Monolithic Power Systems Inc. MP4008GS-Z

Overview

MP4008GS-Z from Monolithic Power Systems is a constant-current, current-mode WLED controller for high-brightness LED backlighting and industrial lighting, supporting 9V–28V input, fixed 180kHz switching, 280mV ±1.8% feedback voltage, and fast PWM dimming with >1000:1 ratio. It drives an external MOSFET in boost or SEPIC topologies to regulate LED current via an external sense resistor.

For engineers reviewing the MP4008GS-Z datasheet, MP4008GS-Z pinout, MP4008GS-Z application, or MP4008GS-Z equivalent, key selection criteria include its 280mV precision FB threshold, SOIC-8 package thermal performance (θJA = 96°C/W), cycle-by-cycle OCP programmability via CS resistor, integrated short-LED/short-output/OTP protection, and compatibility with high-voltage LED strings up to 70V.

Technical Context

The MP4008GS-Z implements peak-current-mode control with integrated slope compensation to suppress sub-harmonic oscillation at duty cycles >0.5. Its internal error amplifier (GEA = 440 µA/V) regulates LED current by comparing the 280mV reference against the FB node voltage developed across an external R_FB.

Protection logic is fully hardware-based: VIN UVLO (8.6V rising, 600mV hysteresis), OVP (2.75V threshold on OVP pin), short-LED latch-off (FB > 580mV for 1µs), and cycle-by-cycle current limiting (V_CL = 485mV typical) with 100–300ns leading-edge blanking on CS to reject switch-node noise.

Key Specifications

Pinout & Package

MP4008GS-Z is housed in a standard SOIC-8 package (5.0mm × 6.0mm, 1.27mm pitch) with exposed pad for enhanced thermal dissipation (θ_JA = 96°C/W, θ_JC = 45°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar WLED controller applications.

Compared with LM3409MM/NOPB and TPS61165DRVR, MP4008GS-Z delivers higher current accuracy (±1.8% vs ±3%), integrated OVP/short-LED/short-output latching, and external MOSFET flexibility for >70V, >350mA applications - making it optimal for industrial and high-reliability LED systems.

Availability

MP4008GS-Z is available at Aetrix Electronics and suitable for LCD backlighting, industrial high-bay lighting, and automotive cabin lighting requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP4008GS-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 analog semiconductor company specializing in high-performance power management ICs, with design centers in the US, China, and Taiwan.

The MP4008 belongs to MPS's high-accuracy LED driver product line, engineered specifically for demanding backlighting and general illumination applications requiring tight current regulation, comprehensive fault protection, and wide-input-voltage operation.

FAQ

What is the minimum recommended input voltage before UVLO disables operation?

The MP4008GS-Z enters under-voltage lockout when VIN falls below 8.6V (rising threshold). Hysteresis is 600mV, so the device remains disabled until VIN rises above 9.2V. This ensures clean startup and prevents erratic behavior during brownout conditions in automotive or industrial 12V/24V systems.

How is LED current accuracy affected by temperature and supply variation?

LED current accuracy is maintained within ±1.8% over -40°C to +125°C junction temperature and 9V–28V input range due to the trimmed 280mV internal reference and matched internal resistors. The FB input current is limited to ±0.1µA, minimizing R_FB self-heating error and ensuring stable current regulation across operating conditions.

Can the MP4008GS-Z drive multiple parallel LED strings?

No - the MP4008GS-Z is designed for single-string constant-current regulation. Driving parallel strings would cause current imbalance due to V_F mismatch. For multi-string applications, use one MP4008GS-Z per string or select a multi-channel controller like the MPQ4425HGJ-A.

What is the purpose of the 100–300ns leading-edge blanking on the CS pin?

The blanking window prevents false overcurrent triggering caused by gate-drive-induced voltage spikes and parasitic ringing at the MOSFET source node. It ensures only the true inductor current ramp is sensed, enabling stable cycle-by-cycle current limiting even with fast-switching GaN or SiC FETs.

Does the MP4008GS-Z support analog dimming in addition to PWM?

No - the MP4008GS-Z supports only PWM dimming via the dedicated PWM pin. Analog dimming (e.g., DC voltage on FB) is not supported; attempting it disrupts regulation and may trigger short-LED protection. Brightness control must be implemented using externally generated PWM signals with defined 0.8V/1.5V logic thresholds.

How does the soft-start function prevent inrush current during startup?

During startup, the internal error amplifier's sourcing/sinking current is limited to 21µA, causing COMP voltage to rise gradually. This limits the duty cycle ramp rate, preventing sudden inductor current surge and output voltage overshoot - especially critical when driving high-capacitance LED loads or long cables.

What happens when short-circuit protection is triggered?

When short-circuit conditions are detected (OVP < 280mV, FB < 0.3×REF, COMP > 1V), GATE and COMP are immediately pulled low, and the IC latches off. Recovery requires cycling VIN power - no automatic retry - ensuring safety in persistent fault scenarios such as LED+ shorted to GND.