Allegro MicroSystems A6276ELWTR

Overview

A6276ELWTR from Allegro MicroSystems is a 16-bit serial-input, constant-current latched LED driver in 24-pin SOICW package, featuring 16 NPN sink drivers with user-adjustable current (up to 90 mA per channel via R_EXT), 20 MHz max serial data rate at 5 V, and active-low OUTPUT ENABLE for inter-digit blanking - used in multiplexed LED signage, industrial panel displays, and dot-matrix modules.

For engineers reviewing the A6276ELWTR datasheet, A6276ELWTR pinout, A6276ELWTR application, or A6276ELWTR equivalent, key selection criteria include output current matching (±1.5% typical), undervoltage lockout (3.4–4.0 V), thermal resistance (85 °C/W on 1-layer PCB), and cascade-capable CMOS serial data output.

Technical Context

The A6276ELWTR integrates a 16-bit CMOS shift register, parallel latches, and 16 matched NPN constant-current sink drivers - all operating from a single 4.5–5.5 V logic supply. Its latch-enable input enables synchronous serial-to-parallel conversion, while the active-low OUTPUT ENABLE provides global blanking without affecting latch state.

Current regulation is resistor-programmable via R_EXT (e.g., 250 Ω sets ~75.5 mA per output at V_CE = 0.7 V), and output leakage remains ≤5.0 μA at 15 V. Propagation delays are ≤1000 ns for CLOCK/LATCH/ENABLE-to-OUT paths, with rise/fall times of 150–600 ns.

Key Specifications

Pinout & Package

24-pin SOICW (wide-body) surface-mount package (JEDEC MS-013 AD), 15.40 mm × 7.50 mm × 2.65 mm, lead (Pb)-free with 100% matte tin plating. Exposed pad not present - thermal path relies on leads and PCB copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TB62706BF and A6275ELWTR, the A6276ELWTR delivers full 16-bit integration, built-in UVLO, and daisy-chain capability - reducing component count, improving reliability, and simplifying firmware for large LED arrays.

Availability

A6276ELWTR is available at Aetrix Electronics and suitable for LED signage, industrial HMI panels, and test equipment requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for A6276ELWTR 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 magnetic sensing, power ICs, and precision motion control solutions since 1989.

The A6276 product line was designed specifically for high-reliability, constant-current LED display driving - targeting applications demanding tight current matching, thermal resilience, and microcontroller-friendly serial interface.

FAQ

What is the maximum continuous output current per channel for the A6276ELWTR?

The A6276ELWTR supports up to 90 mA per output channel continuously over the full –40°C to +85°C ambient temperature range, provided thermal design meets R_θJA ≤ 85 °C/W on a 1-layer PCB. At 85°C ambient, derating applies - e.g., 75 mA typical with R_EXT = 250 Ω and V_CE = 0.7 V. The A6276ELWTR datasheet specifies absolute maximum IO = 90 mA, with recommended operating conditions limiting continuous use to values ensuring junction temperature stays below 150°C.

How does the R_EXT resistor set output current in the A6276ELWTR?

In the A6276ELWTR, the external resistor connected between pin 23 (REXT) and GND determines all 16 output currents simultaneously using an internal current mirror. For example, R_EXT = 250 Ω yields ~75.5 mA per output at V_CE = 0.7 V (typical), while R_EXT = 470 Ω yields ~40.0 mA. The relationship is inverse and linear - halving R_EXT approximately doubles output current. This single-resistor method ensures matched performance across all channels in the A6276ELWTR.

Does the A6276ELWTR support daisy-chaining with other LED drivers?

Yes, the A6276ELWTR supports seamless daisy-chaining via its CMOS SERIAL DATA OUT (pin 22), which outputs the shifted-out bit from the internal 16-bit register. This allows cascading multiple A6276ELWTR devices - for example, three chips drive 48 outputs using only one microcontroller SPI data line and shared CLOCK/LATCH ENABLE. No level-shifting or buffering is needed, and timing specifications guarantee reliable propagation up to 10 MHz in cascade configurations for the A6276ELWTR.

What is the purpose of the OUTPUT ENABLE pin on the A6276ELWTR?

The OUTPUT ENABLE pin (pin 21) on the A6276ELWTR is an active-low global blanking control that disables all 16 output drivers simultaneously without affecting the latch contents. When pulled high, outputs turn OFF (blanked); when low, outputs reflect their latched states. This enables precise inter-digit or inter-frame blanking in multiplexed LED displays - critical for eliminating crosstalk and achieving high contrast. The A6276ELWTR maintains latch integrity during blanking, allowing uninterrupted data loading.

Is the A6276ELWTR RoHS-compliant and lead-free?

Yes, the A6276ELWTR is fully RoHS-compliant and lead (Pb)-free, with 100% matte tin plating on the copper leadframe. This meets JEDEC J-STD-609 Category 1 requirements and supports standard Pb-free reflow profiles (peak 260°C). The SOICW package construction and termination finish are qualified for industrial and commercial applications where environmental compliance and solderability are mandatory - confirming the A6276ELWTR's suitability for modern manufacturing.