Monolithic Power Systems Inc. MP38892DN-LF-P

Overview

MP38892DN-LF-P from Monolithic Power Systems is a synchronous step-down DC/DC converter with integrated 100mΩ high-side MOSFET and external gate driver for low-side FET control. It delivers 6A continuous output current from 4.5V–42V input, features fixed 420kHz switching frequency (synchronizable to 300kHz–1.5MHz), ±1.5% V_FB accuracy, and thermal shutdown protection. Used in flat-panel TV power rails requiring high efficiency and compact layout.

For engineers reviewing the MP38892DN-LF-P datasheet, MP38892DN-LF-P pinout, MP38892DN-LF-P application, or MP38892DN-LF-P equivalent, key selection criteria include input voltage range compatibility, external synchronous FET drive capability, bootstrap capacitor requirements, and thermal performance in SOIC8E exposed-pad packages.

Technical Context

The MP38892DN-LF-P implements peak-current-mode control with internal 0.8V reference and error amplifier driving COMP node for loop stability. Its oscillator operates at fixed 420kHz but accepts external sync signals up to 1.5MHz via EN/SYNC pin, enabling noise-sensitive system clock alignment.

It integrates a 5V internal regulator (V_CC) powered from VIN, supplying bias to the floating gate driver; the bootstrap circuit charges via SW–BST diode path and supports external BST diode (e.g., IN4148) when duty cycle exceeds 65% for improved efficiency at 3.3V/5V outputs.

Key Specifications

Pinout & Package

The MP38892DN-LF-P is housed in an 8-pin SOIC package with exposed thermal pad (SOIC8E), optimized for PCB heat dissipation (θ_JA = 50°C/W on 4-layer board). The exposed pad must be soldered to GND plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ38892-AEC1, the MP38892DN-LF-P offers identical electrical specs but lacks automotive qualification and higher-temp operation; versus MP2332HG-A, it trades integration for wider input range, higher current, and external FET control-critical for thermal optimization in high-power TV/STB designs.

Availability

MP38892DN-LF-P is available at Aetrix Electronics and suitable for digital set-top boxes, personal video recorders, and broadband communications gateways requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP38892DN-LF-P 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 MP38892 belongs to MPS's high-current synchronous buck converter product line, designed specifically for mid-power applications demanding wide input range, external FET flexibility, and precise thermal management in space-constrained enclosures.

FAQ

What is the minimum input voltage required for reliable startup?

The MP38892DN-LF-P has an under-voltage lockout (UVLO) rising threshold of 4.10V with 880mV hysteresis. Reliable startup occurs only when VIN exceeds 4.10V; operation below 3.2V causes automatic shutdown. This ensures stable reference and regulator initialization before gate drive activation.

Can the MP38892DN-LF-P operate without an external synchronous MOSFET?

No. The MP38892DN-LF-P integrates only a high-side MOSFET and requires an external low-side MOSFET driven by the BG pin. It cannot function as a standalone buck converter without this external FET, as there is no internal body diode or freewheeling path.

How does the bootstrap capacitor value affect performance?

A 0.1–1µF ceramic capacitor between BST and SW is mandatory for proper gate drive. Values <0.1µF risk insufficient charge hold during high-duty-cycle operation, causing gate drive collapse and increased conduction loss; values >1µF delay startup but improve stability under heavy load transients.

Is an external bootstrap diode required for all applications?

An external bootstrap diode (e.g., IN4148) is optional and recommended only when V_OUT = 3.3V or 5V and duty cycle exceeds 65% (i.e., V_IN/V_OUT > 1.5). It improves BST capacitor charging efficiency and reduces thermal stress on the internal bootstrap diode.

What is the purpose of the exposed thermal pad, and how must it be connected?

The exposed pad serves as both thermal dissipation path and primary GND connection. It must be soldered to a dedicated PCB copper pour tied directly to the main GND plane-no thermal relief-to achieve θ_JA = 50°C/W and prevent thermal shutdown under 6A continuous load.

Does the MP38892DN-LF-P support light-load efficiency optimization modes?

No. The MP38892DN-LF-P operates exclusively in forced continuous conduction mode (CCM) at fixed frequency. It does not feature pulse-skipping, burst mode, or discontinuous conduction mode (DCM) - ensuring predictable EMI but limiting light-load efficiency compared to adaptive-mode converters.

How is output voltage adjusted, and what tolerance does the feedback network introduce?

Output voltage is set by an external resistor divider from V_OUT to GND, with FB connected to the midpoint. With ±1.5% V_FB accuracy and 1% resistor tolerances, total output error remains within ±3.5% - sufficient for non-precision digital rails but not for analog-sensitive applications.