Monolithic Power Systems Inc. MP2565DN-LF

Overview

MP2565DN-LF from Monolithic Power Systems is a non-synchronous step-down DC/DC converter with integrated 220mΩ high-side MOSFET, delivering up to 2.5A output current across a 4.5V–50V input range and supporting adjustable output voltages from 0.8V to 47V. It operates at up to 4MHz switching frequency, features current-mode control for fast transient response, and includes internal soft-start, thermal shutdown, and programmable frequency via external resistor. It is used in automotive power rails where wide VIN and EMI-sensitive environments (e.g., AM radio band) demand high-frequency operation.

For engineers reviewing the MP2565DN-LF datasheet, MP2565DN-LF pinout, MP2565DN-LF application, or MP2565DN-LF equivalent, key selection criteria include its 50V max input rating, 12µA shutdown current for battery systems, 4MHz programmability to avoid interference bands, SOIC8E thermally enhanced package, and internal current limit without external sense resistor.

Technical Context

The MP2565DN-LF employs variable-frequency current-mode PWM control with cycle-by-cycle peak current limiting and blanking during switch turn-on to suppress noise-induced false triggering. Its error amplifier delivers 200V/V gain and 60µA/V transconductance, driving an external RC compensation network on the COMP pin to stabilize the loop across ceramic-output-capacitor configurations.

Startup uses an internal soft-start ramp (1.3ms typical) that overrides the 0.8V reference until settled; shutdown is triggered by EN <1.3V, VIN UVLO (<2.7V), or junction temperature >150°C with 15°C hysteresis. Bootstrap charging relies on external BST–SW capacitor and requires sufficient VIN–VOUT headroom during diode conduction phase.

Key Specifications

Pinout & Package

MP2565DN-LF is housed in a thermally enhanced SOIC-8 package with exposed pad (SOIC8E), requiring solder connection of the exposed pad to PCB ground plane for optimal thermal performance (θ_JC = 10°C/W). Pin numbering follows standard SOIC top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5164QDDARQ1 and TPS54560QDGQRQ1, MP2565DN-LF offers superior integration (no external FET/sense resistor), higher switching frequency for EMI-sensitive designs, and lower quiescent current - making it optimal for compact, battery-aware, and 48V-compatible applications where 2.5A output is sufficient.

Availability

MP2565DN-LF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial 24V-to-5V conversion, and battery-powered telematics requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP2565DN-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, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP2565 belongs to MPS's high-voltage DC/DC converter product line, engineered for automotive, industrial, and telecom applications demanding wide input range, high frequency, and robust thermal performance in compact packages.

FAQ

What is the maximum allowable input voltage for MP2565DN-LF, and what happens above that limit?

The absolute maximum input voltage is +55V. Operation above 50V violates the recommended operating condition and risks permanent damage due to overstress of the internal high-side MOSFET and gate driver circuitry. The device includes VIN UVLO (rising threshold 3.0V, hysteresis 0.4V) but no overvoltage protection - external clamping or TVS is required for load-dump transients exceeding 50V.

Can MP2565DN-LF operate with only ceramic output capacitors, and what is the minimum recommended value?

Yes, MP2565DN-LF is explicitly designed for stability with ceramic output capacitors. The datasheet confirms stable operation with 22µF X5R/X7R MLCCs. Minimum recommended value is 10µF for 3.3V/2.5A operation; lower values may compromise transient response and increase output ripple, especially under 2A load steps.

How is the switching frequency set, and what resistor value yields exactly 4MHz?

Frequency is set by connecting a resistor (R_FREQ) from the FREQ pin to GND. For 4MHz, use R_FREQ = 18kΩ (typical), based on the formula f_SW(kHz) = 180000 / R_FREQ(kΩ). Measured frequency tolerance is ±20% due to process variation; actual frequency at 18kΩ ranges from 3.2MHz to 4.8MHz per electrical characteristics table.

Does MP2565DN-LF require an external bootstrap diode, and why or why not?

No external bootstrap diode is required. The MP2565DN-LF integrates a dedicated bootstrap regulator that charges the BST–SW capacitor from VIN during low-side conduction. An external diode is only recommended in high-duty-cycle (>90%) applications where bootstrap capacitor recharge time is insufficient - not needed for standard 3.3V/5V/12V outputs.

What is the purpose of the exposed pad on the SOIC8E package, and how must it be connected?

The exposed pad is electrically and thermally connected to GND. It must be soldered to a PCB copper pour tied to the main ground plane to achieve θ_JC = 10°C/W and prevent thermal shutdown under full load. Leaving it unconnected increases junction temperature by >30°C at 2.5A and risks premature thermal limiting.

How does the MP2565DN-LF handle light-load efficiency, and what mechanism enables it?

It uses frequency foldback: switching frequency scales downward under light load to reduce gate-driving and switching losses. At 10mA output, frequency drops to ~500kHz, maintaining >85% efficiency - unlike fixed-frequency converters that suffer disproportionate losses below 10% load.

Is the FB pin biased, and how does that affect resistor divider design?

Yes, the FB pin draws 20µA of current from the divider's bottom resistor (R2). To minimize voltage error, R2 must be ≤40.2kΩ (e.g., 40.2kΩ standard value). For a 3.3V output, R1 = 127kΩ ensures V_FB = 0.8V despite this current sink, per the equation V_OUT = 0.8V × (1 + R1/R2).