Monolithic Power Systems Inc. MP3308DL-LF-Z

Overview

MP3308DL-LF-Z from Monolithic Power Systems is a fixed-frequency current-mode step-up white LED driver IC with integrated 1.3A MOSFET, designed to drive up to 10 series-connected white LEDs from 2.5–6V input (e.g., single-cell Li-ion). It delivers true PWM dimming with ±3% duty accuracy, 200mV ISET feedback voltage, and dual independent PWM inputs (PWMIA/PWMIB) for flexible backlight luminance control in portable displays.

For engineers reviewing the MP3308DL-LF-Z datasheet, MP3308DL-LF-Z pinout, MP3308DL-LF-Z application, or MP3308DL-LF-Z equivalent, key selection criteria include its 2.2MHz switching frequency, adjustable over-voltage protection via OVP pin, thermal/short-circuit/UVLO protections, and QFN14 (3×4mm) package with exposed thermal pad tied to PGND.

Technical Context

The MP3308DL-LF-Z implements a constant-frequency peak-current-mode boost architecture with internal error amplifier comparing 200mV ISET reference against sensed current. Its dual PWM dimming path processes independent signals on PWMIA and PWMIB, filtered internally to PWMOA/PWMOB outputs using external RC networks, enabling multiplicative brightness control (D_PWMA × D_PWMB).

OVP threshold is set externally via resistor divider on OVP pin (trip at 0.9V), while FSET pin programs PWM dimming frequency (f_PWM = 16176 / C_FSET(nF)) across 50Hz–50kHz range. Protection includes short-circuit detection via ISET pin voltage >0.4V for >240µs, thermal shutdown at 150°C, and UVLO with 2.3V turn-on and 30mV hysteresis.

Key Specifications

Pinout & Package

MP3308DL-LF-Z is housed in a thermally enhanced 3mm × 4mm, 14-pin QFN package with exposed PGND pad on underside requiring solder connection to PCB ground plane for optimal thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar white LED driver applications.

Compared with RT8532GQW and TPS61165DRVR, MP3308DL-LF-Z uniquely integrates dual PWM processing, adjustable OVP, and 200mV ISET in a 3×4mm QFN - optimizing for compact, flicker-free, thermally constrained portable displays.

Availability

MP3308DL-LF-Z is available at Aetrix Electronics and suitable for smartphone displays, digital picture frames, and small LCD panels requiring stable component supply, RoHS-compliant packaging, and production-ready lead times.

Supply support for MP3308DL-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 U.S.-based analog and mixed-signal semiconductor company specializing in high-efficiency power management ICs for consumer, industrial, and automotive markets.

The MP3308 belongs to MPS's white LED driver product line, engineered specifically for space-constrained portable displays requiring high dimming fidelity, low quiescent current, and robust fault protection without external power switches.

FAQ

What is the maximum number of white LEDs the MP3308DL-LF-Z can drive in series?

The MP3308DL-LF-Z supports up to 10 white LEDs in series, assuming typical forward voltage of 3.0–3.6V per LED and maximum output voltage of 36V at SW pin. At 3.3V input, it achieves ~9–10 LEDs depending on LED V_F variation and efficiency losses. The datasheet confirms this limit under "Features" and "Typical Application" sections.

How does dual PWM dimming work on the MP3308DL-LF-Z?

Dual PWM dimming uses two independent inputs (PWMIA and PWMIB) whose duty cycles are internally multiplied to generate effective dimming level: D_eff = D_PWMA × D_PWMB. This enables >10,000:1 dimming range without analog control noise or color shift. External capacitors on PWMOA/PWMOB pins filter each signal into DC control voltages.

Can the MP3308DL-LF-Z operate from a 3.3V supply?

Yes - the MP3308DL-LF-Z operates from 2.5V to 6V input, making it fully compatible with standard 3.3V rails and single-cell Li-ion batteries (2.8–4.2V). Its 2.2MHz switching frequency and low 200mV ISET reference ensure high efficiency even at low input voltages.

What is the purpose of the FSET pin?

The FSET pin sets the PWM dimming frequency using an external capacitor: f_PWM = 16176 / C_FSET(nF). A 10nF capacitor yields ~1.6kHz, within the recommended 50Hz–50kHz range. This allows designers to avoid audible noise while maintaining smooth dimming response and minimizing capacitor size.

Does the MP3308DL-LF-Z require an external Schottky diode?

Yes - the MP3308DL-LF-Z uses external asynchronous rectification. A Schottky diode (e.g., B0530) must be placed between SW and VOUT to complete the boost power path. The datasheet specifies fast-recovery Schottky diodes rated for ≥500mA peak inductor current and low forward voltage to maintain efficiency.

How is over-voltage protection configured?

OVP is configured using a resistor divider from VOUT to GND, with the midpoint connected to the OVP pin. The MP3308 triggers shutdown when OVP pin voltage reaches 0.9V, so threshold is set by V_OVP = 0.9V × (1 + R_top/R_bottom). Typical values (e.g., 160kΩ/10kΩ) yield ~15.3V clamp for 9-string LED arrays.

What thermal considerations apply to the QFN14 package?

The QFN14 (3×4mm) package features an exposed PGND pad that must be soldered to a large PCB copper pour for thermal conduction. θ_JA is 48°C/W on a 4-layer board; exceeding 2.6W continuous power dissipation risks thermal shutdown. Layout guidelines emphasize short SW–diode–capacitor loop and direct PGND pad connection to minimize junction temperature rise.