Diodes Incorporated AL5809-40P1-7

Overview

AL5809-40P1-7 from Diodes Incorporated is a two-terminal constant-current linear LED driver in PowerDI123 package, delivering 40mA ±5% regulated current over -40°C to +125°C ambient, with 2.5V to 60V input-output voltage range and 20ppm/°C temperature drift. It supports both high-side and low-side LED string configurations for offline LED lamps and signage.

For engineers reviewing the AL5809-40P1-7 datasheet, AL5809-40P1-7 pinout, AL5809-40P1-7 application, or AL5809-40P1-7 equivalent, key selection criteria include its fixed 40mA output, 60V floating-voltage rating between IN/OUT, thermal shutdown at +165°C, and compatibility with PWM dimming via external MOSFET switching at the OUT terminal.

Technical Context

The AL5809-40P1-7 integrates an internal precision current mirror and low-dropout regulator to maintain stable 40mA output across 2.5–60V V_IN-OUT, with line regulation of ≤1% over full voltage range. Its floating ground architecture enables direct series connection with LED strings without reference to system ground.

It features thermal shutdown activation at +165°C with +30°C hysteresis, and supports PWM dimming by externally switching the OUT pin to ground using a MOSFET, requiring minimum on/off pulse widths of 500µs each. No external resistor is needed-current setting is factory-trimmed.

Key Specifications

Pinout & Package

AL5809-40P1-7 uses the PowerDI123 surface-mount package (3.7mm × 2.8mm × 1.78mm), thermally optimized with exposed cathode pad for PCB heat sinking. Pin 1 (IN) and Pin 2 (OUT) are electrically symmetrical but functionally assigned per circuit topology.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL5809-40S1-7, the -40P1-7 enables 3.4× higher power handling and reliable operation in thermally demanding fixtures; versus NSI45020T1G, it provides double the current, 33% higher voltage tolerance, and tighter thermal shutdown control - critical for long-life AC-connected lighting.

Availability

AL5809-40P1-7 is available at Aetrix Electronics and suitable for offline LED lamps, LED signs, and white goods requiring stable component supply, extended temperature operation, and RoHS-compliant manufacturing.

Supply support for AL5809-40P1-7 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 analog ICs, specializing in high-reliability power management, signal integrity, and LED solutions for industrial and consumer markets.

The AL5809 product line delivers cost-optimized, resistorless constant-current drivers for AC/DC and DC/DC LED lighting systems - designed specifically for simplicity, thermal robustness, and wide-input-voltage operation in space-constrained fixtures.

FAQ

Can AL5809-40P1-7 be used in high-side configuration with AC input?

Yes - its 60V floating voltage rating between IN and OUT pins allows direct series placement with rectified AC waveforms. When used in high-side mode, the IN pin connects to the rectified DC bus and OUT to the LED anode, enabling operation across full AC peaks without additional isolation or clamping. Thermal derating must be applied based on average power dissipation and PCB copper area.

What is the minimum LED string voltage required for stable regulation?

The AL5809-40P1-7 requires ≥2.5V across IN–OUT to initiate regulation, so the LED string forward voltage must be at least 2.5V below the supply voltage. For example, with a 12V supply, the maximum allowable LED string voltage is 9.5V (e.g., three 3.2V white LEDs). Below this threshold, current drops nonlinearly and regulation ceases.

How does thermal shutdown behave under continuous overload?

Thermal shutdown activates at +165°C junction temperature and holds OFF until junction cools by +30°C (to +135°C), then automatically recovers. During shutdown, the device draws <10µA - preventing thermal runaway. Recovery time depends on PCB thermal mass and ambient airflow; typical recovery is 1–3 seconds in open-air conditions with recommended 25.4mm×25.4mm copper pad.

Is PWM dimming compatible with both high-side and low-side configurations?

Yes - PWM dimming works identically in both topologies by switching the OUT pin to ground via an external N-channel MOSFET. In high-side use, the MOSFET is placed between OUT and system ground; in low-side, it is placed between OUT and LED cathode. The 500µs minimum pulse width limits usable PWM frequency to ≥200Hz for full 5–95% duty cycle range.