Monolithic Power Systems Inc. MP3398HGS-P

Overview

MP3398HGS-P from Monolithic Power Systems is a 4-string step-up WLED controller with peak-current-mode control, designed to drive white LED arrays in large-panel LCD backlighting. It supports 4.5V–33V input, delivers up to 400mA per string, features 80V absolute maximum rating per LED string, 1.5% inter-string current matching, and configurable 400–600kHz switching frequency via ROSC. Used in desktop monitors and all-in-one PCs requiring precise, high-voltage LED current regulation.

For engineers reviewing the MP3398HGS-P datasheet, MP3398HGS-P pinout, MP3398HGS-P application, or MP3398HGS-P equivalent, this page provides verified technical context on cascading capability, OVP threshold configuration, PWM/ADIM dimming implementation, and SOIC-16 thermal derating at 125°C junction temperature.

Technical Context

The MP3398HGS-P implements fixed-frequency peak-current-mode control with external MOSFET drive (GATE pin), using ISENSE for cycle-by-cycle current limiting at 540mV and COMP for loop compensation. Its internal 5.9V LDO (VCC) powers gate driver and logic, with UVLO hysteresis of 350mV and hiccup-mode OTP at 150°C.

Four independent open-drain LEDx pins provide per-string current sinking with 360mV regulation voltage at 100mA, enabling precise current balancing across strings. Dimming is supported via direct PWM (PWM pin), analog PWM filtering (ADIM + capacitor), or DC voltage (0–1.5V on ADIM), with internal 100kΩ pull-up on ADIM and 1.5V/0.4V logic thresholds on PWM.

Key Specifications

Pinout & Package

MP3398HGS-P is housed in a 16-pin SOIC package with exposed pad (SOIC-16), optimized for thermal dissipation in high-current LED driver applications. Pin 15 is GND; pin 8 is VCC (5.9V LDO output); pin 7 is GATE (N-MOSFET driver); pins 1, 13–16 are LEDx cathode sinks; pin 2 is ISET (current-setting reference); pin 6 is ISENSE (peak-current sense input).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP3398HGS-P, MPQ3367-AEC1 trades discrete-FET flexibility and cascading for AEC-Q100 compliance and integration, while LM3409QMYX/NOPB offers lower cost per string but requires external circuitry to match MP3398HGS-P's 4-channel precision and dimming versatility.

Availability

MP3398HGS-P is available at Aetrix Electronics and suitable for desktop LCD flat-panel displays, all-in-one PCs, and 2D/3D LCD TVs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP3398HGS-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 power management ICs, with core expertise in DC/DC conversion, LED drivers, and motor control solutions.

The MP3398H product line targets large-format LCD backlighting, delivering high-voltage, multi-string WLED control with minimal external components and robust fault protection for display manufacturers.

FAQ

What is the minimum recommended ROSC value for stable 500kHz operation?

The MP3398HGS-P datasheet specifies ROSC = 100kΩ for 500kHz nominal switching frequency. Using a 1% tolerance metal-film resistor ensures frequency deviation remains within ±3%, critical for EMI compliance and inductor sizing. Values below 50kΩ risk instability due to increased oscillator current noise and reduced phase margin in the control loop.

How does the MP3398HGS-P handle an open LED string during operation?

When an LED string opens, its corresponding LEDx pin voltage drops below 200mV, triggering open-string detection. The IC marks that string as inactive, continues boosting VOUT until OVP threshold is reached, then regulates output based on remaining active strings' voltage demands. All strings remain functional after reset unless fault persists.

Can ADIM and PWM pins be used simultaneously for hybrid dimming?

No-ADIM and PWM serve mutually exclusive dimming modes. Pulling ADIM high to VCC enables direct PWM dimming on the PWM pin. For analog dimming, ADIM must be biased with a capacitor to GND and PWM driven with ≥20kHz signal; using both pins concurrently causes undefined behavior and potential current regulation errors.

What is the maximum allowable continuous power dissipation at 85°C ambient?

Using θJA = 80°C/W and TJ(MAX) = 150°C, PD(MAX) = (150 − 85) / 80 = 0.8125W. This assumes SOIC-16 mounted on a 4-layer PCB per JESD51-7. Exceeding this derates reliability and may trigger hiccup-mode OTP before reaching 150°C junction temperature.

Is cascading two MP3398HGS-P ICs compatible with independent dimming per string?

No-cascading configures all strings under master IC control. Slave ICs share COMP and VCC but disable their GATE drivers; dimming signals (PWM/ADIM) must be applied identically to both ICs. Independent per-string dimming requires separate controllers or a higher-channel IC like MPQ3367.

What failure modes trigger non-latching versus latching protection?

OCP, OTP (hiccup), and UVP are non-latching and auto-recover after fault removal. OVP, LED short, and inductor/diode short are latching-requiring EN toggle or VIN cycle to reset. This prevents repeated stress during persistent faults while allowing graceful recovery from transient overloads.

Does the 1.5% current matching specification hold across temperature and input voltage variation?

Yes-the 1.5% matching is characterized from −40°C to +125°C and across 4.5V–33V VIN. It reflects worst-case deviation between max/min string currents at fixed ISET, validated under full operating conditions, not just room-temperature typicals.