Monolithic Power Systems Inc. MP4000DS-LF-Z

Overview

MP4000DS-LF-Z from Monolithic Power Systems is a constant-current LED driver controller for offline high-brightness white LED applications, implementing boundary conduction mode (BCM) with zero-current turn-on, 300mV CS reference voltage, 110kHz max switching frequency, and hiccup-mode short-circuit protection. It drives an external MOSFET in a floating buck topology for AC/DC LED lighting systems up to 12W.

For engineers reviewing the MP4000DS-LF-Z datasheet, MP4000DS-LF-Z pinout, MP4000DS-LF-Z application, or MP4000DS-LF-Z equivalent, key selection criteria include BCM operation for high efficiency, external MOSFET control flexibility, dual PWM/DC burst dimming interface, low 0.9mA operating current, and SOIC8 thermal performance under industrial ambient conditions.

Technical Context

The MP4000 operates in boundary conduction mode using zero-current detection at the DRIVE pin via MOSFET drain dv/dt sensing, eliminating freewheeling diode reverse recovery loss and enabling soft MOSFET turn-on. Peak current regulation is achieved through a 300mV ±15mV CS reference voltage with external sense resistor feedback.

Burst dimming is implemented via either DC voltage (0–2.4V on DIM) or external PWM (100Hz–2kHz), with BOS pin programmable via capacitor for DC mode or 300kΩ resistor for PWM mode. UVLO activates at 7.4V rising threshold with 1V hysteresis, and thermal shutdown triggers at 150°C with 30°C hysteresis.

Key Specifications

Pinout & Package

MP4000DS-LF-Z is housed in an industry-standard SOIC8 package (5.00 mm × 6.20 mm, 1.27 mm pitch), rated for -40°C to +85°C ambient operation and 1.3 W power dissipation at T_A = 25°C (θ_JA = 96°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP4001DS-LF-Z, MP4000DS-LF-Z offers greater design flexibility with external MOSFET selection and higher voltage/current scalability; versus AL1676-8S, it delivers superior dimming fidelity, efficiency, and fault protection at the cost of slightly higher system complexity.

Availability

MP4000DS-LF-Z is available at Aetrix Electronics and suitable for residential LED downlights, commercial track lighting, and industrial panel-mount LED fixtures requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for MP4000DS-LF-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 mixed-signal ICs for power management, LED lighting, and motor drive applications.

The MP4000 belongs to MPS's offline LED driver controller product line, designed specifically for high-efficiency, thermally robust, and dimmable AC/DC LED lighting solutions targeting residential, commercial, and industrial markets.

FAQ

What is the recommended inductor value for MP4000DS-LF-Z in a 12 W, 350 mA LED application?

For 90–265 VAC input, 350 mA LED current, and 10–40 V output, MPS recommends a 680 µH inductor with ≥1.5 A saturation current. Inductor value is calculated per L = (V_SUPPLY – V_OUT) × V_OUT / (2 × f_S × I_LED × V_SUPPLY), targeting 50–80 kHz switching frequency to stay within the 30–110 kHz BCM range and avoid DCM.

Can MP4000DS-LF-Z operate without a valley-fill PFC circuit?

Yes. The MP4000DS-LF-Z functions with or without valley-fill PFC. It regulates LED current independently of input stage topology. However, omitting valley-fill reduces power factor to ~0.5–0.6, failing regulatory requirements like ENERGY STAR or IEC 61000-3-2 for >5 W lighting products.

How does the BOS pin affect dimming behavior in PWM vs. DC mode?

In PWM mode, BOS is pulled to GND via 300 kΩ to establish a 1.2 V reference for DIM logic thresholds; in DC mode, a capacitor from BOS to GND sets burst frequency (f_DIM ≈ I_BOS / C_BOS). Open or misconfigured BOS causes erratic or disabled dimming-never leave it floating.

What is the purpose of the TST pin, and how must it be connected?

The TST pin is a factory test terminal with no functional role in application circuits. Per MPS datasheet Section 4, it must be externally connected to GND. Leaving TST unconnected may cause undefined behavior or failure to start due to internal floating node conditions.

Does MP4000DS-LF-Z support analog (0–10 V) dimming directly?

No. MP4000DS-LF-Z accepts only 0–2.4 V DC on the DIM pin for linear burst dimming. To interface with standard 0–10 V dimmers, an external resistive divider (e.g., 270 kΩ + 82 kΩ) is required to scale 10 V down to ≤2.4 V while maintaining dimmer load compliance.

What happens if the CS sense resistor fails open-circuit?

An open CS resistor disables current regulation and triggers immediate hiccup-mode shutdown: the IC detects loss of feedback, ceases switching after ~1.7 ms, waits 1.7 ms, then retries. This cycle repeats indefinitely until fault is corrected, preventing MOSFET destruction or thermal runaway.

Is MP4000DS-LF-Z qualified for automotive temperature grade (-40°C to +125°C)?

No. MP4000DS-LF-Z is specified for industrial grade only: -40°C to +85°C ambient. Its thermal shutdown triggers at 150°C junction, but SOIC8 package derating and internal UVLO/OTP thresholds are not validated for 125°C ambient. For automotive, consider AEC-Q100-qualified alternatives like MPQ4425HGJ.