Diodes Incorporated AL5809-20P1-7

Overview

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

For engineers reviewing the AL5809-20P1-7 datasheet, AL5809-20P1-7 pinout, AL5809-20P1-7 application, or AL5809-20P1-7 equivalent, key selection criteria include its fixed 20mA output, 60V floating-voltage rating between IN/OUT, thermal shutdown at +165°C, PowerDI123 thermal performance (θJA = 148.6°C/W on FR-4), and compatibility with PWM dimming via external MOSFET.

Technical Context

The AL5809-20P1-7 integrates an internal low-dropout regulator powering a precision current mirror with factory-trimmed reference resistor, enabling fixed 20mA output without external components. Its floating ground architecture allows bidirectional placement-IN connected to LED cathode (low-side) or OUT connected to LED anode (high-side).

It features built-in thermal shutdown with +165°C trip point and +30°C hysteresis, operates down to 2.5V startup voltage, and maintains ±1% line regulation across 2.5V–60V V_IN-OUT, supporting long LED strings in 12V–60V systems while dissipating up to 1.24W in optimized PCB layouts.

Key Specifications

Pinout & Package

AL5809-20P1-7 uses the PowerDI123 surface-mount package (3.7mm × 2.8mm × 1.78mm), featuring exposed cathode pad for enhanced thermal conduction to PCB copper. The two-terminal design eliminates polarity concerns: both pins are functional and interchangeable based on circuit topology.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL5809-20S1-7, the -20P1-7 offers 3.5× higher power handling and integrated thermal protection; versus NSI45020AZT1G, it adds robust 60V rating and fail-safe shutdown - making it superior for industrial-grade, thermally variable LED loads.

Availability

AL5809-20P1-7 is available at Aetrix Electronics and suitable for offline LED lamps, white goods illumination, and LED signage requiring stable component supply, long-life reliability, and RoHS-compliant manufacturing.

Supply support for AL5809-20P1-7 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 semiconductor company specializing in discrete, analog, and mixed-signal ICs, with emphasis on power management, signal integrity, and LED solutions.

The AL5809 product line delivers two-terminal constant-current drivers for cost-sensitive, thermally demanding LED lighting applications - designed to replace resistive or complex switching solutions in AC/DC and DC/DC LED systems.

FAQ

What is the minimum input voltage required for AL5809-20P1-7 to regulate properly?

The AL5809-20P1-7 requires a minimum 2.5V differential between its IN and OUT terminals to initiate regulation and maintain 20mA output. Below this threshold, current drops nonlinearly; at exactly 2.5V, typical output is ≥19mA per datasheet Figure 15. This enables operation with short LED strings (e.g., two 3.2V LEDs at 6.4V total) from 12V supplies while retaining 5.6V headroom.

Can AL5809-20P1-7 be used in parallel to increase total LED current?

Yes - multiple AL5809-20P1-7 units can be paralleled to scale current (e.g., two devices yield ~40mA). Datasheet Figure 3 confirms this topology for both high-side and low-side configurations. However, ensure matched PCB thermal paths and identical trace lengths to minimize current imbalance; mismatched heating causes up to ±10% unit-to-unit deviation under load.

Does AL5809-20P1-7 require a heatsink for 20mA operation at 60°C ambient?

No external heatsink is required for 20mA operation at 60°C ambient when mounted on a standard 2-layer FR-4 PCB with recommended 10mm × 10mm copper pad and thermal vias. At 20mA and 30V V_IN-OUT, power dissipation is 600mW; with θJA = 148.6°C/W, junction rise is ~89°C - well below the +125°C limit. Derating begins above 85°C ambient.

How does the thermal shutdown behavior affect LED operation during transient overloads?

When junction temperature reaches +165°C, AL5809-20P1-7 shuts off current completely and remains latched off until temperature falls by ≥30°C (to ≤+135°C), then resumes regulation automatically. This prevents thermal runaway during momentary overvoltage or poor heatsinking, but causes visible LED flicker if triggered repeatedly - indicating inadequate thermal design that must be corrected.