Diodes Incorporated AL9901FDF-13

Overview

AL9901FDF-13 from Diodes Incorporated is a universal high-voltage PWM LED driver IC with integrated 650V/2A MOSFET, designed for offline LED lamps operating directly from rectified AC mains (85–305VAC). It delivers constant current up to 180mA with ±5% sense tolerance, supports linear and PWM dimming, and achieves >90% efficiency in buck topology configurations.

For engineers reviewing the AL9901FDF-13 datasheet, AL9901FDF-13 pinout, AL9901FDF-13 application, or AL9901FDF-13 equivalent, this device is selected for high-reliability, thermally efficient LED lighting where input voltage range, internal power switch integration, and dual dimming control are critical design requirements.

Technical Context

The AL9901FDF-13 implements a fixed-frequency or fixed-off-time current-mode controller using an internal 650V vertical DMOS power MOSFET. Its regulation relies on peak-current sensing via the CS pin with a nominal 250mV threshold, blanked for 160–440ns to reject switching noise.

It integrates a 7.5V LDO regulator (capable of sourcing 1mA) that powers internal circuitry and eliminates external start-up resistors. UVLO (6.4–7.2V) ensures safe startup, while thermal shutdown activates at +150°C with +50°C hysteresis.

Key Specifications

Pinout & Package

AL9901FDF-13 is housed in a thermally enhanced U-DFN6040-12 package (6.0mm × 4.0mm × 0.75mm) with two exposed pads: EP1 (drain connection) and EP2 (substrate/GND connection). The package supports high-voltage spacing compliance and low thermal impedance when mounted on ≥25mm² 1oz copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL9901FDF-13, AL9901SP-13 trades thermal performance for regulatory compliance in SO-16, while AL9910BQ-13 improves power density and precision but requires layout revision due to different pinout and biasing.

Availability

AL9901FDF-13 is available at Aetrix Electronics and suitable for LED offline lamps, signage lighting, and flat-panel backlighting requiring stable component supply, RoHS-compliant packaging, and high-voltage operational reliability.

Supply support for AL9901FDF-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and ICs, specializing in power management, signal integrity, and lighting solutions for industrial, consumer, and automotive markets.

The AL9901 product line delivers high-voltage LED driver ICs with integrated power switches, targeting cost-sensitive, space-constrained AC-powered lighting applications requiring high efficiency and robust thermal performance.

FAQ

What is the maximum LED string voltage supported by AL9901FDF-13?

The AL9901FDF-13 does not regulate output voltage directly-it regulates current in buck topology. Maximum LED string voltage depends on input voltage and duty cycle constraints. For stable operation, input DC must exceed twice the LED string forward voltage (e.g., ≥60V for 30V string), and peak drain voltage must stay below 650V. Typical designs support up to 18× 3V LEDs (54V) from 264VAC input.

Can AL9901FDF-13 operate in isolated flyback topology?

Yes-the AL9901FDF-13 supports isolated topologies including flyback. Its current-mode control and internal MOSFET allow energy transfer during the off-cycle via transformer secondary winding. External components (transformer, optocoupler feedback, snubber) must be added; the IC regulates peak primary current, not secondary voltage.

How does linear dimming interact with PWM dimming on AL9901FDF-13?

LD and PWM pins operate independently: LD adjusts the current-sense threshold (45–250mV), setting maximum current level, while PWM enables/disables switching at user-defined duty cycle. Combining both allows coarse current scaling (LD) plus fine-grained brightness modulation (PWM), enabling smooth 0.1%–100% dimming range without flicker.

What thermal derating applies to AL9901FDF-13 in U-DFN6040-12 package?

In U-DFN6040-12, AL9901FDF-13 has θ_JA = 65°C/W on 25mm² 1oz copper. Power dissipation must be limited to 1W at +25°C ambient, derating by 10mW/°C above +25°C. At +105°C ambient, max continuous dissipation drops to 200mW. Thermal vias under EP1/EP2 and ≥500mm² copper pour reduce junction temperature by up to 25°C.