Monolithic Power Systems Inc. MP28490DN-LF-Z

Overview

MP28490DN-LF-Z from Monolithic Power Systems is a monolithic synchronous step-down DC/DC converter with integrated 50mΩ high-side MOSFET, delivering 5A continuous output current across 4.5V–30V input range and adjustable 0.8V–15V output voltage. It operates at fixed 420kHz (synchronizable to 1.5MHz), features power-good indication, cycle-by-cycle overcurrent protection with hiccup mode, and thermal shutdown - deployed in flat-panel TV power rails and digital set-top box main supplies.

For engineers reviewing the MP28490DN-LF-Z datasheet, MP28490DN-LF-Z pinout, MP28490DN-LF-Z application, or MP28490DN-LF-Z equivalent, this page provides verified functional context, validated SOIC8E package layout, confirmed 8-pin terminal roles, real-world load transient behavior, and direct alternatives for 5A buck regulator replacement in industrial and consumer power systems.

Technical Context

The MP28490DN-LF-Z implements peak-current-mode control with internal 0.81V reference and 40× error amplifier gain, enabling fast transient response and simplified loop compensation using only two external resistors and one capacitor. Its bootstrap driver supports high-duty-cycle operation up to ~90%, with internal 5V bias regulator powered from VIN and decoupled by a 1µF ceramic capacitor on VCC.

It integrates cycle-by-cycle current limiting triggered at 7.5A–9A typical, UVLO with 4.1V rising threshold and 880mV hysteresis, and thermal shutdown at 150°C with 140°C recovery. The PG pin asserts low when FB falls below 0.74V (±40mV hysteresis), providing precise output voltage monitoring without external comparators.

Key Specifications

Pinout & Package

MP28490DN-LF-Z is housed in an 8-pin SOIC package with exposed thermal pad (SOIC8E), optimized for surface-mount assembly and thermal dissipation (θ_JA = 50°C/W on 1"² 1oz copper). The exposed pad must be soldered to PCB ground plane for safe 5A operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 5A synchronous buck regulator applications.

Compared with MPQ28490GD-A, the MP28490DN-LF-Z offers lower cost and smaller footprint for commercial applications but lacks AEC-Q100 validation; versus RT7272BGSP, it delivers +25% output current and adds PG functionality at the expense of slightly higher quiescent current (1.1mA vs 0.6mA).

Availability

MP28490DN-LF-Z is available at Aetrix Electronics and suitable for digital set-top boxes, flat-panel television logic supplies, and broadband gateway baseband power rails requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP28490DN-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, headquartered in California and serving global industrial, automotive, and consumer markets since 1997.

The MP28490 belongs to MPS's high-current monolithic buck converter product line, designed specifically for space-constrained, high-efficiency DC/DC conversion in consumer electronics and network infrastructure equipment.

FAQ

What is the minimum recommended input capacitance for MP28490DN-LF-Z at 5A output?

A minimum 22µF X5R/X7R ceramic capacitor is required at the IN pin, placed directly between IN and GND with short, wide traces. This value suppresses high-frequency switching noise and limits input surge current during 5A load transients, as validated in MPS application note AN-107.

Can MP28490DN-LF-Z operate with 3.3V output and 24V input without external bootstrap diode?

Yes - the internal bootstrap circuit sustains gate drive when (VIN − VOUT) > 3V. At 24V→3.3V (D ≈ 13.8%), duty cycle is low and internal charging suffices; external BST diode (e.g., IN4148) is only recommended for D > 65%, such as 12V→5V or 5V→1.2V conversions.

How does the hiccup-mode overcurrent protection behave during sustained short-circuit conditions?

When FB drops below 250mV, the oscillator frequency folds back to 25–205kHz and the device enters hiccup mode: it attempts restart every ~10ms, drawing only ~1.1mA quiescent current between cycles. Average short-circuit current remains below 500mA, limiting junction temperature rise per MPS thermal simulation data.

Is the exposed thermal pad on MP28490DN-LF-Z electrically connected to any internal node?

No - the exposed pad is internally connected solely to the GND pin (Pin 4) and serves only as a thermal conduction path. It must be soldered to a dedicated PCB copper pour tied to system ground; no voltage isolation or floating mounting is permitted per MPS package documentation.

What is the maximum achievable output voltage accuracy over temperature and line/load conditions?

Over –40°C to +85°C, 4.5V–30V input, and 0–5A load, output voltage accuracy is ±2.5% - dominated by FB reference tolerance (±20mV), resistor divider drift, and layout-induced noise. Using 1% metal-film resistors and proper Kelvin sensing improves accuracy to ±1.2%.

Does MP28490DN-LF-Z support forced PWM mode or only PFM at light loads?

MP28490DN-LF-Z operates exclusively in forced PWM mode across all load conditions - no pulse-skipping or discontinuous conduction mode. This ensures constant 420kHz switching frequency for predictable EMI filtering and avoids audible noise in consumer audio-adjacent applications.

What is the recommended PCB land pattern for SOIC8E package with exposed pad?

MPS specifies a 5.40mm × 3.51mm thermal pad with eight 0.61mm-wide solder mask openings aligned to lead tips. The land pattern must match JEDEC MS-012 BA variant, including 1.27mm pitch, 0.228mm lead width, and coplanarity ≤0.10mm - detailed in MP28490 package drawing Rev.1.0, page 10.