Monolithic Power Systems Inc. MP3115DT-LF-P

Overview

MP3115DT-LF-P from Monolithic Power Systems is a synchronous, fixed-frequency (1.3MHz), current-mode step-up DC-DC converter optimized for single-cell alkaline battery input (0.95V startup) to regulated 2.5V/3.3V/4.0V output up to 200mA, featuring integrated P-channel and N-channel MOSFETs, output-to-input disconnect, and internal compensation in SOT23-6 package. It delivers >90% efficiency and supports consumer portable devices with strict shutdown current (<1µA) and inrush limiting.

For engineers reviewing the MP3115DT-LF-P datasheet, MP3115DT-LF-P pinout, MP3115DT-LF-P application, or MP3115DT-LF-P equivalent, key selection criteria include minimum startup voltage (0.95V), output disconnect capability, 1.3MHz switching frequency for compact magnetics, internal soft-start, and thermal shutdown at 160°C - all critical for low-power battery-operated systems.

Technical Context

The MP3115 employs a fixed-frequency (1.3MHz) current-mode control architecture with internal 1.2V reference and error amplifier, enabling fast transient response and stable regulation across load and input variations. Its dual-MOSFET topology integrates a 300mΩ NMOS switch and 600mΩ PMOS rectifier, eliminating external Schottky diodes while supporting output disconnect via PMOS body-diode isolation during shutdown.

Startup occurs down to 0.95V input with inrush limiting; regulation maintains ±2% output accuracy over temperature (–40°C to +85°C) using external resistive feedback. Thermal shutdown (160°C, 30°C hysteresis) and 1A peak current limit provide robust protection without external components.

Key Specifications

Pinout & Package

MP3115DT-LF-P is housed in a thermally enhanced 6-pin SOT23-6 package (JEDEC MO-178AA), with exposed pad not electrically connected. Pin spacing is 0.95mm, footprint compatible with standard SOT23 reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP3414DT-LF-Z, MP3115DT-LF-P offers proven reliability in high-volume consumer products but trades off peak current and startup voltage; versus TPS61200DRCR, it delivers superior integration (no external diode) and true output isolation - critical for long-term battery retention in infrequently used devices.

Availability

MP3115DT-LF-P is available at Aetrix Electronics and suitable for wireless peripherals, portable audio devices, rugged RFID tags, and low-power remote controls requiring stable component supply and long-lifecycle support.

Supply support for MP3115DT-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, serving industrial, automotive, and consumer markets since 1997.

The MP3115 belongs to MPS's low-voltage DC-DC boost converter product line, engineered specifically for energy-constrained, single-cell battery applications where startup voltage, shutdown current, and integration density are primary constraints.

FAQ

What is the minimum input voltage required to start up the MP3115DT-LF-P?

The MP3115DT-LF-P guarantees startup from 0.95V (typical 1.1V) with a 3kΩ load on the output. This enables operation down to the final usable voltage of a single alkaline AA/AAA cell, extending effective battery life significantly compared to converters requiring ≥1.2V startup.

Does the MP3115DT-LF-P require an external Schottky diode?

No. The MP3115DT-LF-P integrates both NMOS and PMOS power switches, enabling fully synchronous rectification. This eliminates the need for an external Schottky diode, reducing bill-of-materials cost, PCB area, and conduction losses - improving efficiency by up to 12% at light loads.

How does the output disconnect feature function during shutdown?

When EN is pulled low (<0.4V), the internal PMOS gate is driven to isolate the OUT pin from the SW node. This breaks the path between output capacitor and input source, allowing the output to fully discharge and reducing total shutdown current to <1µA - essential for zero-drain standby in battery-critical applications.

Can the MP3115DT-LF-P regulate output voltages above 3.3V?

Yes. The MP3115DT-LF-P supports output voltages from 2.5V to 4.0V, set by an external resistive divider on the FB pin. For 4.0V output, use R1 = 46.4kΩ with R2 = 20kΩ (based on 1.225V reference), enabling compatibility with 3.6V–4.2V logic interfaces or white LED biasing.

What is the recommended inductor value for typical MP3115DT-LF-P applications?

MPS recommends a 4.7µH shielded power inductor rated for ≥1.5A saturation current. This value balances peak-to-peak ripple current (~40% of max load), size, and efficiency across 0.95–1.5V input range. Inductor DCR should be <150mΩ to minimize conduction loss.

Is thermal shutdown active during normal operation or only under fault conditions?

Thermal shutdown activates only under sustained overload, poor PCB thermal design, or ambient temperatures exceeding +85°C. The 160°C trip point (with 30°C hysteresis) is designed to protect against catastrophic failure - not routine operation - and automatically recovers once die temperature falls below 130°C.

What is the maximum continuous output current achievable with MP3115DT-LF-P?

At 3.3V output and 1.5V input, the MP3115DT-LF-P delivers up to 200mA continuously with >90% efficiency. Output current is limited by thermal dissipation in the SOT23-6 package and the 1A peak switch current limit - higher currents require careful thermal management or forced airflow.