Monolithic Power Systems Inc. MP4068GN

Overview

MP4068GN from Monolithic Power Systems is a non-isolated, TRIAC-dimmable LED driver IC optimized for 120VAC input and up to 10W LED loads. It integrates a 500V MOSFET, achieves >0.7 power factor, delivers ±5% LED current accuracy via internal averaging feedback, and supports buck/buck-boost topologies in residential A19/GU10 lamp designs.

For engineers reviewing the MP4068GN datasheet, MP4068GN pinout, MP4068GN application, or MP4068GN equivalent, this device is selected for cost-sensitive, small-form-factor, off-line LED lighting where flicker-free dimming, thermal foldback, and single-winding inductor simplicity are critical design requirements.

Technical Context

The MP4068GN implements MPS' proprietary hybrid operation mode-dynamically switching between CCM and DCM across the AC half-cycle-to maintain TRIAC latching/holding current while sustaining high power factor (>0.7) and smooth dimming down to low duty cycles. Its internal HV regulator draws directly from the HV pin to enable fast start-up without external bias winding.

Current regulation uses an internal sample-and-hold circuit comparing VFB to a 0.195V reference; output current is set by I_OUT = 0.195V / R_SENSE. Thermal protection initiates de-rating at 145°C and triggers shutdown at 160°C with 50°C hysteresis, ensuring flicker-free operation under high ambient conditions.

Key Specifications

Pinout & Package

MP4068GN is packaged in SOIC-8 EP (exposed pad), offering 2.6W continuous power dissipation at +25°C and θ_JA = 48°C/W on a 4-layer PCB-optimized for thermally constrained LED lamp modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TRIAC-dimmable, non-isolated LED driver applications.

Compared with MP4067GN and BP57722, MP4068GN uniquely combines integrated 500V MOSFET, hybrid dimming mode, and graded thermal foldback-making it the only option that simultaneously satisfies 120VAC surge immunity, smooth 10–100% dimming, and flicker-free operation in thermally constrained lamps.

Availability

MP4068GN is available at Aetrix Electronics and suitable for residential LED retrofit bulbs, commercial downlights, and architectural accent lighting requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MP4068GN 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 two decades of leadership in DC/DC converters, LED drivers, and motor drivers.

The MP4068GN belongs to MPS's TRIAC-dimmable LED driver product line, engineered specifically for cost-sensitive, non-isolated 120VAC lighting applications where integration, thermal resilience, and dimming fidelity are prioritized over isolation.

FAQ

What is the maximum LED string voltage supported by MP4068GN?

The MP4068GN supports output voltages up to 50V in typical buck applications, as validated in the design example (VIN=120VAC, VOUT=50V, IOUT=160mA). With buck-boost topology, output can exceed input-up to ~65V depending on inductor selection and OVP threshold configuration-but 50V is the recommended maximum for reliable OVP margin and thermal performance.

Does MP4068GN require an external MOV or TVS for 120VAC surge protection?

No. The integrated 500V MOSFET enables the MP4068GN to pass 500V surge testing per IEC 61000-4-5 without external MOV or TVS components-reducing BOM count and improving reliability in cost-sensitive lamp designs.

How does MP4068GN achieve flicker-free operation at high ambient temperatures?

It implements graded LED current foldback starting at 145°C junction temperature, reducing output current progressively to limit power dissipation. This prevents abrupt thermal shutdown cycling and maintains steady light output-even in enclosed fixtures where ambient temperatures reach 65°C.

Can MP4068GN operate with both leading-edge and trailing-edge TRIAC dimmers?

Yes. Its hybrid operation mode actively maintains TRIAC latching and holding current across the AC half-cycle, enabling compatibility with standard leading-edge (TRIAC) dimmers. Trailing-edge (ELV) dimmer compatibility is not guaranteed and requires validation per specific dimmer model and load capacitance.

What is the purpose of the NC pins (5, 6, 8) on MP4068GN?

Pins 5, 6, and 8 are unconnected (NC) and internally unbonded. They must remain floating-no trace, pad, or solder connection should be made. Connecting them risks parasitic coupling, EMI degradation, or unintended latch-up due to internal die structure.

Is MP4068GN compatible with both buck and buck-boost topologies?

Yes. The datasheet provides verified schematics and design guidelines for both configurations. Buck topology is preferred for lower output voltages (<40V); buck-boost allows higher output voltages and better dimming linearity at low input phases but requires careful layout to manage reverse recovery stress on the freewheeling diode.

What is the minimum recommended sense resistor value for CS pin operation?

The CS pin triggers MOSFET turn-off at 0.46V (typ). For a 160mA LED current, R_SENSE = 0.195V / 0.16A ≈ 1.22Ω. Minimum practical value is ~1Ω (1% tolerance, 0805 size), ensuring sufficient signal-to-noise ratio and avoiding excessive power loss (>75mW at 160mA).