Monolithic Power Systems Inc. MP3394SGY-P

Overview

MP3394SGY-P from Monolithic Power Systems is a step-up white LED driver IC with four independent current-regulated channels, designed for large-size 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. It drives an external N-MOSFET to boost output voltage and regulates LED current using internal current sources.

For engineers reviewing the MP3394SGY-P datasheet, MP3394SGY-P pinout, MP3394SGY-P application, or MP3394SGY-P equivalent, key selection criteria include its SOIC20 package, 4-string WLED control architecture, open/short LED protection, dual-mode PWM dimming (external PWM or DC-input), and cascading capability for expanded channel count in flat-panel display designs.

Technical Context

The MP3394SGY-P implements peak-current-mode control with fixed-frequency operation, where switching frequency is set by an external resistor on the OSC pin and ranges from 140 kHz to 670 kHz. Its internal 5.8V LDO (VCC) powers gate drive and logic circuitry, and under-voltage lockout activates at 3.9V with 200mV hysteresis.

Dimming is implemented via two configurable modes: external PWM applied to DBRT with BOSC grounded via resistor, or DC analog input (0.2–1.2V) on DBRT with BOSC capacitor-programmed dimming frequency (1–2 kHz typical). Current regulation uses four matched internal current sinks, each referenced to a 1.22V ISET pin voltage, enabling precise per-string control without external op-amps.

Key Specifications

Pinout & Package

MP3394SGY-P is housed in a SOIC20 package with exposed pad (not thermally connected per datasheet; no thermal pad designation). Pin 1 is located at top-left corner adjacent to notch; pin numbering proceeds counter-clockwise. The package supports standard reflow profiles and offers improved thermal resistance (θJA = 72°C/W) versus SOIC16.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ3394-AEC1, MP3394SGY-P omits automotive qualification but retains identical electrical behavior and SOIC20 footprint-ideal for cost-sensitive industrial and consumer displays. Versus LM3409QMY/NOPB, it eliminates external matching circuitry and reduces design validation effort while delivering superior inter-string accuracy and integrated protection.

Availability

MP3394SGY-P is available at Aetrix Electronics and suitable for desktop LCD flat panel displays, 2D/3D LCD TVs, and industrial control panel displays requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP3394SGY-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 distribution through authorized partners.

The MP3394 product line targets large-format LCD backlighting applications, emphasizing high-current accuracy, multi-string integration, and robust fault handling to replace discrete LED driver solutions in display manufacturing.

FAQ

What is the maximum allowable LED string voltage that MP3394SGY-P can regulate?

The MP3394SGY-P does not directly specify a maximum output voltage; instead, it regulates based on feedback from the OVP pin. With proper resistor-divider scaling, it supports output voltages up to 55V on LEDX pins per absolute maximum ratings. Practical limit depends on external MOSFET VDS rating and Schottky diode breakdown voltage-typically configured for ≤45V in 10–12 LED series strings.

Can MP3394SGY-P operate with only three LED strings connected?

Yes. The device automatically detects active LEDX pins and regulates output voltage to the highest required string voltage. Unused LEDX pins (e.g., LED4) must be left unconnected-not tied high or low-to avoid false fault detection. Open-string protection remains active for any disconnected string.

How is thermal performance affected by the SOIC20 package compared to TSSOP16EP?

SOIC20 has θJA = 72°C/W versus 45°C/W for TSSOP16EP. At 1.74W max power dissipation, SOIC20 junction-to-ambient rise is ~125°C at 25°C ambient-within 150°C limit but requires careful board copper area and airflow. TSSOP16EP is preferred for high-power or compact layouts; SOIC20 suits cost-sensitive, lower-power, or legacy-compatible designs.

Does MP3394SGY-P support analog dimming without PWM generation?

No-true analog (linear) dimming is not supported. It offers DC-input PWM dimming: a 0.2–1.2V analog voltage on DBRT sets internal PWM duty cycle (0–100%), but output remains PWM-switched at frequency set by BOSC capacitor. No linear current control or analog current sink modulation is implemented.

What happens during startup if the OVP pin reads below 75mV?

The MP3394SGY-P enters protection lockout and halts switching. This condition indicates either missing Schottky diode, shorted boost output, or incorrect OVP divider. The IC remains disabled until EN is cycled low-high and OVP voltage exceeds 75mV, ensuring safe startup before enabling gate drive.

Is cascading two MP3394SGY-P units possible using only SOIC20 packages?

Yes. Tie VCC and COMP pins between master and slave units; connect EN and DBRT in parallel; ground ISENSE on slave; leave slave GATE unconnected. SOIC20's larger pad spacing simplifies routing versus TSSOP16EP, and thermal derating must account for combined power dissipation across both ICs on shared PCB area.