Allegro MicroSystems A8512ELBTR-T

Overview

A8512ELBTR-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 current sinks. It operates from 8–24 V input, delivers up to 130 mA per channel via external R_ISET, supports 300 kHz–1 MHz switching, and enables parallel master/slave operation for up to 36 LED strings.

For engineers reviewing the A8512ELBTR-T datasheet, A8512ELBTR-T pinout, A8512ELBTR-T application, or A8512ELBTR-T equivalent, key selection criteria include its 24-pin SOICW (LB) package with fused pins for thermal dissipation, 500:1 PWM dimming ratio, ±0.6% LED current matching, OVP/OTP/short-open protection, and compatibility with external N-channel MOSFETs in medium-size display backlight systems.

Technical Context

The A8512ELBTR-T implements fixed-frequency current-mode boost control with integrated gate driver (7 V regulated), enabling wide MOSFET selection beyond logic-level devices. Its dual-level cycle-by-cycle current limit provides soft-start and overload protection independent of duty cycle.

Six high-accuracy current sinks operate with active sharing (±0.6% matching) and support channel disable via ground tie. Parallel operation uses a single master boost stage with up to five slave-only controllers, synchronizing regulation across all enabled LED strings without requiring inter-IC clock distribution.

Key Specifications

Pinout & Package

The A8512ELBTR-T is housed in a 24-pin SOICW (LB) package with internally fused pins for enhanced thermal dissipation and lead-free matte tin plating. The exposed internal fuse structure improves reliability under high-current transients and reduces thermal resistance compared to standard SOIC.

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 A8512ELBTR-T uniquely combines integrated current sinks, master/slave scalability, and ±0.6% matching in a single SOICW package-making it optimal for cost-sensitive, medium-power commercial display backlighting despite its discontinued status.

Availability

A8512ELBTR-T is available at Aetrix Electronics and suitable for LCD monitor backlighting, television backlighting, and commercial display applications requiring stable component supply and legacy design support.

Supply support for A8512ELBTR-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 sensing 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 robustness, current matching accuracy, and scalable multi-IC architecture for cost-effective large-panel illumination.

FAQ

What is the package type and thermal performance of the A8512ELBTR-T?

The A8512ELBTR-T uses a 24-pin SOICW (LB) package with internally fused pins for enhanced thermal dissipation. On a 2-layer PCB with 1-in² 2-oz copper, its thermal resistance is 51°C/W; on a 4-layer JEDEC-standard board, it drops to 35°C/W. This fused-pin construction improves reliability under high-current transients compared to standard SOIC packages, making it suitable for sustained LED drive loads in display backlight applications.

Can the A8512ELBTR-T be used in master/slave configurations, and how many devices can be connected?

Yes, the A8512ELBTR-T supports master/slave operation: one master device controls the boost converter stage while up to five slave devices act solely as LED current sinks. This configuration allows up to 36 LED strings (6 × 6) to be powered by a single boost inductor and external MOSFET. The master regulates output voltage based on all active strings, and slaves synchronize sink behavior without requiring additional clock or data lines-reducing system complexity and component count.

What is the maximum LED current per channel and how is it set on the A8512ELBTR-T?

The A8512ELBTR-T supports up to 130 mA per LED channel, set via an external resistor (RISET) connected between the ISET pin and AGND. The relationship is ILED = (1.235 V / RISET) × 640, allowing precise current programming-for example, 12.4 kΩ yields 64 mA per channel. Unused LEDx pins must be grounded to avoid startup faults, and multiple sinks (e.g., LED1+LED2) can be paralleled to double per-string current capability.

Does the A8512ELBTR-T support PWM dimming, and what is its dimming range?

Yes, the A8512ELBTR-T supports direct PWM dimming on the dedicated PWM pin with a 500:1 ratio (0.2% to 100% brightness). It accepts PWM frequencies from 100 Hz to 5 kHz and eliminates audible MLCC noise by avoiding sub-audible modulation. For optimal linearity at very low duty cycles (<100 µs), a 3–5 µs pulse-width compensation is recommended to offset propagation delay from PWM edge to 90% LED current rise.

What protection features does the A8512ELBTR-T include, and how do they function?

The A8512ELBTR-T integrates overvoltage protection (OVP), open/short LED detection, overtemperature shutdown (165°C trip), undervoltage lockout (6.5 V), and pulse-by-pulse overcurrent limiting. OVP uses an external ROVP resistor to set thresholds up to 69 V; short detection triggers latched shutdown if any LEDx pin exceeds 25 V; open-string events remove affected channels from regulation while maintaining others. All protections feed into the open-drain FAULT pin for system-level monitoring.