Monolithic Power Systems Inc. MP38876DL-LF-P

Overview

MP38876DL-LF-P from Monolithic Power Systems is a monolithic synchronous step-down DC-DC converter with integrated 25mΩ high-side MOSFET and external gate driver for low-side synchronous rectification. It delivers 15A continuous output current from 4.5V–28V input, supports 0.8V–12V adjustable output, and operates at fixed 400kHz or externally synchronized 300kHz–1MHz. It is used in space-constrained PCBs requiring high-current pre-regulation, such as server VRMs and telecom power modules.

For engineers reviewing the MP38876DL-LF-P datasheet, MP38876DL-LF-P pinout, MP38876DL-LF-P application, or MP38876DL-LF-P equivalent, key selection criteria include its 15A output capability, synchronous gate drive architecture, phase-shift synchronization support via SYNCIN/SYNCOUT, and thermal shutdown at 150°C - all critical for high-density, multi-phase power delivery designs.

Technical Context

The MP38876DL-LF-P uses peak current-mode control with a fixed 400kHz oscillator or external synchronization up to 1MHz, enabling precise interleaving across multiple phases. Its internal 25mΩ high-side switch and dedicated GATE pin drive an external low-side MOSFET, forming a fully synchronous buck topology optimized for efficiency above 90% at 12V_IN/1.2V_OUT/15A.

It integrates cycle-by-cycle overcurrent protection triggered by FB voltage collapse below 400mV, programmable soft-start via SS/TRK pin, and power-good monitoring with 20μs delay and ±5% regulation window. The bootstrap (BST) circuit sustains floating gate drive with non-overlap timing (10ns T_d1/T_d2) to prevent shoot-through.

Key Specifications

Pinout & Package

MP38876DL-LF-P is housed in a thermally enhanced 20-pin 3mm × 4mm QFN package with exposed thermal pad (Pin 10/18). The package supports high-current routing via fused SW pins (11–17) and dual VIN inputs (10, 18), while minimizing footprint in space-limited applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP38876DL-LF-P, MPQ3426-AEC1 trades 15A capability and SYNCOUT functionality for automotive qualification, while LM5143A-Q1 extends input voltage range but increases design complexity by omitting the dedicated GATE driver - making MP38876DL-LF-P optimal for high-current, space-constrained, multi-phase industrial and telecom applications.

Availability

MP38876DL-LF-P is available at Aetrix Electronics and suitable for server VRMs, telecom baseband power supplies, and industrial PLC I/O modules requiring stable component supply across extended temperature and high-reliability production cycles.

Supply support for MP38876DL-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, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP38876 belongs to MPS's high-current synchronous buck converter product line, engineered for compact, high-efficiency power delivery in datacenter, networking, and industrial equipment where thermal density and multi-phase scalability are critical.

FAQ

What is the maximum supported switching frequency when using external synchronization?

The MP38876DL-LF-P accepts external clock signals from 300kHz to greater than 1MHz on the SYNCIN pin, with guaranteed operation up to 1MHz. Performance remains stable across this range, and the internal oscillator is disabled when SYNCIN voltage exceeds 2V, enabling precise EMI management and multi-phase interleaving.

Can the MP38876DL-LF-P operate without an external low-side MOSFET?

No. The MP38876DL-LF-P integrates only a high-side MOSFET (25mΩ R_DS(on)) and requires an external low-side MOSFET driven by the GATE pin. It does not support diode rectification - attempting to operate without the external MOSFET will result in failure to regulate output voltage.

How does the SS/TRK pin function during power-up and tracking modes?

The SS/TRK pin serves dual roles: as a soft-start capacitor connection (0–1.2V ramp) to limit inrush current, or as a tracking input where an external voltage source overrides the internal reference to force output voltage to follow another rail's ramp profile - both functions are enabled simultaneously without mode selection.

What is the purpose of the BST pin and required external components?

The BST pin connects to the SW node via a 0.1µF–1µF ceramic capacitor to form a bootstrap supply that elevates the high-side gate driver above VIN. This floating voltage enables full enhancement of the internal N-channel MOSFET; omission causes immediate undervoltage lockout of the gate driver.

Does the MP38876DL-LF-P support output voltage adjustment below 0.8V?

No. The internal reference is fixed at 0.8V, and the feedback comparator is designed for minimum 0.8V output. Attempting to set V_OUT lower via resistor divider violates the FB pin's operational specification and results in unstable regulation or failure to start.

How is thermal performance affected by the exposed pad connection?

The exposed thermal pad (Pins 10/18) must be soldered to a minimum 100mm² copper pour with ≥4 thermal vias to internal ground planes. Without this, θ_JA degrades from 48°C/W to >75°C/W, causing premature thermal shutdown at ≤8A load even at 25°C ambient.

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

Upon output short, FB voltage collapses below 400mV, triggering oscillator foldback to 100kHz and reducing peak current. If FB remains below 50% of reference while soft-start completes, the device latches off until EN or VIN is cycled - preventing thermal runaway and enabling safe auto-recovery after fault removal.