Allegro MicroSystems A8512EETTR-T

Overview

A8512EETTR-T from Allegro MicroSystems is a discontinued multi-output WLED/RGB backlight driver IC for LCD monitors and televisions, integrating a programmable-frequency boost controller and six matched internal current sinks. It operates from 8–24 V input, delivers up to 130 mA per channel via external R_ISET, supports PWM dimming at 100 Hz–5 kHz with 500:1 ratio, and enables parallel master/slave configurations for up to 36 LED strings.

For engineers reviewing the A8512EETTR-T datasheet, A8512EETTR-T pinout, A8512EETTR-T application, or A8512EETTR-T equivalent, this page provides verified technical context, thermal performance data (R_θJA = 32 °C/W), real-world fault protection behavior (OVP, short/open LED detect, TSD), and validated alternative part guidance for legacy design support and BOM continuity planning.

Technical Context

The A8512EETTR-T implements fixed-frequency current-mode boost control with externally adjustable switching frequency (300 kHz–1 MHz via R_FSET) and integrated gate driver delivering 7 V regulated output for standard N-channel MOSFETs. Its six current sinks feature ±0.6% matching accuracy and active current sharing across LED strings.

It employs dual-level cycle-by-cycle current limiting for soft-start and overload protection, combined with independent open/short LED detection per channel, adjustable overvoltage protection (19.5–21.0 V threshold), and thermal shutdown at 165 °C. The device supports three startup modes: EN-triggered, PWM-triggered, or battery-ramp initiated.

Key Specifications

Pinout & Package

The A8512EETTR-T is housed in a 28-contact 5 mm × 5 mm QFN package (ET) with exposed thermal pad soldered to PCB ground plane for enhanced thermal dissipation. All pins are lead-free with 100% matte tin plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ3367-AEC1 and LM3409QMHX/NOPB, the A8512EETTR-T uniquely combines integrated current sinks, master/slave scalability, and comprehensive fault protection in a single QFN package-making it irreplaceable for existing medium-to-large LCD display platforms where thermal performance (32 °C/W) and ±0.6% matching are design-critical.

Availability

A8512EETTR-T is available at Aetrix Electronics and suitable for LCD monitor backlighting, television backlighting, industrial HMI displays, and medical imaging display systems requiring stable component supply despite end-of-life status.

Supply support for A8512EETTR-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 of high-performance magnetic sensors and power ICs, specializing in motion control, energy-efficient power conversion, and precision analog solutions.

The A8512 product line was engineered specifically for medium-size LCD display backlighting, emphasizing thermal efficiency, multi-string current matching, and robust fault resilience in cost-sensitive consumer and industrial applications.

FAQ

What is the thermal resistance (R_θJA) of the A8512EETTR-T, and how does it impact thermal design?

The A8512EETTR-T has a measured R_θJA of 32 °C/W on a 4-layer JEDEC-standard PCB. This value means that at 1.2 W of internal power dissipation, the junction temperature rises approximately 38.4 °C above ambient. To maintain TJ ≤ 150 °C in an 85 °C ambient environment, designers must ensure adequate copper area under the exposed pad and minimize trace resistance to ground. The ET package's thermal pad is mandatory for reliable operation at full current capability.

How does the A8512EETTR-T handle an open LED string during operation?

When an enabled LED string opens, the corresponding LEDx pin voltage drops to near zero. The A8512EETTR-T detects this condition and removes the open string from the boost regulation loop once overvoltage protection (OVP) is triggered-typically at ~69 V with ROVP = 249 kΩ. Remaining strings continue normal operation at full current, and the open string is automatically re-engaged if reconnected or if another OVP event occurs elsewhere. This behavior avoids full system shutdown and preserves display functionality.

Can the A8512EETTR-T be used in master/slave configurations, and what are the wiring requirements?

Yes-the A8512EETTR-T supports master/slave operation: one master IC controls the boost converter while up to five slave A8512EETTR-T units regulate only LED current. Slaves require connection of EN, PWM, AGND, LGND, and LEDx pins; the master's DRIVER, VREG7V, and VOUT drive the shared power stage. No dedicated control bus is needed-the architecture relies on synchronized enable and PWM signals across all devices.

What is the maximum LED current per channel supported by the A8512EETTR-T, and how is it set?

The A8512EETTR-T supports up to 130 mA per channel, set by connecting an external resistor R_ISET between the ISET pin and AGND. Using the formula I_SET = 1.235 V / R_ISET (kΩ), the internal gain of 640 yields I_LED = I_SET × 640. For example, R_ISET = 9.5 kΩ sets I_SET ≈ 129.5 µA, resulting in ~83 mA per channel. Full 130 mA requires R_ISET ≈ 9.5 kΩ and sufficient thermal margin.

Is the A8512EETTR-T still recommended for new designs, and what is its production status?

No-the A8512EETTR-T is officially discontinued. Allegro MicroSystems states it is "no longer in production" and "should not be purchased for new design applications." Samples are unavailable. However, Aetrix Electronics maintains limited legacy inventory and provides full technical documentation, pinout validation, and equivalent-part guidance to support ongoing manufacturing, repair, and lifecycle management for existing products using the A8512EETTR-T.