Diodes Incorporated AL5802EV1

Overview

AL5802 from Diodes Incorporated is a linear-mode current sink LED driver IC integrating dual NPN transistors in SOT26 (SC74R) package, delivering 20–120 mA LED current with ±5% typical accuracy via external REXT resistor, 0.65 V reference voltage, and 0.8–30 V open-collector output voltage range - used in LED signage backlighting and industrial status indicators.

For engineers reviewing the AL5802 datasheet, AL5802 pinout, AL5802 application, or AL5802 equivalent, key selection criteria include thermal derating at >85°C ambient, PWM dimming via EN/BIAS pins, negative temperature coefficient current reduction, and compatibility with 5–24 V supply rails without inductors or switching components.

Technical Context

The AL5802 implements a two-transistor linear current regulation architecture: Q1 acts as a precision V_BE-referenced current sense element (V_BE = 0.65 V), while Q2 operates as an adjustable linear pass transistor controlled by Q1's base drive. The internal pre-biased Q2 includes integrated 7–13 kΩ input resistance for stable biasing.

It supports dual PWM dimming paths - low-impedance voltage drive on BIAS pin (Pin 2) or open-collector/open-drain switching on EN pin (Pin 3) - enabling microcontroller-compatible 400 Hz+ dimming without external level-shifting. Thermal protection is passive, relying on inherent negative temperature coefficient of V_BE to reduce I_LED above +85°C ambient.

Key Specifications

Pinout & Package

SOT26 (SC74R) package: 6-pin, small-outline transistor with exposed copper pad for thermal conduction; footprint compatible with standard 0.95 mm × 1.60 mm pad layout per Diodes Inc. recommended land pattern.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL5809-12 and NSI45020AZT1G, the AL5802 uniquely balances adjustable current (20–120 mA), dual PWM interface flexibility, and thermal robustness on compact copper PCBs - making it optimal for mid-range LED strings requiring field-tunable brightness and automotive-grade reliability.

Availability

AL5802 is available at Aetrix Electronics and suitable for LED signage backlighting, industrial status indicators, automotive interior lighting, and appliance control panel LEDs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AL5802 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 semiconductor company specializing in discrete, analog, and mixed-signal devices, with design centers in Asia, Europe, and the U.S., serving industrial, consumer, computing, and automotive markets.

The AL5802 belongs to Diodes' linear LED driver product line, engineered for cost-effective, inductor-free constant-current driving of low-to-mid power LEDs in space-constrained and thermally demanding environments.

FAQ

What is the maximum continuous LED current the AL5802 can deliver?

The AL5802 supports up to 120 mA continuous LED current under recommended operating conditions: ambient temperature ≤ +85°C, 25 mm × 25 mm 2 oz copper PCB, and V_OUT ≤ 12 V. At higher voltages or temperatures, current must be reduced per the derating curve in DS35516 Rev. 10–2, page 5, to maintain junction temperature below +150°C.

Can the AL5802 drive multiple LEDs in series?

Yes - the AL5802 can drive a single LED or a series string, provided the total forward voltage (V_F) of the string remains ≤ (V_CC − 0.65 V). For example, with a 12 V supply and 3× white LEDs (V_F ≈ 3.2 V each), total V_F = 9.6 V leaves 1.75 V headroom across Q2, well within its 0.8–30 V output compliance range.

How does the AL5802 achieve thermal protection without external components?

The AL5802 leverages the inherent negative temperature coefficient of its internal NPN transistor's V_BE. As junction temperature rises, V_BE(Q1) decreases, reducing the voltage across R_EXT and thus lowering I_LED automatically - providing passive foldback starting near +85°C without sensors, resistors, or control logic.

Is the AL5802 suitable for automotive applications?

The commercial-grade AL5802 meets JEDEC high-reliability standards and operates from −40°C to +125°C, but is not AEC-Q101 qualified. For automotive use, Diodes offers the pin-compatible AL5802WQ (Q-suffix), manufactured in IATF 16949-certified facilities and qualified to AEC-Q101 - available through Aetrix Electronics upon request.