Monolithic Power Systems Inc. MP4012DS-LF-P

Overview

MP4012DS-LF-P from Monolithic Power Systems is a high-voltage, constant-current WLED controller supporting 8V–55V input and driving external MOSFETs in Boost, Buck-Boost, SEPIC, and Buck topologies. It delivers ±2% LED current accuracy via ISET/FB feedback, features programmable 100–650 kHz switching frequency (RT-pin set), and integrates high-frequency PWM dimming with analog dimming via ISET voltage adjustment. Used in high-brightness LCD backlighting with 200V output and 120mA LED string current.

For engineers reviewing the MP4012DS-LF-P datasheet, MP4012DS-LF-P pinout, MP4012DS-LF-P application, or MP4012DS-LF-P equivalent, key selection criteria include its wide-input-range current-mode architecture, dual-mode operation (constant frequency or constant off-time), integrated OVP/short/open-load hiccup protection, and synchronization capability across multiple ICs for noise-sensitive multi-string LED systems.

Technical Context

The MP4012DS-LF-P implements peak current-mode control with programmable slope compensation (SL pin) to ensure loop stability at duty cycles >50%, using internal 100 ns leading-edge blanking on the CS pin to reject switch-node spikes. Its dual regulation modes-fixed-frequency (RT-to-GND) or constant off-time (RT-to-GATE)-allow topology-specific optimization without external compensation redesign.

It integrates a 7.75V internal linear regulator (VDD) powering gate drive and logic, a 1.243V ±1% bandgap reference (REF), and independent comparators for overvoltage (OVP pin threshold = 4.95V), short-circuit (200% I_LED limit), and thermal shutdown (150°C). Fault recovery uses a 5μA COMP-pin hiccup timer with programmable RC network.

Key Specifications

Pinout & Package

MP4012DS-LF-P is housed in a 16-pin SOIC package (JEDEC MS-012 AC compliant), with 1.27 mm pitch, 10.0 mm × 3.9 mm body, and exposed pad not present. Thermal resistance θ_JA = 80°C/W on 4-layer PCB per JESD51-7.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP4012DS-LF-P, MPQ4012-AEC1 adds automotive qualification without changing functionality, while LT3761EFE#PBF trades sync capability for higher voltage rating and integrated diode - making MP4012DS-LF-P optimal for cost-sensitive, multi-string, EMI-critical LCD backlight systems.

Availability

MP4012DS-LF-P is available at Aetrix Electronics and suitable for LCD backlighting, industrial LED lighting, and automotive cabin lighting requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP4012DS-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, and global manufacturing partnerships.

The MP4012 belongs to MPS's high-voltage LED controller product line, engineered specifically for energy-efficient, high-brightness WLED applications demanding wide input range, precise current regulation, and robust fault protection in space-constrained designs.

FAQ

What topologies does MP4012DS-LF-P support, and how is mode selection implemented?

The MP4012DS-LF-P supports Boost, Buck, Buck-Boost, and SEPIC topologies. Topology selection is determined by external circuit configuration-not by internal programming. Mode selection refers only to regulation timing: connect RT to GND for constant-frequency mode (510–650 kHz), or RT to GATE for constant-off-time mode. Both modes maintain current-mode control and full protection functionality.

How is LED current accuracy maintained across temperature and input voltage variations?

MP4012DS-LF-P achieves ±2% LED current accuracy through a trimmed 1.243V ±1% internal reference (REF), matched current-sense amplifier gain, and feedback path designed for minimal drift. The ISET pin voltage-set by a resistor divider from REF-is used to scale the FB regulation target, decoupling current setting from VDD or VIN fluctuations. Electrical characterization confirms this tolerance over −40°C to +125°C junction temperature and 8V–55V input.

Can MP4012DS-LF-P synchronize with non-MPS controllers, and what are the electrical requirements?

Yes-MP4012DS-LF-P's SYNC pin operates as an open-drain input/output compatible with any 0–5.5V logic-level clock source. To synchronize with non-MPS controllers, connect the master clock's open-drain output (with pull-up to ≤5.5V) directly to MP4012DS-LF-P's SYNC pin. The IC locks to the highest-frequency oscillator in the group. No level-shifting or additional biasing is required beyond standard pull-up.

What is the role of the SL pin, and when can it be left unconnected?

The SL (Slope Compensation) pin injects a ramp signal into the current-sense comparator to prevent subharmonic oscillation in peak current-mode control when duty cycle exceeds 50%. It must be connected to GND via a 25–50 kΩ resistor in constant-frequency mode. In constant-off-time mode, slope compensation is inherently unnecessary due to control-loop dynamics, so SL may be left floating with no performance impact.

How does the hiccup-mode protection recover after an overvoltage fault?

Upon OVP detection (OVP pin ≥4.95V), MP4012DS-LF-P pulls FAULT low, disables GATE, and disconnects COMP from the error amplifier. Recovery begins when output voltage falls below the falling threshold (4.45V). An internal 5μA current source then charges COMP from 1V to 5V, followed by discharge back to 1V - a full hiccup cycle lasting ~100 ms with typical 10 nF COMP capacitor. Only after COMP reaches 1V does regulation resume.

Is there a recommended minimum value for the current-sense resistor (R_FB) on the FB pin?

Yes - R_FB should be sized so the voltage drop at maximum LED current remains within the FB pin's valid common-mode range (0.8V to 5.5V) and avoids excessive power dissipation. For 120mA LED current and 1.243V reference, R_FB = 1.243V / 0.12A ≈ 10.36Ω. A standard 10Ω, 1% metal-film resistor dissipates 149 mW - requiring ≥1/4W rating. Values below 5Ω risk violating FB input range under tolerance and noise margin.

Does MP4012DS-LF-P support true analog dimming, and how is it implemented?

Yes - true analog dimming is implemented by varying the DC voltage applied to the ISET pin, which directly scales the FB regulation target. This is achieved either via a resistor divider from the 1.243V REF pin (most common) or an external DAC. Unlike PWM dimming, analog dimming adjusts current continuously, eliminating flicker and enabling smooth intensity transitions - verified in typical application circuits with <1% current ripple at 0–100% dimming range.