Monolithic Power Systems Inc. MP28265EL-LF-Z

Overview

MP28265EL-LF-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter with integrated 120mΩ high-side and 20mΩ low-side MOSFETs, delivering 5A continuous output current across a 4.5V–21V input range, fixed 1.1MHz switching frequency, and adjustable 0.8V output voltage - deployed in notebook I/O power rails and flat-panel display power supplies.

For engineers reviewing the MP28265EL-LF-Z datasheet, MP28265EL-LF-Z pinout, MP28265EL-LF-Z application, or MP28265EL-LF-Z equivalent, key selection criteria include internal MOSFET R_DS(ON), thermal shutdown at 150°C, power-good open-drain signaling, sync capability from 400kHz–2MHz, and QFN3×4 package thermal resistance (θ_JA = 48°C/W).

Technical Context

The MP28265EL-LF-Z operates in peak-current-mode control with internal compensation, enabling stable regulation without external loop components. Its proprietary switching loss reduction technique and bootstrap-driven high-side gate driver support >85% duty cycle operation up to 21V input.

It integrates a 5V internal VCC regulator powered from VIN, a 0.805V ±12mV precision feedback reference, and dual-level protection: cycle-by-cycle overcurrent limiting (6A typical) plus thermal shutdown with 10°C hysteresis (150°C trip / 140°C recovery).

Key Specifications

Pinout & Package

MP28265EL-LF-Z uses a thermally enhanced 3mm × 4mm, 14-pin QFN package with exposed thermal pad (pin 10). The package supports 2.6W continuous power dissipation at +25°C ambient and features 48°C/W junction-to-ambient thermal resistance on standard 4-layer PCBs per JESD51-7.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RT6253BGQW and TPS54560QDGQRQ1, MP28265EL-LF-Z delivers superior integration (single-chip 5A solution), tighter output accuracy (±1.5% vs ±2%), and optimized thermal performance in space-constrained 3×4mm footprint - making it preferred for consumer computing and display power where board area and BOM count are critical.

Availability

MP28265EL-LF-Z is available at Aetrix Electronics and suitable for notebook I/O power, flat-panel display bias supplies, digital set-top box mainboards, and distributed power systems requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle continuity.

Supply support for MP28265EL-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 power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP28265 belongs to MPS's high-density synchronous buck converter product line, engineered for compact, high-efficiency power delivery in portable and space-constrained computing and display applications.

FAQ

What is the minimum recommended output capacitance for stable operation?

The MP28265EL-LF-Z is optimized for ceramic output capacitors from 10µF to 100µF. For 1.2V/5A operation, a 47µF X7R 0805 ceramic capacitor with ≤5mΩ ESR ensures <20mV peak-to-peak ripple and ≥6dB phase margin. Larger values improve transient response but require rechecking compensation stability.

Can the MP28265EL-LF-Z operate without an external bootstrap capacitor?

No. A 0.1µF–1µF ceramic capacitor between BST and SW pins is mandatory to power the high-side gate driver. Omitting it causes immediate failure of the HS MOSFET turn-on, resulting in no output regulation and potential thermal damage. The internal bootstrap charging circuit requires this external component to function.

How does the EN/SYNC pin behave during external clock synchronization?

When an external clock (400kHz–2MHz) is applied to EN/SYNC, the internal oscillator locks to its rising edge with <5µs jitter. The chip remains enabled regardless of EN voltage level, and the internal 1MΩ pull-down resistor is overridden. Startup occurs within 2ms of clock application, with VOUT settling to regulation before the first sync edge.

What is the purpose of separating AGND and GND pins?

AGND provides a dedicated low-noise reference for the error amplifier, FB comparator, and PG circuitry. It is not internally connected to power GND (pins 12/13). Separating them prevents switching noise from SW and GND currents from corrupting feedback accuracy - essential for achieving <±1% output regulation under dynamic load conditions.

Does the MP28265EL-LF-Z support forced PWM mode at light loads?

No. The MP28265EL-LF-Z operates exclusively in continuous conduction mode (CCM) across its full 0–5A load range. It does not enter discontinuous conduction mode (DCM) or pulse-frequency modulation (PFM) at light loads. Efficiency below 0.5A drops gradually due to fixed switching losses, but regulation remains stable without audible switching noise.

What is the maximum allowable input voltage ripple at 5A load?

At 5A output, the MP28265EL-LF-Z tolerates ≤100mV_P-P input ripple when using a 22µF X5R ceramic input capacitor. Exceeding this causes increased RMS current stress on C1 and may trigger UVLO if ripple dips below 4.0V. For 21V input, a 33µF/25V X7R capacitor is recommended to maintain margin.

How is thermal performance affected by the exposed pad soldering?

Full solder coverage of the exposed thermal pad (pin 10) to a ≥100mm² internal copper pour is required to achieve the specified θ_JA = 48°C/W. Incomplete soldering or undersized thermal vias increases junction temperature by 15–25°C at 5A, potentially triggering thermal shutdown prematurely. Use ≥6 thermal vias (0.3mm diameter) under the pad.