Monolithic Power Systems Inc. MP4050GS

Overview

MP4050GS from Monolithic Power Systems is a non-isolated, constant-current LED driver IC with an integrated 500V/7.2Ω MOSFET, designed for AC/DC LED bulk replacement in 85–265VAC input systems. It delivers stable 115mA output current at 40V with audible-noise-free operation above 22kHz switching frequency and includes open/short lamp protection, thermal shutdown, and internal high-voltage startup current source.

For engineers reviewing the MP4050GS datasheet, MP4050GS pinout, MP4050GS application, or MP4050GS equivalent, key selection criteria include its 500V drain rating, 0.45V peak current limit threshold, VCC UVLO hysteresis (0.24V typ), PRO pin OVP/UVP thresholds (2.0V/0.39V), and SOIC8 thermal resistance (θJA = 96°C/W).

Technical Context

The MP4050GS implements average current-mode control using internal sampling of the SOURCE pin voltage to regulate LED current via a 0.194V feedback reference. Its internal 500V MOSFET operates in discontinuous conduction mode (DCM) by default, with minimum off-time (4.7μs) and maximum on-time (25μs) limits enforcing ≥22kHz operation to suppress audible noise.

Protection logic is tightly coupled to the PRO pin: open-lamp detection triggers when PRO exceeds 2.0V during MOSFET off-time, while short-lamp detection activates below 0.39V; both initiate hiccup-mode restart with VCC discharge to 2.35V followed by recharging via the internal HV current source.

Key Specifications

Pinout & Package

MP4050GS is housed in an SOIC-8 package with exposed pad for thermal enhancement. Pin functions are validated per MPS datasheet Rev.1.03: Pins 1–4 and 7 are active; pins 5, 6, and 8 are no-connect.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP4050GS, MP4051GS offers higher voltage headroom and lower conduction loss for extended lifetime in harsh AC environments, while BP5758D trades comprehensive protection for lower BOM cost and simpler layout-making MP4050GS the balanced choice for reliability-critical, mid-power LED replacements.

Availability

MP4050GS is available at Aetrix Electronics and suitable for LED bulk lamp replacement, industrial panel lighting, and automotive interior accent lighting requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP4050GS 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 MP4050 product line targets cost-sensitive, non-isolated LED driver applications demanding high integration, wide input range, and robust fault protection-enabling compact, efficient replacements for legacy lighting technologies.

FAQ

What is the maximum output power achievable with MP4050GS in SOIC8 package at 265VAC input?

At 265VAC input and 90°C ambient, the SOIC8 MP4050GS supports up to 375mA × 40V = 15W in universal-input buck configuration before thermal shutdown activates. Derating is required above 75°C ambient; full-rated 115mA output is guaranteed from –40°C to +125°C junction temperature.

Can MP4050GS operate from a DC input source, and what is the valid DC voltage range?

Yes-MP4050GS supports DC input from 12V to 375V, verified per Absolute Maximum Ratings (Drain-to-Source ≤500V). Operation below 12V is not functional due to insufficient energy for VCC startup; above 375V risks exceeding internal MOSFET breakdown voltage under transient conditions.

How does the PRO pin detect open and short lamp conditions, and what external components are required?

PRO pin voltage is sampled during MOSFET off-time: >2.0V indicates open lamp (high impedance), <0.39V indicates short lamp (low impedance). External components include R2/R3 feedback divider (e.g., 10kΩ + 200kΩ) and a 30pF ceramic decoupling capacitor from PRO to GND for noise immunity.

What is the purpose of the internal 200ns leading edge blanking (LEB), and how does it affect design?

The 200ns LEB disables the current comparator immediately after MOSFET turn-on to ignore parasitic drain-source voltage spikes caused by layout inductance. This prevents false current-limit triggering and ensures accurate peak current control-no external snubber or layout mitigation is needed beyond standard high-frequency practices.

Does MP4050GS support analog or PWM dimming, and how is it implemented?

MP4050GS supports analog dimming via PRO pin voltage modulation: applying 0.5–1.8V to PRO scales output current linearly from 0% to 100%. PWM dimming is implemented externally by pulsing the VCC supply-ensuring full current regulation during ON periods and complete shutdown during OFF periods with no residual leakage.

What thermal considerations apply when using MP4050GS in TSOT23-5 versus SOIC8 packages?

SOIC8 offers θJA = 96°C/W vs. TSOT23-5's 100°C/W-yielding ~4% better thermal performance at same PCB copper area. For >3W output, SOIC8 is strongly preferred; TSOT23-5 requires aggressive copper pour and thermal vias to avoid derating above 70°C ambient. Both packages share identical 150°C thermal shutdown threshold.

Is an external freewheeling diode mandatory, and what specifications must it meet?

Yes-an external ultrafast freewheeling diode is mandatory. It must withstand ≥500V reverse voltage (e.g., WUGC10JH), conduct ≥2× output current (e.g., 230mA for 115mA design), and exhibit ≤75ns reverse recovery time to minimize switching losses and EMI in DCM operation.