Allegro MicroSystems A6279ELW-T

Overview

A6279ELW-T from Allegro MicroSystems is a 16-channel serial-input constant-current latched LED driver with open-LED detection, designed for high-reliability LED display systems. It features 3.0–5.5 V logic supply operation, up to 90 mA per output sink current (set via external R_EXT), 20 ns output staggering delay, and integrated UVLO/thermal shutdown. Used in industrial signage and automotive dashboard displays where fault-aware LED driving is critical.

For engineers reviewing the A6279ELW-T datasheet, A6279ELW-T pinout, A6279ELW-T application, or A6279ELW-T equivalent, this page delivers verified technical context, package-specific pin functions, real-world application mappings, and validated alternative options - all grounded in Allegro's official documentation and electrical specifications.

Technical Context

The A6279ELW-T integrates a CMOS shift register, parallel latches, and 16 NPN constant-current sink drivers in a single SOICW-24 package. Its Schmitt-trigger inputs enable robust noise immunity, while Power-On Reset (POR) and internal undervoltage lockout (UVLO) ensure deterministic startup behavior at V_DD ≥ 2.4 V (rising) and ≥ 2.15 V (falling).

Open-LED detection operates in dedicated Test mode: after initialization via OUTPUT ENABLE and LATCH ENABLE sequencing, error bits (0 = open/TSD, 1 = normal) are latched and serially shifted out via SERIAL DATA OUT. Output staggering (20 ns typical between consecutive outputs) reduces simultaneous switching noise and EMI.

Key Specifications

Pinout & Package

Package: SOICW-24 (suffix LW), lead-free with 100% matte tin plating; 15.40 mm × 7.50 mm footprint, 2.65 mm max height, exposed thermal pad not present (unlike LP/ET variants).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC59284DBQR and MAX7219CWG+, the A6279ELW-T uniquely combines 90 mA per-channel drive, open-LED diagnostics with serial readback, and SOICW-24 compatibility - making it the only option supporting high-current, fault-aware, static LED arrays without added sensing components.

Availability

A6279ELW-T is available at Aetrix Electronics and suitable for industrial LED signage, automotive dashboard displays, medical equipment status panels, and point-of-sale terminal indicators requiring stable component supply and long-term manufacturability support.

Supply support for A6279ELW-T 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

Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance magnetic sensors and power ICs, headquartered in Worcester, Massachusetts.

The A6279 product line targets LED display systems demanding integrated current regulation, diagnostic capability, and robust operation across industrial and automotive temperature ranges - emphasizing reliability over basic functionality.

FAQ

What is the maximum output current per channel for the A6279ELW-T?

The A6279ELW-T supports up to 90 mA per output channel, set by an external resistor (R_EXT). At R_EXT = 225 Ω and V_CE = 0.7 V, typical current is 75.5 mA. The device maintains tight matching (±6.0%) between outputs under identical conditions. This current level is confirmed in Allegro's operating characteristics table and applies specifically to the A6279ELW-T in SOICW-24 package.

Does the A6279ELW-T support open-LED detection, and how is it implemented?

Yes, the A6279ELW-T implements open-LED detection (OCD) in a dedicated Test mode. After entering OCD mode via specific OUTPUT ENABLE and LATCH ENABLE sequencing, the device compares each output's V_CE to a 0.30 V threshold. Error bits (0 = open/TSD, 1 = normal) are latched and readable via SERIAL DATA OUT. This feature is fully documented in the functional description and timing diagrams of the A6279ELW-T datasheet.

What package type is used for the A6279ELW-T, and does it include an exposed thermal pad?

The A6279ELW-T uses the SOICW-24 package (suffix LW), with dimensions 15.40 mm × 7.50 mm and maximum height 2.65 mm. Unlike the LP (TSSOP) or ET (QFN) variants, the LW package does not include an exposed thermal pad. Thermal performance relies on standard SOIC copper land patterns and PCB vias - R_θJA is 44 °C/W for the 24-pin LW variant per Allegro's thermal characteristics table.

Can the A6279ELW-T operate with a 3.3 V logic supply, and what is its input hysteresis?

Yes, the A6279ELW-T operates across a 3.0–5.5 V logic supply range, fully supporting 3.3 V microcontroller interfaces. All digital inputs (CLOCK, LATCH ENABLE, OUTPUT ENABLE) feature Schmitt-trigger action with 200–400 mV hysteresis, ensuring noise immunity in electrically noisy environments. This specification is explicitly listed in the "ELECTRICAL CHARACTERISTICS" table under "Logic Input Voltage Hysteresis" for the A6279ELW-T.

How does the A6279ELW-T handle thermal overload, and does it retain latch data during shutdown?

The A6279ELW-T triggers thermal shutdown at 165 °C (typical junction temperature), disabling outputs until temperature falls below 150 °C (15 °C hysteresis). Crucially, the shift registers and output latches remain powered and retain their stored data during thermal shutdown - no host MCU reinitialization is needed upon recovery. This behavior is confirmed in the "Thermal Shutdown" section of the A6279ELW-T functional description.