Monolithic Power Systems Inc. MPQ3387LGRT-P

Overview

MPQ3387LGRT-P from Monolithic Power Systems is an AEC-Q100 Grade 1 qualified step-up white LED driver with six independent current-regulated channels, 3% inter-string current matching accuracy, 45 V max output voltage, and combined analog/PWM dimming with 25% transfer point-designed for automotive LCD backlighting in instrument clusters and center displays.

For engineers reviewing the MPQ3387LGRT-P datasheet, MPQ3387LGRT-P pinout, MPQ3387LGRT-P application, or MPQ3387LGRT-P equivalent, key selection criteria include its 24–27.5 kHz audible-noise-free PWM dimming frequency, programmable switching frequency (532–1.25 MHz), 600 mV LED current-sense voltage, TQFN-24 (4×4 mm) package with exposed thermal pad, and integrated recoverable OVP/OCP/OTP protections.

Technical Context

The MPQ3387LGRT-P employs peak-current-mode PWM control with a resistor-programmable oscillator (FREQ pin), delivering up to 45 V from a 3–25 V input. Its internal 5 V LDO (VCC) powers gate drivers and logic, while dual LX outputs support high-efficiency boost topology with external inductor and Schottky diode.

Each of the six LED string terminals (LED1–LED6) hosts an open-drain current sink with 600 mV regulation voltage and ±3% matching; dimming mode is selected via MIX pin (high = combined analog/PWM, low = pure PWM), and PWMI accepts 100 Hz–20 kHz input signals automatically upshifted to 24–27.5 kHz to eliminate audible noise.

Key Specifications

Pinout & Package

TQFN-24 (4 mm × 4 mm) package with exposed thermal pad connected to PGND; 0.5 mm pitch; RoHS-compliant, AEC-Q100 Grade 1 qualified.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ3387AGRT-P, the MPQ3387LGRT-P adds AEC-Q100 Grade 1 validation and extended temperature screening-critical for automotive deployment-while LM3409QMYX/NOPB demands additional external circuitry to match basic functionality, increasing BOM count and layout complexity.

Availability

MPQ3387LGRT-P is available at Aetrix Electronics and suitable for automotive instrument clusters, center-stack infotainment displays, and industrial HMI panels requiring stable component supply, long-term lifecycle assurance, and AEC-Q100 compliance.

Supply support for MPQ3387LGRT-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, and global manufacturing partnerships.

The MPQ3387L product line delivers highly integrated, AEC-Q100 qualified LED drivers for automotive and industrial LCD backlighting-emphasizing precision current matching, noise-free dimming, and robust fault protection in compact packages.

FAQ

What is the minimum input voltage required for reliable startup?

The MPQ3387LGRT-P features an under-voltage lockout (UVLO) with a rising-edge threshold of 2.4–2.55 V and 200 mV hysteresis. Reliable startup occurs when VIN exceeds 2.55 V and remains above 2.35 V during operation. Below this, the IC disables switching and holds EN inactive until re-triggered.

How does the MPQ3387LGRT-P handle an open LED string fault?

When one or more LED strings open, the corresponding LEDX pin voltage drops below 260 mV. The IC detects this via concurrent OVP pin monitoring (<70 mV) and disables the affected string's current regulator while maintaining regulation on remaining strings. Full recovery occurs automatically once the open string is reconnected.

Can the switching frequency be synchronized to an external clock?

No-the MPQ3387LGRT-P uses an internal resistor-programmed oscillator on the FREQ pin and does not support external clock synchronization. Frequency is set solely by the resistor value (532 kHz–1.25 MHz), with no provision for master-slave sync or phase alignment across multiple devices.

What is the maximum allowable continuous LED current per string?

The absolute maximum rated current per string is 45 mA, verified across temperature and process corners. At 45 mA, the internal current sink operates with ≤600 mV regulation voltage and maintains ≤3% matching. Sustained operation at this level requires adequate PCB copper area and thermal vias under the exposed pad to limit junction temperature to ≤125 °C.

Is the FAULT flag pin (Pin 21) available on the MPQ3387LGRT-P package?

Yes-Pin 21 is designated NC in standard configuration but functions as an open-drain fault indicator when enabled via internal configuration (not user-selectable). During normal operation it floats; during OVP, OCP, OTP, or open-string faults, it pulls low. External pull-up is required for active-low signaling.

How is the 25% dimming transfer point implemented in hardware?

The 25% transfer point is fixed in silicon logic: when the PWMI duty cycle ≥25%, the internal DAC scales the ISET reference linearly (I_OUT = I_SET × DDIM); when <25%, the DAC clamps I_OUT to 25% × I_SET and the PWM generator multiplies DDIM by 4 to preserve average current-both paths are hardwired, not software-configurable.

Does the MPQ3387LGRT-P support I²C or SPI configuration?

No-the MPQ3387LGRT-P is a fully analog-configured device with no digital interface. All parameters-including dimming mode, OVP threshold, switching frequency, and current level-are set exclusively by external resistors and logic pins (MIX, EN, PWMI); no firmware, registers, or serial communication are involved.