Monolithic Power Systems Inc. MP3438GTL-P

Overview

MP3438GTL-P from Monolithic Power Systems is a fully integrated, synchronous boost converter IC with 2A switching current limit, 1.2MHz fixed-frequency COT control, and automatic pass-through mode. It operates from 0.8V to 16V input, delivers up to 16V output, and integrates low-R_DS(ON) HS/LS MOSFETs in an SOT583 package. Used in portable instrumentation and LCD bias supplies where high efficiency at light load and fast transient response are critical.

For engineers reviewing the MP3438GTL-P datasheet, MP3438GTL-P pinout, MP3438GTL-P application, or MP3438GTL-P equivalent, key selection factors include its adaptive COT control architecture, 2.7V startup capability, configurable VIN UVLO via EN pin, and integrated soft-start with internal compensation - all verified in production-grade electrical characterization across –40°C to +125°C.

Technical Context

The MP3438GTL-P implements constant-off-time (COT) control with cycle-by-cycle current limiting on the low-side MOSFET and automatic pass-through mode when VIN exceeds VOUT-SET. Its internal 1V reference voltage (±0.5% over temperature) feeds an error amplifier that drives PWM comparator logic, while BST pin supplies 3.2V gate drive for the high-side MOSFET during boost operation.

Thermal shutdown activates at 150°C with 25°C hysteresis, and over-voltage protection triggers at 110% of VREF on the FB pin. The EN pin supports micro-power mode (1V threshold), full enable (1.2V), and configurable VIN UVLO hysteresis using external resistors - enabling precise system-level power sequencing without external supervisors.

Key Specifications

Pinout & Package

The MP3438GTL-P is housed in a thermally enhanced SOT583 package (1.6mm × 2.1mm, 0.5mm pitch), optimized for high-density portable PCB layouts and thermal performance (θ_JA = 65°C/W on 2-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS61088RHLR and RT9086AGQW, the MP3438GTL-P uniquely combines 16V input tolerance, 2A current capability, adaptive COT control, and automatic pass-through - making it optimal for high-efficiency, wide-input portable systems requiring dynamic voltage scaling and minimal BOM count.

Availability

MP3438GTL-P is available at Aetrix Electronics and suitable for LCD bias supplies, portable instrumentation, DSL line drivers, and electronic cigarette power management requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP3438GTL-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 power management ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP3438 belongs to MPS's high-efficiency synchronous boost converter product line, engineered for space-constrained, battery-powered applications demanding wide input range, fast transient response, and minimal external component count.

FAQ

What is the minimum input voltage required for reliable startup?

The MP3438GTL-P starts reliably from 2.7V when powered through VIN with EN tied high. If an external VCC bias ≥0.9V is applied, startup occurs at VIN as low as 0.9V. Below 2.7V, VCC may not reach its 2.2–2.6V UVLO rising threshold, preventing switching initiation.

How does automatic pass-through mode improve system efficiency?

When VIN exceeds the programmed VOUT-SET, the MP3438GTL-P disables switching and turns on the high-side MOSFET continuously, eliminating switching losses and gate drive energy. This achieves >95% efficiency - versus ~85% in boost mode - while maintaining regulation via the internal charge pump driving BST.

Can the MP3438GTL-P be used without an external inductor?

No. The MP3438GTL-P requires an external power inductor (e.g., MPS MPL-AL4020-3R3) connected between SW and VIN. The inductor stores energy during LS-FET conduction and transfers it to the output during HS-FET conduction; omitting it causes immediate overcurrent fault and device shutdown.

What is the purpose of the BST pin, and how should it be decoupled?

The BST pin supplies gate drive voltage (~3.2V above SW) to the high-side MOSFET. It must be decoupled with a 0.1μF ceramic capacitor between BST and SW. This capacitor charges from VCC during LS-FET on-time and discharges to drive the HS-FET gate - improper sizing causes shoot-through or weak turn-on.

Does the MP3438GTL-P support output over-voltage protection?

Yes. The FB pin has over-voltage protection that triggers when VFB exceeds 110% of the 1V reference (i.e., 1.1V). At that point, the LS-FET is disabled until VFB falls below 105% (1.05V), preventing damage to downstream 5V or 3.3V logic from feedback divider failure or open-circuit conditions.

How is the output voltage set, and what resistor tolerance is recommended?

VOUT is set by a resistor divider from VOUT to FB: R2 = R1 × (VREF / (VOUT − VREF)), where VREF = 1.00V. Use 1% tolerance metal-film or thin-film resistors for R1 (100kΩ–1MΩ) and R2 to maintain ≤1.5% output error across temperature and process variation.

What thermal derating applies above 25°C ambient?

With θ_JA = 65°C/W on a 2-layer 51mm×51mm PCB, the MP3438GTL-P dissipates up to 1.9W at 25°C. At 85°C ambient, maximum continuous power drops to (150°C − 85°C) / 65°C/W = 1.0W. Thermal shutdown activates at 150°C junction, with recovery at 125°C.