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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Monolithic Power Systems Inc. MP28255EL-LF-Z

Name: MP28255EL-LF-Z
Brand: Monolithic Power Systems Inc.
SKU: MP28255EL-LF-Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MP28255EL-LF-Z

Manufacturer:: Monolithic Power Systems Inc.

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 14-VFDFN Exposed Pad

Datasheet:: MP28255EL-LF-Z.pdf

Description:: IC REG BUCK ADJ 4A 14QFN

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Product details

Overview

MP28255EL-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 4A continuous output current across a 4.5V–21V input range, fixed 500kHz switching frequency, and adjustable 0.8V output voltage-used in flat-panel TV power rails for stable core voltage regulation.

For engineers reviewing the MP28255EL-LF-Z datasheet, MP28255EL-LF-Z pinout, MP28255EL-LF-Z application, or MP28255EL-LF-Z equivalent, key selection criteria include internal MOSFET R_DS(ON), thermal shutdown at 150°C, EN/SYNC dual-function pin, PG open-drain status signaling, and QFN3x4 package thermal resistance (θ_JA = 48°C/W).

Technical Context

The MP28255 operates in peak-current-mode control with fixed 500kHz oscillator and internal compensation, enabling fast transient response without external loop components. Its proprietary switching loss reduction technique and integrated bootstrap diode support efficient high-duty-cycle operation up to 90%.

It implements cycle-by-cycle over-current protection with hiccup-mode recovery during short-circuit faults and uses separate AGND and GND pins to isolate analog feedback paths from power ground noise-critical for maintaining ±1.5% output voltage accuracy (V_FB = 789–824mV) across –40°C to +85°C.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4.5V to 21V - supports wide industrial and consumer input rails including 5V, 12V, and 19V adapters.
Output Current	4A continuous - sustains full load without derating at T_A ≤ 65°C with proper PCB copper area.
Switching Frequency	Fixed 500kHz (±15%) - enables compact magnetics and predictable EMI filtering design.
Feedback Reference	0.805V ±1.5% - sets output voltage via resistor divider; enables 0.8V minimum adjustable V_OUT.
HS/LS R_DS(ON)	120mΩ / 20mΩ - minimizes conduction loss; achieves >92% efficiency at 1.2V/4A, 12V_IN.
Thermal Shutdown	150°C with 10°C hysteresis - protects die during sustained overload; resumes operation at ~140°C.
Power Good Threshold	0.7V_FB (falling), 0.9V_FB (rising) - provides accurate ±3% output monitoring for system sequencing.
Soft-Start Time	2–6.5ms with 47nF capacitor - prevents inrush current; programmable via SS pin capacitor.

Pinout & Package

The MP28255EL-LF-Z is housed in a thermally enhanced 3mm × 4mm, 14-pin QFN package with exposed thermal pad (connected to GND). Pin 1 is marked by a dot; the exposed pad must be soldered to a dedicated GND plane for optimal θ_JA = 48°C/W performance.

Pin/Terminal	Circuit Role	Design Meaning
1 IN	Input supply rail	Accepts 4.5–21V; requires local 22μF ceramic decoupling and low-impedance PCB routing.
2,3,4,5 SW	Switch node	High-current path to inductor; must use wide traces and multiple vias to minimize parasitic inductance.
6 BST	Bootstrap supply	Connects to SW via 0.1–1μF capacitor; powers high-side gate driver; supports optional IN4148 diode.
7 EN/SYNC	Enable & clock sync	Dual-function: logic-enable (1.3V threshold) or external 300kHz–2MHz sync signal input.
8 FB	Feedback input	Senses output voltage via resistor divider; internal 805mV reference enables precise V_OUT setting.
9 PG	Power good indicator	Open-drain output; asserts low when V_OUT drops below 70% of target; used for system power sequencing.
10,11 SS, VCC	Soft-start control & bias supply	SS sets startup ramp time; VCC is internal 5V regulator (0.1μF decoupling required).
12,13 GND, AGND	Power & signal ground	GND carries high-current return; AGND is isolated analog reference-must connect externally to GND on PCB.
14 -	Exposed thermal pad	No internal connection; mandatory GND tie for thermal management and EMI reduction.

Key Features

Feature	Design Value
Integrated MOSFETs	120mΩ HS + 20mΩ LS switches eliminate external FETs and drivers, reducing BOM count and layout complexity.
Internal Compensation	Single-pole compensation network eliminates need for external Type-II/III compensation components.
Sync Capability	EN/SYNC pin accepts 300kHz–2MHz external clock, enabling deterministic EMI reduction in multi-rail systems.
Hiccup-Mode OCP	Enters periodic restart on sustained overcurrent, limiting average fault current and preventing thermal runaway.
Separate AGND/GND	Prevents switching noise from corrupting feedback sensing-ensures stable regulation under dynamic load steps.
Proprietary Loss Reduction	Optimizes gate drive timing and body diode conduction to reduce switching losses at high duty cycles (>65%).

Applications

Networking Systems

Digital Set Top Boxes

Use Scenario: Powering FPGA I/O banks and DDR memory interfaces in enterprise switches.

IC Role / Device Role / Timing Role: Primary 1.2V/4A point-of-load regulator with PG signaling for FPGA configuration sequencing.

Use Value: Internal MOSFETs and 500kHz operation enable <15mm² solution size while maintaining <±1.5% output regulation under 0–4A load transients.

Use Scenario: Generating 1.8V core supply for MPEG decoder SoCs in cable/satellite receivers.

IC Role / Device Role / Timing Role: Synchronous buck controller with adjustable soft-start to meet STB power-up timing requirements.

Use Value: 0.8V reference and external resistor divider allow precise 1.8V output matching SoC VDD tolerance (±3%), verified across –20°C to +85°C.

Flat Panel Television

Distributed Power Systems

Use Scenario: Supplying 2.5V logic rail for TCON (timing controller) and LVDS transmitter in 4K LCD panels.

IC Role / Device Role / Timing Role: High-efficiency intermediate bus converter stepping down 12V to 2.5V with hiccup-mode fault protection.

Use Value: 92% peak efficiency at 2.5V/4A reduces heat buildup behind narrow bezel enclosures; thermal shutdown prevents panel blackouts.

Use Scenario: Providing isolated 3.3V auxiliary supply in telecom line cards with strict ripple limits (<20mV_pp).

IC Role / Device Role / Timing Role: Compact, low-noise POL regulator with ceramic-capacitor-optimized stability and PG confirmation.

Use Value: Internal compensation and 0.1μF VCC decoupling ensure stable operation with X5R/X7R ceramics-eliminating electrolytic capacitor aging concerns.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP28164DJ-LF-Z	Lower 3A rating, 2.5–18V input, 600kHz f_SW, same QFN3x4 package	Not suitable for 4A loads; better for space-constrained 3A applications with tighter EMI budgets	Select when output current ≤3A and higher switching frequency improves filter size.
RT7295BGJ8F	4A rating, 4.5–18V input, 600kHz f_SW, different 16-pin QFN package, no integrated BST diode	Requires external bootstrap diode; lacks hiccup-mode OCP; PG threshold differs (85%/75% V_FB)	Choose only if board redesign accommodates pinout change and external BST diode placement.

Compared with MP28255EL-LF-Z, MP28164DJ-LF-Z trades current capability for higher frequency and smaller inductors, while RT7295BGJ8F offers similar current but demands additional components and lacks robust short-circuit recovery-making MP28255 the preferred choice for 4A, thermally constrained, or fault-resilient designs.

Availability

MP28255EL-LF-Z is available at Aetrix Electronics and suitable for networking systems, digital set-top boxes, flat-panel television power supplies, and distributed power systems requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle continuity.

Supply support for MP28255EL-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 MP28255 belongs to MPS's high-density synchronous buck converter product line, engineered for compact, high-efficiency DC/DC conversion in space- and thermal-constrained consumer and industrial equipment.

FAQ

What is the minimum recommended input capacitance for MP28255EL-LF-Z?

A 22μF X5R/X7R ceramic capacitor is the minimum recommended input capacitance, placed as close as possible to the IN and GND pins. This value ensures adequate RMS current handling (≥2A) and limits input voltage ripple to <100mV_pp at full 4A load, per MPS Application Note AN-103.

Can MP28255EL-LF-Z operate with an output voltage lower than 0.8V?

No-the internal feedback reference is fixed at 0.805V ±1.5%, and the device is not specified or characterized for output voltages below 0.8V. Attempting sub-0.8V operation results in loss of regulation and potential instability due to error amplifier saturation.

How does the EN/SYNC pin function in synchronization mode?

In sync mode, the EN/SYNC pin accepts an external 300kHz–2MHz clock signal. The internal oscillator locks to the rising edge of this signal, ensuring deterministic switching phase alignment across multiple converters-critical for reducing beat-frequency EMI in multi-phase systems.

Is an external bootstrap diode required for reliable operation?

An external bootstrap diode (e.g., IN4148) is optional but recommended when duty cycle exceeds 65% (V_OUT/V_IN > 0.65), such as in 3.3V-out-from-12V-in applications. It improves BST capacitor charging efficiency and prevents high-side FET turn-off delay during heavy load transients.

What is the maximum allowable output capacitor ESR for stable operation?

The MP28255EL-LF-Z supports output capacitors with ESR up to 20mΩ when using ceramic types, and up to 50mΩ for tantalum/electrolytic types. Stability is maintained across 10μF–100μF total C_OUT, as verified in MPS AN-102 with 47μF X5R ceramic + 0.1μF NP0 parallel configuration.

Does MP28255EL-LF-Z support forced PWM mode at light load?

No-it operates exclusively in peak-current-mode with automatic pulse-skipping at light loads to maintain high efficiency. There is no pin or register to force continuous conduction mode (CCM); light-load efficiency peaks at >85% due to quiescent current of 0.7mA.

How is thermal performance affected by the exposed pad soldering?

Full solder coverage of the exposed thermal pad to a solid GND plane reduces θ_JA from 65°C/W (no pad connection) to 48°C/W. Inadequate pad soldering increases junction temperature by ≥15°C at 4A, risking premature thermal shutdown and reduced reliability.

MP28255EL-LF-Z Specifications

Product attributes: Attribute value

Manufacturer:: Monolithic Power Systems Inc.

Series:: -

Package/Case:: 14-VFDFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Not For New Designs

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 4.5V

Voltage - Input (Max):: 21V

Voltage - Output (Min/Fixed):: 0.8V

Voltage - Output (Max):: 5V

Current - Output:: 4A

Frequency - Switching:: 500kHz

Synchronous Rectifier:: No

Operating Temperature:: -20°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-QFN (3x4)

MP28255EL-LF-Z FAQ

1.How can I place an order for MP28255EL-LF-Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MP28255EL-LF-Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MP28255EL-LF-Z reliable?

The price and inventory of MP28255EL-LF-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP28255EL-LF-Z is usually 5 days.

3.What payment methods are accepted for MP28255EL-LF-Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP28255EL-LF-Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MP28255EL-LF-Z?

MP28255EL-LF-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MP28255EL-LF-Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MP28255EL-LF-Z?

For technical support, including MP28255EL-LF-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP28255EL-LF-Z requirements.

6.How does Aetrix verify that MP28255EL-LF-Z is sourced from the original manufacturer or authorized distributors?

All MP28255EL-LF-Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MP28255EL-LF-Z meets industry standards.

7.What is the process for return or replacement of MP28255EL-LF-Z?

All MP28255EL-LF-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP28255EL-LF-Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MP28255EL-LF-Z part is unused and in its original packaging.

Return procedure for MP28255EL-LF-Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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