Monolithic Power Systems Inc. MP3393EY-LF-Z

Overview

MP3393EY-LF-Z from Monolithic Power Systems is an 8-string step-up white LED driver controller with external N-MOSFET and PNP transistor support, designed for large LCD panel backlights. It delivers 50–300mA per string with 1.2% current matching accuracy, 202mV FB regulation voltage, and programmable 100–500kHz switching frequency via OSC pin resistor. Used in LCD TVs requiring high-channel-count, thermally stable backlight power.

For engineers reviewing the MP3393EY-LF-Z datasheet, MP3393EY-LF-Z pinout, MP3393EY-LF-Z application, or MP3393EY-LF-Z equivalent, key selection criteria include its 8-channel constant-current architecture, external transistor control (CTLx pins), fault flag (FF) reporting, daisy-chain capability for channel expansion, and SOIC28 package thermal performance (θJA = 60°C/W).

Technical Context

The MP3393EY-LF-Z implements peak-current-mode step-up control with internal 10V LDO (VCC) powering gate drivers and logic. Its error amplifier compares 320mV reference against FBx feedback to regulate CTLx sink current (5.5–13.5mA), driving external PNP transistors for per-string current control.

It integrates open/short LED protection via CTLx voltage monitoring (UVLO <210mV, OV >6.4V), over-voltage protection triggered at 1.23V on OVP pin, thermal shutdown at 150°C, and fault reporting through open-drain FF pin pulled low during faults.

Key Specifications

Pinout & Package

MP3393EY-LF-Z is housed in a 28-pin SOIC package with exposed pad (not thermally connected in SOIC variant), rated for 2.1W continuous power dissipation at +25°C ambient (θJA = 60°C/W). Pin 1 is VIN; pin 28 is VFAULT; pin 25 is GND; pin 27 is GATE; and pins 7–22 serve dual FBx/CTLx roles for 8 channels.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-channel LED driver applications.

Compared with MP3393EY-LF-Z, MP3394EY-LF-Z offers higher current headroom and better thermal resistance but identical feature set, while LM3409QMY/NOPB demands significant external components to match basic 8-string functionality and lacks integrated fault signaling.

Availability

MP3393EY-LF-Z is available at Aetrix Electronics and suitable for LCD TV backlighting, professional monitor design, industrial HMI displays, and digital signage requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP3393EY-LF-Z 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.

The MP3393 product line targets large-panel LCD backlighting, delivering integrated multi-string control, robust fault management, and layout-efficient external transistor architecture for cost-sensitive, high-reliability display systems.

FAQ

What is the maximum LED string current supported by MP3393EY-LF-Z?

The MP3393EY-LF-Z regulates up to 300mA per string under recommended operating conditions (TA ≤ +85°C, proper PCB thermal design). The datasheet specifies "Maximum Channel Current Over 350mA" as an absolute rating, but sustained operation above 300mA requires derating based on θJA = 60°C/W and ambient temperature to avoid thermal shutdown.

Can MP3393EY-LF-Z drive MOSFETs directly, or does it require external transistors for LED current control?

MP3393EY-LF-Z drives an external N-channel MOSFET via its GATE pin for the boost converter, but uses CTLx pins to sink current into the bases of external PNP transistors - not MOSFETs - for per-string LED current regulation. It does not integrate high-side or low-side LED current switches; discrete PNP BJTs are mandatory for string control.

How does the daisy-chain configuration work between two MP3393EY-LF-Z ICs?

In daisy-chain mode, the master MP3393EY-LF-Z drives the shared boost inductor and MOSFET; its COMP and VCC pins connect to the slave's COMP and VCC pins. The slave's ISENSE pin must be tied to GND, and EN/DIM signals are applied to both. Only the master's GATE and FF pins are active; the slave provides additional CTLx/FBx channels without duplicating power-stage components.

What is the purpose of the VFAULT pin, and how is it used in system design?

VFAULT is a gate-drive output that controls an external P-channel MOSFET between VIN and the boost converter input. During normal operation, VFAULT rises to VIN, turning on the PMOS to enable power flow. When EN = low or a fault occurs, VFAULT drops to GND, turning off the PMOS to disconnect input power - providing safe, controlled input isolation for system-level safety compliance.

Does MP3393EY-LF-Z support PWM dimming frequencies above 2kHz?

No - the datasheet specifies external PWM dimming support from 50Hz to 2kHz. Operation above 2kHz may cause inconsistent dimming due to insufficient settling time in the internal current control loop and reduced effective duty-cycle resolution; for higher-frequency dimming, analog dimming (0.4–1.5V DC on DIM pin) is recommended.

Is the SOIC28 package of MP3393EY-LF-Z thermally enhanced like the TSSOP28EP variant?

No - the SOIC28 package (used in MP3393EY-LF-Z) has no exposed thermal pad and exhibits higher thermal resistance: θJA = 60°C/W versus 32°C/W for TSSOP28EP. While functional, SOIC28 requires more conservative power derating and larger copper pours for equivalent thermal performance in high-current applications.