Diodes Incorporated AL8843SP-13

Overview

AL8843SP-13 from Diodes Incorporated is a hysteresis-mode DC-DC step-down LED driver IC with integrated 40V NDMOS power switch, designed for constant-current driving of single or multiple series-connected LEDs from 4.5V–40V input. It delivers up to 3A output current with ±4% accuracy, supports analog/PWM dimming via a single CTRL pin, and operates up to 1MHz switching frequency in SO-8EP package-used in low-voltage industrial lighting and LED retrofit applications.

For engineers reviewing the AL8843SP-13 datasheet, AL8843SP-13 pinout, AL8843SP-13 application, or AL8843SP-13 equivalent, key selection criteria include input voltage range (4.5–40V), output current programmability via R_SET, dual-mode dimming interface, thermal shutdown threshold (+150°C), and inherent open-circuit/short-circuit LED protection.

Technical Context

The AL8843SP-13 employs fixed-frequency hysteresis control with internal current sensing referenced to the SET pin, where V_SET = 100mV ±4% defines nominal output current (I_{OUT_NOM} = 0.1/R_SET). Its high-side current sense architecture eliminates external shunt placement constraints while enabling accurate average current regulation independent of LED forward voltage variation.

Control logic integrates soft-start (0.1ms default, adjustable via CTRL-to-GND capacitor), overtemperature protection (150°C trip, 30°C hysteresis), and multi-function CTRL pin handling on/off, analog dimming (0.4–2.5V), and PWM dimming (0.3V/2.6V thresholds). The SO-8EP package provides low θ_JA = 56°C/W via exposed pad thermal connection to PCB ground plane.

Key Specifications

Pinout & Package

AL8843SP-13 is housed in an SO-8EP (Small Outline-8 Exposed Pad) package with gull-wing leads and thermally enhanced exposed copper pad (EP) tied to GND. The package complies with RoHS, halogen-free, and lead-free requirements per Diodes Incorporated Green standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL8860Q-13 and MPQ4425AGU-AEC1-P, the AL8843SP-13 prioritizes minimal external components, intuitive single-pin dimming, and industrial-grade reliability at lower unit cost-making it ideal for high-volume, fixed-function LED lighting where automotive qualification or digital bus control is unnecessary.

Availability

AL8843SP-13 is available at Aetrix Electronics and suitable for LED retrofit for low voltage halogen, low voltage industrial lighting, and illuminated signs requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for AL8843SP-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 analog ICs, specializing in high-reliability power management, signal integrity, and lighting solutions for industrial, computing, and consumer markets.

The AL8843SP-13 belongs to Diodes' LED Driver product line, engineered specifically for cost-effective, robust constant-current regulation in non-automotive solid-state lighting applications-emphasizing ease of design-in, thermal resilience, and protection feature integration.

FAQ

What is the minimum R_SET value supported for 3A operation?

The AL8843SP-13 achieves 3A nominal output current with R_SET = 0.033Ω, yielding V_SET = 100mV per the I_{OUT_NOM} = 0.1/R_SET equation. This resistor must handle ≥100mW (I²R = 3² × 0.033), so a 0.1W or higher precision metal-film or thick-film resistor is recommended. Lower values risk exceeding internal comparator voltage limits and are not specified.

Can the AL8843SP-13 drive LEDs with total forward voltage exceeding 40V?

No-the AL8843SP-13 is a step-down (buck) converter whose maximum output voltage is limited by input voltage minus dropout. With 40V max VIN and typical 1.5V switch/diode losses, practical V_OUT is ≤38.5V. For >40V LED strings, a boost or buck-boost topology is required; this device is intended for strings where V_F < V_IN − 2V under all operating conditions.

How does the CTRL pin behave during soft-start with an external capacitor?

When a capacitor C_CTRL is connected from CTRL to GND, the soft-start time increases from the default 0.1ms to approximately (0.1ms + 1.5ms/nF × C_CTRL). The rising CTRL voltage ramps linearly, delaying turn-on until it crosses the 0.45V analog dimming threshold. This controls inrush current and stabilizes PWM dimming startup transients without requiring external timing circuitry.

Is the SO-8EP exposed pad electrically isolated or internally grounded?

The exposed pad (EP) of the AL8843SP-13 SO-8EP package is internally connected to GND-not isolated. It must be soldered to a PCB copper pour tied directly to the main GND net to ensure proper thermal conduction (θ_JA = 56°C/W) and low-impedance grounding. Leaving it floating or connecting it to a different net violates thermal and electrical specifications and risks malfunction or damage.