Monolithic Power Systems Inc. MPQ3387LGRT-AEC1-Z

Overview

MPQ3387LGRT-AEC1-Z 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 requiring high reliability under -40°C to +125°C operation.

For engineers reviewing the MPQ3387LGRT-AEC1-Z datasheet, MPQ3387LGRT-AEC1-Z pinout, MPQ3387LGRT-AEC1-Z application, or MPQ3387LGRT-AEC1-Z equivalent, this device delivers precise 6-string LED current control, programmable switching frequency (532–1250 kHz), 24–27.5 kHz audible-noise-free dimming output, and integrated OVP/OTP/LED open-short protection for safety-critical automotive displays.

Technical Context

The MPQ3387LGRT-AEC1-Z implements peak-current-mode PWM control with a programmable oscillator (via FREQ pin resistor) and internal 5 V LDO (VCC) for gate drive and logic. It regulates six LED strings independently using matched 600 mV current-sense reference and achieves ±3% current matching across strings at up to 45 mA per string.

Dimming is implemented via dual-mode control: MIX pin selects between pure PWM dimming (PWMI direct duty-cycle control) or combined analog/PWM mode with automatic 25% duty-cycle transition and frequency upshift (100 Hz–20 kHz input → 24–27.5 kHz output) to eliminate audible noise while preserving dimming linearity below 25%.

Key Specifications

Pinout & Package

The MPQ3387LGRT-AEC1-Z is housed in a thermally enhanced TQFN-24 package (4 mm × 4 mm, 0.5 mm pitch) with exposed pad tied to PGND for low thermal resistance (θ_JA = 42°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ3387GRT-AEC1-Z, the MPQ3387LGRT-AEC1-Z adds latched OCP for persistent fault indication and improved system diagnostics; versus LM3409QMY, it integrates six current sinks and eliminates external FETs and sense resistors-reducing BOM count and board area by >40% in multi-string backlight designs.

Availability

MPQ3387LGRT-AEC1-Z is available at Aetrix Electronics and suitable for automotive instrument clusters, infotainment displays, and HUD light engines requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for MPQ3387LGRT-AEC1-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 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 targets automotive-grade LCD backlighting, delivering integrated step-up conversion and precision multi-string LED current regulation in compact packages for space-constrained display modules.

FAQ

What is the purpose of the MIX pin on MPQ3387LGRT-AEC1-Z?

The MIX pin selects dimming mode: pulled high (default) enables combined analog/PWM dimming with 25% duty-cycle transfer point, while pulled low activates pure PWM dimming. This allows system designers to optimize for either low-noise analog control at mid-to-high brightness or simplified timing-critical PWM at full brightness-without changing hardware.

How does MPQ3387LGRT-AEC1-Z achieve 3% current matching between LED strings?

It uses six matched internal current sources with a shared 1.241 V reference and low 600 mV compliance voltage, calibrated during wafer test to ensure ≤3% deviation in current regulation across strings at 20 mA. No external trimming or feedback is required-matching is inherent to the monolithic die architecture.

Can MPQ3387LGRT-AEC1-Z operate with input voltage below 5.5 V?

Yes-when VIN < 5.5 V, the internal VCC regulator cannot sustain 5 V output, so VIN and VCC must be externally tied together. The IC remains fully functional, but the gate drive voltage follows VIN, reducing maximum achievable switching frequency and efficiency at very low input voltages.

What protection features are implemented in MPQ3387LGRT-AEC1-Z?

It integrates recoverable over-current protection (cycle-by-cycle), over-voltage protection (programmable via OVP pin), over-temperature shutdown (150°C trip, 20°C hysteresis), LED open-string detection (via LEDX pin voltage < 260 mV), and LED short-string detection (via LEDX pin voltage > 5.5 V). All protections auto-recover upon fault removal except latched OCP.

Is the TQFN-24 package of MPQ3387LGRT-AEC1-Z lead-free and RoHS compliant?

Yes-the device is fully lead-free and complies with the RoHS directive. The exposed thermal pad is electrically connected to PGND and must be soldered to a solid copper pour for optimal thermal performance and EMI reduction, as specified in MPS application note AN-107.

How is the switching frequency programmed on MPQ3387LGRT-AEC1-Z?

By connecting an external resistor between the FREQ pin and PGND. The relationship is F_SW(kHz) ≈ 62100 / R_OS(kΩ); for example, a 100 kΩ resistor sets 625 kHz. This allows optimization of inductor size, efficiency, and EMI profile without changing the IC.

Does MPQ3387LGRT-AEC1-Z support cascading with other MPQ3387L devices?

Yes-it supports master-slave cascading using the EN and fault flag signals (optional NC pin 21) to synchronize startup and coordinate fault reporting across multiple drivers in large-panel or multi-zone backlight systems, enabling unified brightness control and fail-safe behavior.