Diodes Incorporated AL5809-15S1-7

Overview

AL5809-15S1-7 from Diodes Incorporated is a two-terminal constant-current linear LED driver in SOD-123 package, delivering 15mA ±5% regulated current over -40°C to +125°C, with 2.5V–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 instrumentation illumination.

For engineers reviewing the AL5809-15S1-7 datasheet, AL5809-15S1-7 pinout, AL5809-15S1-7 application, or AL5809-15S1-7 equivalent, this part enables simplified LED current regulation without external resistors, offers thermal shutdown at +165°C, and requires attention to PCB thermal vias and ground plane area for ambient temperature derating above +85°C.

Technical Context

The AL5809-15S1-7 integrates a fixed internal current-setting resistor and precision current mirror to deliver 15mA output with ±5% tolerance across full temperature and supply range. Its floating-ground architecture allows operation with up to 60V differential between IN and OUT pins, enabling direct series connection to long LED strings in AC-coupled offline applications.

It features a low-dropout regulator powering the internal control block, minimum turn-on voltage of 2.5V, and built-in thermal shutdown with +30°C hysteresis. PWM dimming is supported via external MOSFET switching at the OUT pin, with validated 100–200Hz frequency range and 5–95% duty cycle limits.

Key Specifications

Pinout & Package

SOD-123 surface-mount package: compact 2.65mm × 1.55mm footprint with gull-wing leads, optimized for space-constrained LED modules and indicator boards. Requires thermal vias under OUT pad per Diodes' recommended layout (X=0.900mm, X1=4.050mm, Y=0.950mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL5809-15S1-7, the AL5809-15P1-7 delivers higher thermal headroom for demanding environments, while the NSI45015WT1G trades safety features for tighter initial accuracy in benign low-voltage applications.

Availability

AL5809-15S1-7 is available at Aetrix Electronics and suitable for offline LED lamps, white goods illumination, and instrumentation panels requiring stable component supply, RoHS compliance, and SOD-123 footprint compatibility.

Supply support for AL5809-15S1-7 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 ICs, specializing in high-reliability power management, signal integrity, and lighting solutions for industrial, automotive, and consumer markets.

The AL5809 product line delivers cost-effective, resistorless constant-current LED drivers targeting retrofit lighting, appliance indicators, and low-EMI instrumentation - emphasizing simplicity, thermal resilience, and regulatory compliance.

FAQ

What is the maximum LED string voltage that AL5809-15S1-7 can drive?

The AL5809-15S1-7 supports up to 60V differential between IN and OUT pins. For a 15mA string, maximum LED chain voltage equals VIN − 60V. With 230VAC rectified (≈325V peak), it can drive ~10 white LEDs (3.2V each) if VIN is clamped to ≤385V. Always verify junction temperature remains ≤+125°C using θJA = 278.42°C/W and actual PCB layout.

Can AL5809-15S1-7 be used in PWM dimming circuits?

Yes - connect an external N-channel MOSFET between OUT and ground, drive its gate with 100–200Hz PWM, and ensure minimum pulse widths ≥500µs. The device maintains regulation during ON periods and fully disables current during OFF periods. Avoid frequencies below 100Hz to prevent visible flicker and above 200Hz to maintain dimming linearity per Figure 5.

How does thermal shutdown behave during overload conditions?

When junction temperature reaches +165°C, AL5809-15S1-7 shuts down current flow and remains off until temperature drops by ≥30°C (to ≤+135°C), then automatically recovers. This hysteresis prevents oscillation during marginal thermal conditions. Recovery time depends on PCB thermal mass and airflow - typically 1–5 seconds in still air on standard FR-4.

Is AL5809-15S1-7 compatible with high-side and low-side configurations simultaneously?

No - the device must be wired exclusively as either high-side (IN to supply, OUT to LED anode) or low-side (IN to LED cathode, OUT to ground). Simultaneous use violates pin voltage ratings and risks latch-up. However, the same part number supports either topology via PCB layout change - no redesign of schematic or firmware required.