Monolithic Power Systems Inc. MP3384EQ-LF-P

Overview

MP3384EQ-LF-P from Monolithic Power Systems is a 4-channel white LED driver IC with integrated step-up converter, designed for large LCD panel backlighting. It delivers up to 50V output from 4.5–25V input, regulates four independent LED strings with 2.5% current matching accuracy, and supports selectable 1.25MHz/625kHz switching frequency. Used in notebook PC and automotive display systems requiring precise multi-string current control.

For engineers reviewing the MP3384EQ-LF-P datasheet, MP3384EQ-LF-P pinout, MP3384EQ-LF-P application, or MP3384EQ-LF-P equivalent, key selection criteria include its 600mV LED current-sense voltage, open/short LED protection architecture, PWM dimming interface, and QFN16 (3mm × 3mm) thermal performance with exposed PGND pad.

Technical Context

The MP3384EQ-LF-P integrates a fixed-frequency peak-current-mode boost controller with four matched internal current sinks. Its regulation loop uses a 600mV reference at each LEDX pin to maintain string current, while COMP pin enables loop compensation via external RC network. The device selects boost frequency via OSC pin logic level-GND for 625kHz, floating/VCC for 1.25MHz.

Protection functions are tightly coupled to analog monitoring: OVP pin senses output overvoltage via resistor divider (trip threshold 1.23V), LEDX pins detect open/short faults by voltage thresholds (180mV UVLO, 5.5V OV), and thermal shutdown activates at 150°C. VCC is an internal 5V LDO powered from VIN >5.5V, otherwise requires external bias.

Key Specifications

Pinout & Package

MP3384EQ-LF-P is housed in a thermally enhanced QFN16 package (3mm × 3mm, 0.5mm pitch) with exposed PGND pad soldered to PCB for optimal thermal dissipation. Pin 12 (PGND) connects directly to the exposed pad, which must be tied to system power ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RT9397B-ZSP and LM3409QMY/NOPB, MP3384EQ-LF-P provides tighter current matching (2.5% vs 5%), integrated VCC LDO, and autonomous string fault handling - reducing validation effort for consumer and automotive display programs.

Availability

MP3384EQ-LF-P is available at Aetrix Electronics and suitable for notebook PC backlighting, automotive infotainment displays, and digital picture frame designs requiring stable component supply, RoHS-compliant packaging, and production-ready thermal performance.

Supply support for MP3384EQ-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 across Asia and North America.

The MP3384 belongs to MPS's WLED backlight driver product line, engineered specifically for energy-efficient, fault-resilient LCD backlight systems in portable and automotive displays.

FAQ

What is the minimum recommended input voltage for reliable startup?

The MP3384EQ-LF-P requires VIN ≥4.5V to initiate startup; below 3.6V it remains disabled due to under-voltage lockout. At 4.1V (typical UVLO rising threshold), the internal 5V LDO begins powering control circuitry, and soft-start commences once VCC stabilizes above 4.5V.

How does the IC handle an open LED string during operation?

When an LED string opens, its LEDX pin voltage drops below 180mV. The MP3384EQ-LF-P detects this within 1.6ms, marks off the faulty string, and continues regulating remaining strings using the highest-voltage string as reference - maintaining partial backlight functionality without shutdown.

Can the MP3384EQ-LF-P operate with VIN below 5.5V?

Yes - when VIN <5.5V, the internal VCC LDO cannot regulate. In this case, VCC must be externally supplied with a stable 5V source, and VIN can go as low as 4.5V. The EN pin must still exceed 1.8V to enable operation.

What is the purpose of the exposed thermal pad on the QFN16 package?

The exposed pad (connected internally to PGND) serves as the primary thermal path. It must be soldered to a dedicated PGND copper area ≥30mm² with ≥4 thermal vias to inner ground planes. This reduces θJA from 60°C/W to ≤40°C/W, preventing thermal shutdown at full load.

Is PWM dimming compatible with analog dimming methods?

No - the MP3384EQ-LF-P supports only PWM dimming via the dedicated PWM pin. Analog dimming (e.g., varying ISET voltage) is not supported; attempting to modulate ISET causes unstable current regulation and violates the 1.21V reference design.

What happens if the OSC pin is left unconnected?

An unconnected (floating) OSC pin defaults to 1.25MHz switching frequency, as specified in the datasheet. However, for robust EMI control in production, it is recommended to tie OSC to VCC with a 10kΩ pull-up rather than relying on floating state.

How is overvoltage protection configured for a 40V nominal output?

To protect a 40V output, set the OVP threshold to ~52V (1.3×40V). Using VOVP = 1.23V × (R1+R2)/R2, select R1 = 324kΩ and R2 = 10kΩ - yielding VOVP = 1.23V × 33.4 = 41.1V. Adjust R1 upward to reach target; verify with actual output measurement.