating to ~3.5A maintains TJ ≤150°C; actual limit depends on PCB copper area and airflow.

Does MP28275EL-LF-P support forced PWM mode at light loads?

No. The MP28275EL-LF-P operates exclusively in peak-current-mode PWM and does not include pulse-skipping or forced continuous conduction mode (FCCM) control. Light-load efficiency relies on reduced switching losses and low quiescent current (1mA), not mode switching.

How is the power-good (PG) signal asserted during startup?

PG asserts high (open-drain pulled up externally) only after VOUT reaches ≥90% of the target voltage and remains stable. It deasserts low when VOUT falls ≤70% of target. The 20µs PG delay ensures transient settling before signaling valid regulation.