Monolithic Power Systems Inc. MP3394SGF-P

Overview

MP3394SGF-P from Monolithic Power Systems is a step-up white LED driver IC with four independent current-regulated channels, designed for large LCD panel backlighting. It operates from 5V to 28V input, delivers up to 200mA per string, achieves 2.5% inter-string current matching, and supports programmable switching frequency (140–670 kHz) via external resistor. Used in flat-panel TVs and monitors where precise brightness uniformity across multiple LED strings is critical.

For engineers reviewing the MP3394SGF-P datasheet, MP3394SGF-P pinout, MP3394SGF-P application, or MP3394SGF-P equivalent, key selection considerations include its TSSOP16EP package thermal performance (θJA = 45°C/W), dual dimming modes (external PWM and DC-input burst PWM), open/short LED fault protection, and cascading capability for 8+ string configurations using multiple ICs.

Technical Context

The MP3394SGF-P implements peak-current-mode control with fixed-frequency operation, where switching frequency is set by an external resistor on the OSC pin and internal oscillator voltage is regulated to 1.22 V. It integrates four matched current sinks (LED1–LED4) with 300 mV regulation voltage and uses an internal error amplifier driving the COMP pin for loop compensation.

Dimming is implemented via two distinct paths: DBRT accepts either a direct PWM signal (100 Hz–20 kHz) or a 0.2–1.2 V analog voltage that modulates an internally generated DPWM waveform whose frequency is set by a capacitor on BOSC. Protection logic continuously monitors OVP, LEDX pin voltages (106–286 mV UVLO, 5.6–6.6 V OV), ISENSE, and die temperature (150°C shutdown).

Key Specifications

Pinout & Package

TSSOP16EP package with exposed thermal pad (must be connected to GND); 4.4 mm × 5.0 mm footprint; 0.65 mm pitch; RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-channel WLED driver applications.

Compared with ISL97684IRZ-T7A and LM3409QMY/NOPB, the MP3394SGF-P uniquely combines programmable frequency, 200 mA/string capability, 2.5% matching, and seamless cascading-making it optimal for scalable, high-uniformity LCD backlight systems where thermal management and fault resilience are critical.

Availability

MP3394SGF-P is available at Aetrix Electronics and suitable for desktop LCD flat panel displays, 2D/3D LCD TVs, and industrial HMI monitors requiring stable component supply, consistent parametric performance across production lots, and long-term lifecycle availability.

Supply support for MP3394SGF-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, and motor control.

The MP3394S product line targets large-format LCD backlighting applications, emphasizing high current accuracy, thermal robustness, and system-level fault coverage to replace discrete LED driver solutions in consumer and industrial displays.

FAQ

What is the maximum allowable LED string voltage when using MP3394SGF-P?

The MP3394SGF-P does not directly regulate string voltage; it regulates current while supporting output voltages up to 55 V on LED1–LED4 pins. The practical maximum string voltage depends on external boost stage design - typically limited by the external MOSFET's VDS rating and Schottky diode reverse voltage. For reliable operation, keep string voltage ≤80% of MOSFET VDS(MAX) to accommodate switching transients.

Can MP3394SGF-P operate with only three LED strings connected?

Yes. The MP3394SGF-P automatically detects active strings via LEDX pin voltages and regulates only those with valid forward voltage. Unused LEDX pins (e.g., LED4) must be left unconnected - not grounded or pulled high - to avoid false fault triggering. Open-string protection remains active for any disconnected channel.

How does the ISENSE pin function in single-IC versus cascaded configurations?

In single-IC operation, ISENSE monitors the external current-sense resistor (RSENSE) for peak-current-mode control and cycle-by-cycle limiting. In cascaded setups, only the master IC uses ISENSE; slave ICs require ISENSE tied to GND to disable their current-sense circuitry and prevent conflict with the master's regulation loop.

What is the minimum recommended DBRT input voltage for full dimming range in DC-input mode?

In DC-input PWM dimming mode, the DBRT pin requires 0.2 V to 1.2 V for 0% to 100% dimming duty cycle. Voltages below 0.2 V force 0% output; above 1.2 V clamp at 100%. A precision DAC or filtered PWM output is recommended to maintain linearity - resistor-divider networks may introduce drift due to temperature coefficient mismatch.

Does MP3394SGF-P support analog (DC) brightness control without PWM?

No. The MP3394SGF-P only supports PWM-based dimming: either externally applied PWM on DBRT or internally generated burst PWM driven by a DC voltage on DBRT. There is no true analog current adjustment - the IC always operates in switched-current mode, with average LED current determined by PWM duty cycle, not DBRT voltage level alone.

What thermal derating applies to the TSSOP16EP package at 85°C ambient?

With θJA = 45°C/W and TJ(MAX) = 150°C, the maximum allowable power dissipation at 85°C ambient is (150 − 85) / 45 = 1.44 W. At full 200 mA/string (4 strings), total LED power can exceed this - therefore, thermal design must rely on the exposed pad (θJC = 10°C/W) and multilayer PCB copper pour to maintain junction temperature within limit.