Monolithic Power Systems Inc. MP38872DL-LF-Z

Overview

MP38872DL-LF-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter with integrated 45mΩ high-side MOSFET and external low-side gate driver, delivering 6A continuous output current across 4.5V–21V input range. It operates at fixed 600kHz switching frequency, supports external synchronization up to 1.5MHz, and features power-good indication, cycle-by-cycle over-current protection, and thermal shutdown-used in flat-panel TV power rails and digital set-top box point-of-load regulation.

For engineers reviewing the MP38872DL-LF-Z datasheet, MP38872DL-LF-Z pinout, MP38872DL-LF-Z application, or MP38872DL-LF-Z equivalent, key selection criteria include its synchronizable gate driver architecture, 0.8V adjustable output voltage reference, 100ns minimum on-time, and QFN-14 (3×4mm) thermally enhanced package with exposed pad.

Technical Context

The MP38872DL-LF-Z implements peak-current-mode control with a fixed 600kHz oscillator and internal 0.808V feedback reference. Its error amplifier drives a COMP node that sets MOSFET peak current, while the EN/SYNC pin serves dual function: logic-level enable and external clock synchronization via rising-edge alignment.

It integrates a 5V internal VCC regulator powered from VIN, biasing the high-side driver and error amplifier; the floating BG driver requires external bootstrap capacitor (BST–SW) and supports gate drive source/sink impedances of 4Ω/1Ω. Thermal shutdown triggers at 150°C with 10°C hysteresis, and hiccup-mode over-current protection activates when FB falls below 250mV.

Key Specifications

Pinout & Package

MP38872DL-LF-Z is housed in a thermally enhanced 14-pin QFN package (3mm × 4mm) with exposed thermal pad on underside, optimized for PCB heat dissipation in high-current applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2315DJ-LF-Z and RT7297BZSP, the MP38872DL-LF-Z uniquely combines 6A capability, external MOSFET control for optimal efficiency tuning, and full-frequency synchronization-making it the only choice for noise-sensitive, multi-rail, high-current embedded systems requiring deterministic timing alignment.

Availability

MP38872DL-LF-Z is available at Aetrix Electronics and suitable for flat panel television power rails, digital set-top box core supplies, and broadband communications gateway designs requiring stable component supply, RoHS-compliant packaging, and extended temperature operation (–40°C to +85°C).

Supply support for MP38872DL-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 MP38872 belongs to MPS's high-current synchronous buck converter product line, engineered for distributed power architectures in consumer electronics where efficiency, thermal performance, and EMI control are critical.

FAQ

What is the minimum recommended output capacitance for stable operation?

The MP38872DL-LF-Z is stable with low-ESR ceramic capacitors; a minimum of 100µF total output capacitance (e.g., one 100µF/6.3V X5R or two 47µF in parallel) is required to maintain loop stability and limit output ripple under 6A load transients. The datasheet validates stability with 100µF at the VOUT node.

Can the MP38872DL-LF-Z operate without an external synchronous MOSFET?

No-it requires an external low-side MOSFET connected to the BG pin; the internal high-side switch alone cannot complete the buck power stage. Omitting the external FET prevents proper inductor current freewheeling and will cause immediate failure or no regulation.

How does the EN/SYNC pin behave during external clock synchronization?

When an external clock (300kHz–1.5MHz) is applied to EN/SYNC, the internal 600kHz oscillator locks to its rising edge-enabling deterministic phase alignment across multiple converters. The pin remains functional as an enable input: pulling it below 0.4V disables the IC regardless of clock presence.

What thermal derating applies above +85°C ambient?

The device is rated for operation up to +85°C ambient; junction temperature must not exceed +125°C. With θJA = 48°C/W on a 4-layer PCB, power dissipation must be limited to ≤(125−TA)/48 W. At TA = 100°C, operation is not guaranteed-thermal shutdown activates at TJ = 150°C.

Is the BST capacitor mandatory, and what value is recommended?

Yes-the BST capacitor between BST and SW pins is mandatory to generate the floating supply for the high-side gate driver. A 1µF X7R/X5R ceramic capacitor rated ≥16V is specified; values below 0.47µF risk insufficient charge hold and driver dropout during high-duty-cycle operation.

Does the MP38872DL-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 efficiency. There is no pin or register to force continuous conduction mode (CCM); the hiccup and foldback behaviors are inherent to its protection architecture.

What is the maximum allowable input voltage transient?

The absolute maximum VIN rating is 23V; transients exceeding this-even for <10ns-risk permanent damage. Input capacitors and layout must suppress spikes; the datasheet specifies that 23V is the hard clamp, not a recommended operating limit.