Monolithic Power Systems Inc. MP4033GS-Z

Overview

MP4033GS-Z from Monolithic Power Systems is a TRIAC-dimmable, primary-side-control offline LED controller with integrated active PFC, designed for isolated flyback LED drivers up to 50W. It delivers accurate LED current regulation using real-current-control methodology, operates in boundary-conduction mode (BCM), and supports analog dimming via PWM input or phase-cut dimmers. Its integrated VCC charging circuit enables fast start-up, and the DIM pin enables warm sunset color-temperature/brightness control.

For engineers reviewing the MP4033GS-Z datasheet, MP4033GS-Z pinout, MP4033GS-Z application, or MP4033GS-Z equivalent, key selection considerations include TRIAC dimmer compatibility (leading/trailing edge detection), programmable NTC-based thermal fold-back, ZCD-based zero-current switching, cycle-by-cycle current limiting, and SOIC-8 package suitability for compact LED driver designs.

Technical Context

The MP4033GS-Z implements proprietary real-current-control using primary-side sensing-eliminating optocoupler and secondary-side feedback-by deriving LED current from VREF (0.414 V), turn ratio (N), and sense resistor (Rs) per I_LED ≈ (V_REF × N) / (2 × R_s). Its multiplier circuit shapes primary current into a sinusoid aligned with rectified line voltage to achieve >0.9 PF.

It detects dimmer type adaptively via MULT pin thresholds (e.g., VMULT_LD_LOW = 0.10 V, VMULT_TL_HIGH = 0.45 V) and employs dual blanking timers (tZCD_LEB = 2.3 µs, tOVP_LEB = 2.3 µs) to reject noise during ZCD sampling and OVP detection. The internal low-side MOSFET (BVDSS = 30 V, R_DS(ON) = 250 mΩ) drives external high-side switches in BCM operation.

Key Specifications

Pinout & Package

MP4033GS-Z is packaged in SOIC-8, with all 8 pins electrically functional and mapped to core control, sensing, and drive functions. No NC (no-connect) pins are present in this variant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TRIAC-dimmable primary-side LED controller applications.

Compared with MP4032GS-Z and BP5778E, MP4033GS-Z uniquely integrates NTC-based thermal fold-back, DIM-driven warm-dimming, and self-contained active PFC-making it the only option among the three that supports full-feature residential/commercial smart LED drivers in SOIC-8.

Availability

MP4033GS-Z is available at Aetrix Electronics and suitable for residential LED downlights, commercial office troffers, and industrial high-bay fixtures requiring stable component supply, long-lifecycle assurance, and RoHS-compliant manufacturing.

Supply support for MP4033GS-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 over 20 years of leadership in DC/DC converters, LED drivers, and motor drivers.

The MP4033 belongs to MPS's primary-side-controlled LED driver product line, engineered specifically for cost-sensitive, high-reliability AC/DC LED lighting systems demanding TRIAC compatibility, active PFC, and thermal intelligence without secondary feedback.

FAQ

What dimmer types does MP4033GS-Z support?

MP4033GS-Z supports both leading-edge (TRIAC) and trailing-edge (electronic low-voltage) dimmers through adaptive detection. It identifies dimmer type within 100 µs using MULT pin voltage thresholds and timing windows (tLEADING = 100 µs, tTRAILING = 450 µs), enabling deep dimming down to 1% with >95% recognition rate across major residential dimmer brands.

How does MP4033GS-Z achieve primary-side current regulation without an optocoupler?

It uses proprietary real-current-control: the internal multiplier shapes a sinusoidal reference from the MULT pin signal, which is compared against the sensed primary current (via S pin). LED current is calculated as I_LED ≈ (V_REF × N) / (2 × R_s), where V_REF = 0.414 V, N is transformer turns ratio, and R_s is sense resistor value-enabling ±3% accuracy without secondary feedback.

Can MP4033GS-Z be used in non-isolated buck-derived topologies?

No. MP4033GS-Z is designed exclusively for isolated topologies (flyback, forward) where ZCD pin monitors auxiliary winding voltage for zero-current switching and OVP. Its real-current-control algorithm and protection architecture assume galvanic isolation; non-isolated use violates safety certification and invalidates OVP, SCP, and ZCD functions.

What is the role of the DAMP pin, and how is it implemented?

The DAMP pin drives an external MOSFET to suppress high-frequency ringing at the drain node during MOSFET turn-off. This reduces EMI emissions and prevents false triggering of ZCD or OVP circuits. A typical implementation uses a 20 V-rated small-signal MOSFET (e.g., DMN2004K) with 10 Ω gate resistor, connected between DAMP and GND, with source tied to main MOSFET drain.

Does MP4033GS-Z require external components for PFC compliance?

No external PFC components are required. Active PFC is implemented internally via the multiplier circuit driven by the MULT pin's rectified line voltage signal. The IC shapes input current into a near-sinusoid aligned with voltage, achieving >0.9 power factor across 90–264 VAC input range without boost inductors, diodes, or controllers.

How does thermal fold-back work with the NTC pin?

The NTC pin accepts a thermistor divider; when ambient temperature rises, NTC resistance drops, lowering the pin voltage. At VL_NTC = 0.80 V, fold-back begins; at VH_NTC = 1.20 V, current is reduced to 50%. The IC continuously scales LED current between these thresholds, preventing thermal runaway and extending LED lifetime by up to 25,000 hours in high-temp environments.

Is MP4033GS-Z pin-compatible with other MP403x variants?

MP4033GS-Z (SOIC-8) shares identical pinout with MP4032GS-Z but differs functionally: MP4033 adds DIM and NTC pins, while MP4032 omits them. MP4033GK-Z (MSOP-10) and MP4033GSE-Z (SOIC-14) add NC pins and relocate NTC/DIM-so direct PCB replacement is not possible without layout revision.