Monolithic Power Systems Inc. MP4027GJ-Z

Overview

MP4027GJ-Z from Monolithic Power Systems is a primary-side-control, offline LED controller in TSOT23-8 package, integrating active PFC, valley switching, NTC thermal fold-back, and PWM dimming. It delivers <2% line/load regulation, ≥0.9 power factor across universal AC input (90–264VAC), and accurate real-current control for isolated flyback and non-isolated buck-boost LED drivers up to 350mA.

For engineers reviewing the MP4027GJ-Z datasheet, MP4027GJ-Z pinout, MP4027GJ-Z application, or MP4027GJ-Z equivalent, this device supports design of compact, high-reliability LED drivers requiring no optocoupler or secondary-side feedback - with built-in OVP, SCP, OTP, brown-out protection, and auto-restart for robust operation in commercial lighting systems.

Technical Context

The MP4027GJ-Z implements proprietary real-current control using primary-side sensing via CS/ZCD, eliminating secondary feedback while maintaining ±2% LED current accuracy. Its multiplier-based PFC architecture processes the rectified AC line signal at MULT to shape input current sinusoidally, achieving ≥0.9 PF without external controllers.

Valley-switching operation is triggered by dual zero-crossing detection on CS/ZCD, minimizing MOSFET turn-on loss and diode reverse-recovery noise. The IC combines cycle-by-cycle current limiting (2.46V OCP threshold), 5.5µs minimum off-time, and 190µs auto-starter to ensure stable startup and fault recovery under short-circuit or ZCD failure conditions.

Key Specifications

Pinout & Package

MP4027GJ-Z is housed in a thermally enhanced TSOT23-8 package (2.9mm × 1.6mm × 0.85mm), optimized for high-density LED driver PCB layouts and compatible with standard SMT reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCL30001DR2G and AL1676S16-13, MP4027GJ-Z uniquely integrates NTC/PWM dual-mode dimming, valley switching, and brown-out recovery in a single TSOT23-8 package - enabling smaller, safer, and more versatile LED drivers across isolated and non-isolated topologies.

Availability

MP4027GJ-Z is available at Aetrix Electronics and suitable for commercial indoor lighting, industrial high-bay fixtures, and residential smart dimmable lamps requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MP4027GJ-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 MP4027 belongs to MPS's primary-side LED controller product line, designed specifically to eliminate optocouplers and secondary feedback in AC/DC LED drivers while delivering high PF, precise current regulation, and comprehensive protection.

FAQ

What is the purpose of the MULT pin, and how is it connected?

The MULT pin receives a scaled-down version of the rectified AC line voltage via a resistor divider, enabling the MP4027GJ-Z to perform active power factor correction and brown-out detection. It must be connected to the AC bus through a high-voltage divider (e.g., 1MΩ + 10kΩ), with optional Zener clamping for improved THD at high-line inputs. Internal circuitry uses MULT to generate a sinusoidal current reference that shapes input current waveform.

Can MP4027GJ-Z operate in non-isolated topologies, and what are the key layout considerations?

Yes - MP4027GJ-Z supports low-side and high-side buck-boost configurations. For high-side designs, the FB pin enables direct LED current sensing, but layout must isolate the feedback network from noisy switch nodes. Critical practices include placing feedback resistors adjacent to FB, minimizing trace length between CS/ZCD and sense resistor, and routing GND returns separately for analog and power sections to avoid ground bounce.

How does the NTC pin support both thermal protection and PWM dimming?

The NTC pin accepts either an NTC thermistor (for analog thermal fold-back) or a PWM signal (>200Hz) - both share the same internal comparator thresholds. When used for dimming, the high PWM level (>1.23V) sets full LED current; the low level (<0.39V) forces minimum current. A 2.2nF capacitor to GND is recommended for thermal mode but omitted for PWM mode to preserve signal edge integrity.

What protection features are implemented, and how do they behave during fault conditions?

MP4027GJ-Z integrates OVP (latched shutdown at 5.1V on CS/ZCD), SCP (5kHz frequency foldback), OTP (150°C shutdown with 25°C hysteresis), and brown-out (42ms delay before disabling COMP). All protections trigger auto-restart after VCC drops below 9.5V, ensuring recovery without manual reset - critical for unattended outdoor and industrial lighting deployments.

What is the significance of the CS/ZCD pin's dual function, and how is it configured?

CS/ZCD serves as both current-sense input (for OCP at 2.46V) and zero-current detector (triggering GATE turn-on when voltage falls below 0.295V twice per cycle). It connects to a resistor divider from the auxiliary winding via a diode. A 10pF capacitor to GND suppresses high-frequency noise, and a 1kΩ resistor between CS/ZCD and GND minimizes RC delay impact on current-sense accuracy.

Does MP4027GJ-Z require an external compensation network, and where is it connected?

Yes - a Type II compensation network (typically 10kΩ resistor + 1nF capacitor + 100pF capacitor) must be connected between COMP and GND to stabilize the current regulation loop. This network sets loop bandwidth and phase margin; incorrect values cause LED current overshoot or instability under line/load transients. The COMP pin voltage ranges from 1.5V to 4.75V during normal operation.

What is the minimum off-time, and why is it important for EMI performance?

The MP4027GJ-Z enforces a 5.5µs minimum off-time to limit maximum switching frequency, especially at low-line inputs where variable-frequency operation would otherwise push fSW beyond 200kHz. This constraint reduces high-frequency harmonics, easing EMI filter design and helping meet CISPR-15 Class B conducted emissions limits without oversized chokes or capacitors.