Monolithic Power Systems Inc. MP4050AGS-Z

Overview

MP4050AGS-Z from Monolithic Power Systems is a non-isolated, constant-current LED driver IC with an integrated 500V/8Ω MOSFET, designed for AC/DC and DC/DC high-brightness LED bulb replacement. It delivers precise 115mA output current from universal 85–265VAC input, operates above 22kHz to suppress audible noise, and features thermal foldback at 145°C and shutdown at 160°C for robust thermal management in compact lighting modules.

For engineers reviewing the MP4050AGS-Z datasheet, MP4050AGS-Z pinout, MP4050AGS-Z application, or MP4050AGS-Z equivalent, key selection criteria include its integrated HV MOSFET, VCC UVLO hysteresis (0.24V), PRO open-LED detection threshold (2.0V), minimum off-time (4.7μs), and SOIC-8 package thermal resistance (θJA = 96°C/W).

Technical Context

The MP4050AGS-Z implements a high-side buck topology with internal averaging current feedback using a SOURCE-sensed resistor to regulate LED current via VREF = 0.196V. Its control loop enforces a minimum switching frequency of 22kHz through peak-current reduction, preventing audible noise while maintaining DCM operation under typical loads.

Thermal protection operates in two stages: current foldback begins at TJ = 145°C to slow temperature rise, and full shutdown occurs at TJ = 160°C with auto-restart hysteresis (THYS = 50°C). Open LED protection uses the PRO pin with 2.0V threshold and 32μs comparator time constraint, triggering hiccup-mode recovery.

Key Specifications

Pinout & Package

MP4050AGS-Z is housed in a SOIC-8 package with exposed pad for enhanced thermal dissipation (θJC = 45°C/W). The package supports surface-mount assembly and meets RoHS, halogen-free, and lead-free requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant-current LED driver applications.

Compared with MP4050AGS-Z, MP4050AGJ-Z trades thermal performance for size reduction, while MPQ4050AGS-Z adds automotive qualification without altering functionality - enabling drop-in use where reliability certification is mandatory.

Availability

MP4050AGS-Z is available at Aetrix Electronics and suitable for smart residential bulbs, industrial panel lighting, and commercial downlight modules requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for MP4050AGS-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 design centers in the US, China, and Taiwan.

The MP4050A product line targets cost-sensitive, non-isolated LED lighting applications - delivering integrated HV switching, thermal resilience, and minimal external components for rapid, low-risk bulb and fixture design.

FAQ

What is the maximum recommended LED string voltage for MP4050AGS-Z?

The MP4050AGS-Z supports output voltages up to 40V in typical applications, as validated in the datasheet's 13-LED series configuration. Its 500V MOSFET withstands input surges, but sustained output voltage must remain below the minimum input voltage minus diode drop to ensure sufficient duty cycle margin - typically limiting practical string voltage to ≤40V at 230VAC input.

Can MP4050AGS-Z operate from a pure DC input?

Yes - MP4050AGS-Z is explicitly rated for both AC/DC and DC input operation. With DC input, the internal HV current source charges VCC from the DRAIN pin, and the device regulates LED current identically. Minimum DC input must exceed VOUT + VF(diode) + ILED × RS to maintain regulation, typically ≥45V for a 40V LED string.

How does the PRO pin detect open LED conditions?

The PRO pin monitors voltage across the LED string during MOSFET off-time. When the internal MOSFET turns off, the freewheeling diode conducts and PRO rises toward input voltage. If PRO exceeds 2.0V for >32μs, the OVP comparator triggers hiccup-mode shutdown - discharging VCC to 2.35V, then restarting via the HV current source after recovery.

What is the purpose of the minimum off-time limit?

The 4.7μs minimum off-time limit ensures stable DCM operation and prevents sub-harmonic oscillation at light loads. During start-up, it gradually decreases from 16.45μs over 96 cycles (32 cycles × 3 steps) to enable soft-start - limiting inrush current and preventing transformer saturation in buck-derived topologies.

Does MP4050AGS-Z require an external VCC capacitor?

Yes - a 4.7μF ceramic or electrolytic capacitor must be placed between VCC and GND. This capacitor stores energy for control circuitry during MOSFET on-time and stabilizes VCC during transients. Its value directly impacts restart timing after faults and must be selected per the equation t_RESTART = (V_CCNOR − V_CCPRO) × C_VCC / 18μA + (V_CCOFF − V_CCPRO) × C_VCC / 5mA.

Is MP4050AGS-Z compatible with TRIAC dimmers?

No - MP4050AGS-Z lacks phase-cut dimming interface circuitry and is not designed for leading-edge or trailing-edge dimmer compatibility. It delivers fixed constant current; dimming requires external PWM signal injection into the PRO or SOURCE node, or use of a separate dimmable controller stage upstream.

What PCB layout practices improve thermal performance?

Maximize copper area connected to the DRAIN pin (static HV node) to act as a heatsink, keep the SOURCE-GND sense resistor loop extremely short to minimize noise coupling, and place the VCC and PRO decoupling capacitors within 2mm of their respective pins. The SOIC-8 exposed pad must be soldered to a thermal pad with ≥4 thermal vias to inner ground planes.