Monolithic Power Systems Inc. MP46885DN-LF

Overview

MP46885DN-LF from Monolithic Power Systems is a high-voltage step-down LED driver IC integrating a 80V-rated high-side MOSFET, delivering up to 500mA constant current with ±5% accuracy, 2MHz switching frequency, and 20kHz PWM dimming capability-designed for automotive headlight modules and industrial high-bay lighting.

For engineers reviewing the MP46885DN-LF datasheet, MP46885DN-LF pinout, MP46885DN-LF application, or MP46885DN-LF equivalent, key selection criteria include input voltage range (4.5–80V), hysteretic current-mode control architecture, SOIC8E exposed-pad thermal performance, and dedicated DIM/EN logic thresholds for robust system integration.

Technical Context

The MP46885DN-LF implements adaptive hysteresis current-mode control: FB pin thresholds dynamically shift between 185mV (low) and 215mV (high) to maintain 200mV average sensing voltage, enabling precise LED current regulation without external compensation. Its internal 1.0A peak current limit and integrated high-side switch eliminate external gate drivers.

Thermal shutdown activates at 150°C with 20°C hysteresis; UVLO engages at 4.0V rising threshold (3.65V falling); and short-circuit protection disables the switch within 10µs if FB remains below 190mV during conduction-ensuring fault tolerance in open-load or LED-string-short conditions.

Key Specifications

Pinout & Package

MP46885DN-LF is housed in an SOIC-8 with exposed thermal pad (SOIC8E), optimized for surface-mount assembly and thermal dissipation via PCB copper area connected to the exposed pad (θ_JA = 50°C/W, θ_JC = 10°C/W on 4-layer board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage LED driver applications.

Compared with LT3474EMS#TRPBF and TPS92630QPWPRQ1, MP46885DN-LF delivers higher efficiency (95% vs. 90%) at 2MHz switching, eliminates compensation components, and provides dedicated dimming logic-making it optimal for cost-sensitive, thermally constrained, non-safety-critical high-brightness LED systems.

Availability

MP46885DN-LF is available at Aetrix Electronics and suitable for automotive lighting, industrial high-bay fixtures, emergency signage, and UV-C sterilization modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MP46885DN-LF 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, serving automotive, industrial, and consumer markets since 1997.

The MP46885 belongs to MPS's high-voltage LED driver product line, engineered specifically for efficient, compact, and thermally robust constant-current regulation in harsh-environment lighting applications where input voltage variability and reliability are critical.

FAQ

What is the maximum recommended LED string voltage for MP46885DN-LF?

The MP46885DN-LF does not regulate output voltage-it regulates LED current. The maximum sustainable LED string voltage equals VIN minus the forward drop across the Schottky rectifier and inductor DCR. With 80V max VIN and typical 0.4V diode drop, strings up to 79.6V are feasible, but practical design limits to ≤75V to maintain margin for transients and thermal derating.

Can MP46885DN-LF operate without an external bootstrap diode?

Yes-MP46885DN-LF integrates a bootstrap regulator that charges the BST capacitor from VIN. An external diode (e.g., BAT54) is only recommended when VIN ≤5V, V_OUT/V_IN >65%, or switching frequency exceeds 1.5MHz to improve gate drive stability and efficiency.

How is LED current accuracy affected by temperature?

MP46885DN-LF maintains ±5% LED current accuracy over –40°C to +125°C junction temperature, verified by design and characterization. This includes compensation for R_DS(ON) drift, FB comparator offset variation, and internal reference stability-all factored into the adaptive hysteresis thresholds.

What layout practices minimize EMI in MP46885DN-LF designs?

Place C_IN, the Schottky diode, and MP46885DN-LF (VIN/SW/PGND) in a tight loop with short, wide traces; route FB away from noisy power paths and beneath a ground plane; use ≥4 thermal vias under the exposed pad; and avoid routing DIM/EN traces parallel to SW or inductors to prevent coupling-induced false triggering.

Does MP46885DN-LF support analog dimming via the FB pin?

No-MP46885DN-LF supports only PWM dimming via the dedicated DIM pin. Analog dimming by injecting current into FB violates the hysteretic control scheme and causes unstable regulation. For analog control, use external current-source modulation of the LED string itself, not the FB node.

What failure protections activate if the LED string opens?

Open-LED detection is not implemented. If the LED string opens, FB falls below 185mV and the high-side switch remains off indefinitely-placing the device in safe, zero-current standby. No latch-off or fault flag occurs; normal operation resumes upon string reconnection and EN/DIM assertion.

Is MP46885DN-LF RoHS compliant and halogen-free?

Yes-MP46885DN-LF carries the "-LF" suffix indicating lead-free, RoHS-compliant packaging per EU Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 3 (MSL3), with halogen-free epoxy molding compound meeting IEC 61249-2-21 standards.