Monolithic Power Systems Inc. MP28490DN-LF

Overview

MP28490DN-LF 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. It operates at fixed 420kHz switching frequency (synchronizable up to 1.5MHz), features power-good indicator, cycle-by-cycle overcurrent protection with hiccup mode, and thermal shutdown - deployed in flat-panel TV power rails and broadband communication equipment.

For engineers reviewing the MP28490DN-LF datasheet, MP28490DN-LF pinout, MP28490DN-LF application, or MP28490DN-LF equivalent, key selection criteria include its 0.8V–15V adjustable output, SOIC8E thermally enhanced package with exposed pad, internal bootstrap driver architecture, and compatibility with low-ESR ceramic output capacitors without external compensation network.

Technical Context

The MP28490DN-LF implements peak-current-mode control with a fixed 420kHz oscillator, enabling fast transient response and simplified loop stabilization. Its internal 5V bias regulator powers all circuitry across full VIN range, while the floating high-side gate driver relies on an external bootstrap capacitor between SW and BST pins for gate voltage boosting.

Functional blocks include a 40× transconductance error amplifier comparing FB voltage against 0.81V internal reference, PWM comparator with 90% maximum duty cycle limit, and hiccup-mode fault recovery triggered when FB drops below 0.74V (indicating >10% output undervoltage). UVLO activates at 4.1V rising threshold with 880mV hysteresis.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with MP2315DJ-LF-Z and TPS54560BQDDARQ1, the MP28490DN-LF delivers optimal balance of 5A capability, thermal performance via exposed pad, PG signaling, and 420kHz EMI profile - making it the preferred choice for cost-sensitive, high-volume consumer electronics requiring reliable 5A buck conversion.

Availability

MP28490DN-LF is available at Aetrix Electronics and suitable for flat panel television power rails, digital set-top box core supplies, and broadband communications equipment requiring stable component supply and long-term production continuity.

Supply support for MP28490DN-LF 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, computing, and consumer markets since 1997.

The MP28490 belongs to MPS's high-current integrated buck converter product line, designed specifically for space- and thermally constrained consumer electronics needing 3–5A output with minimal external components and robust fault protection.

FAQ

What is the minimum recommended input capacitance for MP28490DN-LF?

A 22µF X5R or X7R ceramic capacitor is recommended at the IN pin, placed as close as possible to pins 4 (GND) and 8 (IN). This value suppresses high-frequency switching noise and limits surge current; lower values may cause input voltage droop under 5A load transients.

Can MP28490DN-LF operate without an external bootstrap diode?

Yes - the internal bootstrap charging circuit functions reliably without an external diode for most output voltages. An external IN4148 is only recommended when V_OUT = 3.3V or 5V and duty cycle exceeds 65%, to improve light-load efficiency by reducing BST capacitor discharge path losses.

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

When FB falls below 0.74V due to overload, the device enters hiccup mode: it disables switching, waits ~10ms, then attempts restart. This cycle repeats, limiting average short-circuit current to ~1.5A and junction temperature to <125°C - preventing permanent damage during board-level faults.

Is the exposed thermal pad electrically connected internally?

No - the exposed pad is a dedicated thermal slug, not tied to any internal node. It must be soldered to a PCB copper pour connected to GND for optimal heat dissipation; electrical connection to GND is recommended but not required for functionality.

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

Output voltage accuracy is ±2.5% over –40°C to +85°C, 4.5V–30V input, and 0–5A load, based on 0.788V–0.828V feedback reference tolerance and internal error amplifier gain. External resistor tolerance dominates final accuracy - use 1% FB dividers for ≤1% total error.

Does MP28490DN-LF require external compensation components?

No - the error amplifier uses an optimized internal compensation network. Only the external FB resistor divider and input/output capacitors are required; no external RC networks or type-II/type-III compensators are needed for stable operation across all operating conditions.

How is the EN/SYNC pin configured for standalone enable versus external clock synchronization?

Pull EN/SYNC to VIN for automatic startup; pull to GND for shutdown (≥5µs pulse required). For synchronization, apply a clean 300kHz–1.5MHz CMOS clock with ≥1.2V high level - the internal oscillator locks to the rising edge, eliminating beat frequencies in multi-rail systems.