Monolithic Power Systems Inc. MP28266DL-LF-Z

Overview

MP28266DL-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 up to 3A continuous output current across a 6V–21V input range, fixed 500kHz switching frequency, and 0.6V ±2% internal reference-designed for compact power rails in DSL modems and set-top boxes.

For engineers reviewing the MP28266DL-LF-Z datasheet, MP28266DL-LF-Z pinout, MP28266DL-LF-Z application, or MP28266DL-LF-Z equivalent, key selection criteria include its AAM power-save mode behavior, SYNC frequency range (300kHz–2MHz), thermal shutdown threshold (150°C), and QFN14 (3×4mm) package layout requirements for high-current SW/GND routing.

Technical Context

The MP28266DL-LF-Z employs peak-current-mode control with an internal 0.6V reference and error amplifier driving COMP voltage to regulate output. Its synchronous rectification eliminates external diode losses, while the bootstrap circuit (BST pin + external capacitor) enables high-side gate drive above VIN.

It supports external frequency synchronization via the SYNC pin, features programmable soft-start through the SS pin (10µA current source), and implements hiccup-mode over-current protection triggered when FB drops below 70% of reference during current-limit violation-ensuring fault resilience without latch-off during startup.

Key Specifications

Pinout & Package

MP28266DL-LF-Z is housed in a thermally enhanced 3mm × 4mm QFN-14 package with exposed pad (no internal connection) requiring PCB-level GND tie for optimal thermal performance (θ_JA = 48°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP28266DL-LF-Z, MP28164DJ-LF-Z trades input range and feature set for smaller footprint and lower cost in low-voltage apps, while RT7295BGJ8F offers similar current capability but lacks critical system-level controls like SYNC and AAM-limiting design flexibility in multi-rail or energy-conscious deployments.

Availability

MP28266DL-LF-Z is available at Aetrix Electronics and suitable for DSL modems, cable modems, set-top boxes, and industrial gateways requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP28266DL-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.

The MP28266 belongs to MPS's high-efficiency synchronous buck converter product line, engineered for space-constrained broadband and industrial applications demanding wide input range, robust protection, and minimal external components.

FAQ

What is the minimum recommended input capacitance for MP28266DL-LF-Z?

A 22µF low-ESR ceramic capacitor (X5R/X7R) is recommended at the IN pin, placed as close as possible with wide traces and multiple vias to GND. For high-ripple applications, add a 0.1µF ceramic in parallel near the IC to suppress high-frequency noise and stabilize the internal VCC regulator.

Can MP28266DL-LF-Z operate without an external bootstrap capacitor?

No. The BST pin requires a 0.1µF ceramic capacitor connected between BST and SW pins to form the floating supply for the high-side gate driver. Omitting it disables the HS MOSFET, causing failure to regulate and potential damage due to uncontrolled LS conduction.

How does the AAM pin affect light-load efficiency and output ripple?

Driving AAM above 2.9V forces CCM mode, improving transient response but increasing light-load quiescent current (~0.7mA). Setting AAM near 2.2V enables AAM mode, reducing I_q to ~0.45mA but increasing output ripple; optimal bias balances both based on measured V_OUT ripple and standby power targets.

Is MP28266DL-LF-Z compatible with ceramic output capacitors only?

It supports ceramic, tantalum, or low-ESR electrolytic output capacitors. Ceramic is preferred for low ESR and stable capacitance vs. bias/voltage; for 1.2V/3A, ≥22µF X5R/X7R is typical. Tantalum or polymer caps require careful ESR selection to maintain loop stability per the internal Type-II compensation.

What happens during a short-circuit event on the output?

When V_FB drops below 100mV (70% of 0.6V reference) while current limit is exceeded, the device enters hiccup mode: it shuts down for ~3ms, then attempts restart. This cycle repeats until fault clears, limiting average power dissipation and preventing thermal damage without requiring external circuitry.

Does MP28266DL-LF-Z support forced PWM mode?

No. It operates in automatic AAM/DCM/CCM mode based on load and AAM pin voltage. There is no dedicated pin or register to force continuous PWM; CCM is only achieved by raising AAM above the critical COMP voltage (typically >2.9V), which eliminates DCM but does not disable AAM entirely.

What is the maximum allowable thermal resistance for reliable 3A operation?

At TA = +85°C, θ_JA must be ≤33°C/W to keep junction temperature ≤125°C (derated from 150°C max). With θ_JA = 48°C/W (standard 4-layer board), full 3A load requires active cooling or reduced ambient; use the exposed pad tied to ≥2cm² GND copper area to approach θ_JA ≈ 35°C/W.