Monolithic Power Systems Inc. MP3373GY-P

Overview

MP3373GY-P from Monolithic Power Systems is an 8-channel step-up WLED controller with external transistor drive, designed for large LCD panel backlighting. It operates from 9V–40V input, delivers 1.2% current matching across strings, supports programmable 100kHz–1MHz switching frequency via ROSC, and features phase-shift PWM dimming to suppress inrush current and audible noise in TV/monitor backlight systems.

For engineers reviewing the MP3373GY-P datasheet, MP3373GY-P pinout, MP3373GY-P application, or MP3373GY-P equivalent, key selection criteria include its 8-channel external current sink architecture, 200mV CTLX regulation voltage, open/short LED protection with fault flag output, thermal shutdown at 150°C, and compatibility with SOIC-28 packaging for high-power backlight designs.

Technical Context

The MP3373GY-P implements peak-current-mode, fixed-frequency boost control with an internal 10V LDO (VCC) powering gate drivers and logic. Its 8 independent CTLx/FBx pairs regulate external NPN transistors per string, using 200mV reference feedback and achieving ±1.2% inter-string current matching under full load.

Protection architecture includes cycle-by-cycle ISENSE-based overcurrent latching (VLMT_SD = 430mV), OVP threshold detection (2.5V rising edge), CTLX UVLO (205mV), and thermal shutdown with 25°C hysteresis. Phase shift timing is dynamically adjusted based on active string count-45° for 8 strings, 60° for 6, and 90° for 4-to maintain low RMS input current without external synchronization.

Key Specifications

Pinout & Package

MP3373GY-P is housed in a SOIC-28 package (body size 17.9mm × 7.5mm, 1.27mm pitch), optimized for thermal dissipation in high-current backlight applications. The exposed pad variant is not used; thermal management relies on PCB copper area under pins 25 (PGND) and 27 (GATE).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar WLED controller applications.

Compared with MP3372GM-P and RT9397BF, MP3373GY-P uniquely combines 8-channel external drive, sub-1.5% matching, phase-shift PWM, and SOIC-28 thermal capability-making it the only option qualified for high-reliability, large-panel backlight systems requiring field-serviceable current sources and multi-IC scalability.

Availability

MP3373GY-P is available at Aetrix Electronics and suitable for large-format LCD TVs, professional monitors, and industrial control panels requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for MP3373GY-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 MP3373 product line targets high-efficiency, high-channel-count WLED backlighting for premium displays, emphasizing precision current regulation, robust fault handling, and flexible dimming architectures for industrial and broadcast-grade applications.

FAQ

What is the purpose of the PSEN pin on MP3373GY-P?

The PSEN pin enables or disables the automatic phase-shift PWM dimming function. When left floating, it activates staggered 45°/60°/90° delays between LED strings to reduce input ripple and eliminate audible noise. Pulling PSEN to GND disables this feature, synchronizing all strings to the same PWM edge for simplified timing analysis.

Can MP3373GY-P drive MOSFETs directly, or does it require external transistors?

MP3373GY-P does not integrate power switches and requires external NPN transistors (or N-channel MOSFETs with level-shifting) for LED current regulation. Its CTLx pins provide 320mV-sink outputs to bias external transistor bases, while FBx pins monitor emitter current via sense resistors-enabling high-current, thermally isolated string control.

How does MP3373GY-P handle open LED string faults?

It detects open strings via CTLx pin voltage monitoring. If a CTLx voltage drops below 205mV (UVLO threshold), the IC marks that string as inactive, disables its feedback loop, and continues regulating remaining strings. The FAULT pin pulls low to signal the event, and the output bus voltage is maintained by the highest-voltage active string.

What is the minimum recommended input capacitance for MP3373GY-P?

The datasheet specifies a minimum 4.7μF X5R/X7R ceramic capacitor in parallel with a 220μF electrolytic capacitor at VIN. This combination ensures low impedance at the switching frequency (100kHz–1MHz), suppresses input surge current, and maintains stable operation during transient load steps typical in backlight dimming sequences.

Is MP3373GY-P compatible with multi-IC configurations for more than 8 LED strings?

Yes-MP3373GY-P supports master-slave expansion. Two or three ICs can share a single boost power stage (inductor, diode, MOSFET) by connecting their ISENSE pins together and configuring one as master (ISENSE tied to sense resistor) and others as slaves (ISENSE tied to GND). This scales channel count to 16 or 24 strings without duplicating magnetics.

What thermal derating applies to MP3373GY-P in SOIC-28 package?

In SOIC-28, MP3373GY-P has θ_JA = 60°C/W. At 25°C ambient, maximum continuous power dissipation is 2.08W. Above 25°C, allowable power decreases linearly: e.g., at 70°C ambient, max power drops to 1.28W. Layout with ≥2 cm² of 2-oz copper connected to PGND (Pin 25) is required to sustain full-load operation.

Does MP3373GY-P support both analog and PWM dimming simultaneously?

No-it supports either analog dimming (0.4–1.5V DC on DIM pin) or PWM dimming (≥1.6V square wave on EN/PWMI or DIM), but not both concurrently. The IC interprets the signal type based on voltage amplitude and ignores conflicting inputs; mixing modes causes undefined behavior and potential regulation instability.