Allegro MicroSystems A6279ELP-T

Overview

A6279ELP-T from Allegro MicroSystems is a 16-channel serial-input constant-current LED sink driver with open-LED detection, designed for high-reliability LED display systems. It integrates a CMOS shift register, latched outputs, and NPN current sinks capable of up to 90 mA per channel (REXT = 225 Ω), operating from 3.0–5.5 V logic supply and supporting up to 25 MHz serial data input. Used in industrial signage and automotive dashboard displays where fault visibility and thermal robustness are critical.

For engineers reviewing the A6279ELP-T datasheet, A6279ELP-T pinout, A6279ELP-T application, or A6279ELP-T equivalent, this page delivers verified electrical parameters, TSSOP-LP package terminal mapping, open-circuit detection behavior, thermal shutdown thresholds, and validated alternative drivers for LED matrix control designs.

Technical Context

The A6279ELP-T implements a 16-bit serial-to-parallel shift register followed by edge-triggered latches and 16 independent NPN constant-current sink drivers. Its open-LED detection operates by monitoring V_CE across each output against a 0.30 V threshold during dedicated test mode, returning error bits via SERIAL DATA OUT.

Internal UVLO (2.15–2.85 V) and thermal shutdown (165 °C typical, 15 °C hysteresis) ensure safe operation under brownout or overload. Output staggering (20 ns typical between consecutive OUTx) reduces simultaneous switching noise and EMI, with cumulative delay up to 300 ns across all 16 channels.

Key Specifications

Pinout & Package

Package: 24-pin TSSOP with exposed thermal pad (LP suffix), 0.65 mm pitch, 7.80 × 4.40 mm body, 1.20 mm max height. Exposed pad (EP) must be soldered to PCB ground plane for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TB62786AFTG and MAX7219CWG+, the A6279ELP-T uniquely delivers 90 mA/channel drive, on-chip open-LED diagnostics with serial readback, and thermal/UVLO protection - making it the only option qualified for industrial-grade LED matrix systems requiring autonomous fault handling.

Availability

A6279ELP-T is available at Aetrix Electronics and suitable for industrial signage, automotive dashboard displays, medical status panels, and POS terminal indicator arrays requiring stable component supply and long-lifecycle support.

Supply support for A6279ELP-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 semiconductor company specializing in high-performance power ICs, magnetic sensors, and precision motor control solutions.

The A6279 product line was engineered specifically for LED display systems demanding integrated current regulation, fault visibility, and thermal resilience - targeting applications where reliability outweighs raw cost minimization.

FAQ

What is the maximum continuous output current per channel for the A6279ELP-T?

The A6279ELP-T supports up to 90 mA per output channel when R_EXT = 225 Ω and V_CE = 0.7 V at T_A = 25 °C. Derating applies per duty cycle and ambient temperature - at 85 °C ambient and 100% DC, max current drops to ~45 mA for the 24-pin LP package. Full derating curves are provided in Figures 11–12 of the official datasheet.

How does open-LED detection work on the A6279ELP-T?

The A6279ELP-T enters LED Open Circuit Detection (OCD) mode via a defined 5-clock sequence on OUTPUT ENABLE and LATCH ENABLE pins. During testing, it compares each output's V_CE against 0.30 V; values below indicate an open circuit and return '0' in the error bit. Results are serially shifted out via SERIAL DATA OUT after three additional clocks - all without MCU firmware changes.

Can the A6279ELP-T operate with a 3.3 V logic supply?

Yes, the A6279ELP-T operates across 3.0–5.5 V logic supply (V_DD). At 3.3 V, it maintains full functionality including 25 MHz serial data rate, Schmitt-triggered inputs, and open-LED detection. Logic high input threshold is 0.7×V_DD (2.31 V min), and hysteresis is 200–400 mV - ensuring noise margin in mixed-voltage systems.

What thermal management is required for the A6279ELP-T in a 24-pin TSSOP-LP package?

The A6279ELP-T in LP package requires soldering the exposed thermal pad (EP, Pin 25) to a minimum 100 mm² copper pour tied to internal ground planes. With 4-layer board layout per JEDEC standards, its R_θJA is 28 °C/W. At 90 mA × 16 channels and 100% duty cycle, junction temperature rise exceeds safe limits unless ambient is ≤45 °C - forced air or thermal vias are recommended above 50% DC.

Does the A6279ELP-T support daisy-chaining with other A6279 devices?

Yes, the A6279ELP-T supports seamless daisy-chaining: SERIAL DATA OUT of one device connects directly to SERIAL DATA IN of the next. The 16-bit shift register propagates data through the chain, and latching is synchronized globally via shared CLOCK and LATCH ENABLE lines - enabling expansion to 32, 48, or more LED channels with single MCU interface.