Monolithic Power Systems Inc. MP3351DQ-LF-P

Overview

MP3351DQ-LF-P from Monolithic Power Systems is a 60V, 2A integrated photo-flash charger IC with built-in IGBT driver for xenon flash circuits in portable imaging systems. It features a 200mΩ internal power switch, programmable peak current (300mA–2A via external resistor), ±3% charge voltage accuracy via external feedback, and operates from 3V–6V single/dual-cell Li+ battery input. Used to rapidly charge high-voltage flash capacitors up to 300V in digital still cameras.

For engineers reviewing the MP3351DQ-LF-P datasheet, MP3351DQ-LF-P pinout, MP3351DQ-LF-P application, or MP3351DQ-LF-P equivalent, key selection criteria include peak charge current programming, IGBT gate drive timing (45ns propagation delay), critical conduction mode (DCM) boundary control, thermal shutdown threshold (150°C), and QFN16-3mm×3mm package compatibility with high-density PCB layouts.

Technical Context

The MP3351DQ-LF-P implements a fixed-frequency flyback controller operating up to 400kHz in critical conduction mode, using peak current sensing at the ISET pin and FB-based output voltage regulation. Its DCM comparator monitors FB voltage against a 25mV offset to detect zero-current crossing, enabling efficient light-load operation.

Integrated IGBT driver supplies both pull-up (4Ω) and pull-down (4Ω) paths to the IGBTIN/IGBTOUT pins, supporting fast switching (60ns rise, 70ns fall) into 6500pF gate capacitance. Internal 60V-rated SW node and 200mΩ MOSFET minimize primary-side losses while enabling lower transformer turns ratios.

Key Specifications

Pinout & Package

MP3351DQ-LF-P is housed in a thermally enhanced 16-pin QFN package (3mm × 3mm, 0.5mm pitch) with an exposed power ground pad (pins 7, 8) for optimal heat dissipation. The package complies with JEDEC MO-220 VEED-4 and supports reflow soldering at 260°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar photo-flash charger applications.

Compared with MAX8620Y and TPS613222A, MP3351DQ-LF-P uniquely combines 60V flyback switching, 2A programmable current, and integrated IGBT drive in a single 3×3mm package-enabling complete xenon flash subsystems with minimal external components and guaranteed timing coordination between charge completion and tube trigger.

Availability

MP3351DQ-LF-P is available at Aetrix Electronics and suitable for digital still cameras, mobile phone camera modules, optical film cameras, and PDA imaging systems requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP3351DQ-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 core expertise in DC/DC conversion, LED drivers, motor drivers, and battery management.

The MP3351 belongs to MPS's photo-flash power management product line, engineered specifically for compact, high-efficiency xenon flash charging in battery-powered imaging devices where integration, thermal performance, and precise timing are critical.

FAQ

What is the minimum input voltage required to initiate charging?

The MP3351DQ-LF-P features an input UVLO with a rising threshold of 2.8V (±0.1V) and 200mV hysteresis. Charging will not begin until VIN exceeds 2.8V; operation ceases if VIN drops below 2.7V. This ensures reliable startup from partially discharged Li+ cells while preventing erratic behavior near battery cutoff.

How is output voltage accuracy maintained across temperature and battery voltage variation?

Output voltage accuracy is maintained at ±3% via external resistive feedback to the FB pin, referenced to a trimmed 1.20V internal bandgap. The FB input bias current is tightly controlled (±0.2µA), minimizing divider error, and the 25mV DCM comparator offset compensates for propagation delays across –40°C to +85°C.

Can the IGBT driver operate independently of the charger circuit?

Yes. The IGBT driver is powered from VIN and controlled solely by the IGBTIN pin. It remains functional even when the charger is disabled (CHARGE = low), allowing separate control of xenon tube triggering-for example, to fire a pre-flash before main exposure without recharging the capacitor.

What is the purpose of the RDYB pin, and how should it be interfaced?

RDYB is an open-drain output that pulls low when the FB pin reaches 1.20V, indicating flash capacitor charge completion. It must be pulled up externally (typically 10kΩ to VIN). RDYB's 2mA sink capability allows direct connection to microcontroller GPIO or optocoupler inputs for precise flash timing synchronization.

How does the DCM comparator improve efficiency during flash charging?

The DCM comparator detects zero-current crossing by comparing FB voltage to a 25mV offset. When enabled, it shortens off-time as the capacitor nears full charge, maintaining critical conduction mode and reducing switching losses at light loads-extending battery life by up to 18% compared to fixed-frequency operation near termination.

Is the exposed thermal pad electrically isolated or connected internally?

The exposed pad (pins 7, 8) is internally connected to PGND and must be soldered to a dedicated PGND copper pour on the PCB. It is not electrically isolated and serves as the primary thermal and current return path for the internal power switch and IGBT driver-failure to connect it degrades thermal performance and may cause premature thermal shutdown.

What is the recommended R_SET value for 1.5A peak charge current?

Per the datasheet equation R_SET(kΩ) = 50 / I_PEAK(A), a 1.5A target requires R_SET = 33.3kΩ. A standard 33.2kΩ ±1% resistor yields I_PEAK = 1.504A (typical), well within the specified 1.32–1.68A range for that resistance tolerance and process variation.