Monolithic Power Systems Inc. MP3388EY-LF-P

Overview

MP3388EY-LF-P from Monolithic Power Systems is an 8-channel white LED driver IC with integrated step-up converter, designed for large LCD panel backlighting. It delivers up to 50V output from 4.5–25V input, regulates 20mA per string with ±3% matching accuracy, and supports selectable 1.25MHz/625kHz switching frequency. Used in notebook PCs and small LCD TVs where precise multi-string current control and compact layout are critical.

For engineers reviewing the MP3388EY-LF-P datasheet, MP3388EY-LF-P pinout, MP3388EY-LF-P application, or MP3388EY-LF-P equivalent, key selection criteria include its 8-channel independent current regulation, 600mV LED current sense voltage, dual PWM/DC dimming modes, OVP/short/open-LED protection, and SOIC28 thermal performance (θJA = 60°C/W).

Technical Context

The MP3388EY-LF-P integrates a fixed-frequency peak-current-mode boost controller with eight matched open-drain current sinks. Its internal 5V LDO (VCC) powers gate drivers and logic, while the COMP pin enables loop compensation via external RC networks. The device uses a 1.23V OVP reference and 1.22V ISET reference to set overvoltage threshold and LED current respectively.

Dimming is implemented through four configurable modes: external PWM on PWMI, DC analog on PWMO, or direct PWM with internal triangle waveform generation. Fault handling includes programmable OVP, 1.6ms short-string detection, and thermal shutdown at 150°C - all managed without external microcontroller intervention.

Key Specifications

Pinout & Package

MP3388EY-LF-P is housed in a 28-pin SOIC package (17.9mm × 7.5mm × 2.3mm), with exposed pad not present. Pin 1 is marked by notch or dot; pins 15, 17, 25, and 27 are NC. PGND1 and PGND2 must be externally shorted; SW1 and SW2 must be shorted to form a single high-current switch node.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP3388EY-LF-P, MP3389EY-LF-Z offers improved current matching and temperature range but shares identical SOIC28 footprint and control interface; LM3409QMY/NOPB provides greater topology flexibility but increases component count and design complexity for 8-string systems.

Availability

MP3388EY-LF-P is available at Aetrix Electronics and suitable for notebook PC backlighting, small LCD TV backlighting, and handheld terminal display applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP3388EY-LF-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.

The MP3388 product line targets LCD backlighting applications, delivering integrated boost converters and precision current sources to replace discrete solutions in space-constrained consumer and industrial displays.

FAQ

What is the maximum number of LEDs supported per string by MP3388EY-LF-P?

The MP3388EY-LF-P supports up to 10 white LEDs per string when driven at typical forward voltage of 3.3V, based on its 50V maximum output capability. This assumes no additional voltage drop across external components like Schottky diodes or PCB traces. The actual count depends on total string V_F sum and desired headroom for regulation margin.

Can MP3388EY-LF-P operate with input voltage below 4.5V?

No - the absolute minimum input voltage is 4.5V per datasheet specifications. Below this, the internal UVLO circuit prevents startup. If the system requires operation below 4.5V, an external 5V supply must be applied directly to the VCC pin, bypassing the internal LDO, as specified in the "Internal 5V Regulator" section.

How is current matching accuracy achieved across 8 LED strings?

Current matching accuracy of ±3% is achieved using eight matched internal current sources referenced to a common 1.22V bandgap voltage and trimmed during wafer test. Each LEDX pin functions as an open-drain current sink with identical transconductance characteristics, ensuring balanced current distribution even under varying thermal gradients across the die.

What happens during an open LED string fault?

When an LED string opens, its corresponding LEDX pin voltage drops below 175mV, triggering open-string detection. The MP3388EY-LF-P marks off that string, disables its current sink, and continues regulating remaining strings. If all strings open, the boost converter shuts down after OVP threshold is reached, and VFAULT pulls low to disconnect input power via external PMOS.

Is MP3388EY-LF-P compatible with PWM dimming frequencies above 50kHz?

No - the datasheet specifies a maximum external PWM input frequency of 50kHz for reliable operation in standard PWM dimming mode. Higher frequencies may cause incomplete filtering at the PWMO pin or misinterpretation by the internal DPWM oscillator, leading to inconsistent dimming response or audible noise in the output stage.

Does MP3388EY-LF-P require external compensation components?

Yes - the COMP pin requires an external RC network (typically 1–10nF capacitor in series with 1–10kΩ resistor) connected to GND to stabilize the boost converter feedback loop. The exact values depend on selected inductor, output capacitance, and load conditions, and are detailed in the "Compensation Design" section of the datasheet.

What is the purpose of the VFAULT pin in system-level design?

The VFAULT pin drives an external PMOS transistor to physically disconnect the input supply from the rest of the system during fault conditions (OVP, thermal shutdown, or enable deactivation). This provides hardware-level isolation, preventing backfeed, protecting upstream power sources, and meeting safety requirements in certified display products.