Allegro MicroSystems A6284KLPTR-T

Overview

A6284KLPTR-T from Allegro MicroSystems is a programmable linear current regulator IC for automotive LED array driving, featuring six 120 mA per-channel current sinks, internal/external PWM dimming control, and integrated fault protection including open-LED, short-to-ground, and thermal shutdown. It operates across 5–42 V input and supports AEC-Q100 qualified automotive lighting systems such as rear combination lamps and DRLs.

For engineers reviewing the A6284KLPTR-T datasheet, A6284KLPTR-T pinout, A6284KLPTR-T application, or A6284KLPTR-T equivalent, this page delivers verified technical context on current regulation accuracy (±2%), channel matching (0.8% typ), thermal derating behavior, fault flag signaling (FFn), and external PMOS gate drive capability - all critical for robust LED driver design in start-stop and load-dump environments.

Technical Context

The A6284KLPTR-T implements six independent, matched current sinks with ISET1/ISET2 resistor-programmable output (up to 120 mA/channel), dual enable inputs (EN1/EN2), and a dedicated DR pin for analog PWM duty cycle control (0–3.6 V). Its architecture integrates an internal bias regulator (BIAS pin, 5 V ±2.5%), VIN derating logic via VTH, and full thermal foldback down to 35% current at TJ = TJF – 7°C.

It supports both internal PWM generation (resistor-set frequency: 195–2050 Hz) and external PWM mode (logic-level compatible, <1 µs transition delay), with controlled slew-rate drivers to reduce EMI. Fault detection includes MOSFET drain short (VOUT < 1 V), LED string open (VOLED_dis = 5 × VVTH), and latched/unlatched fault reporting via active-low FFn pin.

Key Specifications

Pinout & Package

20-pin eTSSOP (LP) package with exposed thermal pad, optimized for high-power dissipation in automotive PCB layouts. Thermal pad must be soldered to ground plane for effective heat transfer.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED current regulation applications.

Compared with AL8862Q-7 and TPS92692QPWPRQ1, the A6284KLPTR-T offers superior analog dimming flexibility (internal/external PWM + FULL mode), tighter thermal response (175°C shutdown with 30°C hysteresis), and simpler layout (no inductor or external clock), making it optimal for cost-sensitive, high-reliability automotive lighting where EMI and fault resilience are prioritized.

Availability

A6284KLPTR-T is available at Aetrix Electronics and suitable for automotive rear lighting, DRL/position lamp systems, and commercial vehicle marker lights requiring stable component supply across extended temperature and voltage ranges.

Supply support for A6284KLPTR-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 magnetic sensing, power ICs, and motor driver solutions for automotive and industrial markets.

The A6284KLPTR-T belongs to Allegro's automotive LED driver product line, designed specifically for robust, fault-tolerant current regulation in exterior lighting systems operating under harsh electrical and thermal conditions.

FAQ

What is the maximum continuous LED current per channel supported by the A6284KLPTR-T?

The A6284KLPTR-T supports up to 120 mA per channel continuously under rated conditions (TJ ≤ 150°C, VIN = 14 V). This rating is validated across the full automotive temperature range (–40°C to +150°C) and includes built-in thermal derating that reduces current above TJ = 129°C to prevent overheating. The A6284KLPTR-T achieves this with matched current sinks and internal foldback logic, ensuring safe operation even in high-ambient environments like headlamp housings.

How does the A6284KLPTR-T handle input voltage transients such as load dump?

The A6284KLPTR-T withstands load-dump transients up to 42 V continuously, with absolute maximum rating of 45 V on VIN and LED pins. Its internal VIN derating circuit - configured via the VTH pin - begins reducing LED current at VINth(L) (typically 20 V) and drops to 50% at VINth(H), preventing thermal runaway during sustained overvoltage. Unlike basic regulators, this feature is programmable and works in tandem with thermal foldback, making the A6284KLPTR-T suitable for 24 V commercial vehicle systems where transients exceed 35 V.

Can the A6284KLPTR-T drive LED strings without an external PMOS transistor?

Yes, the A6284KLPTR-T can operate without an external PMOS transistor by connecting both GATE and COMP pins directly to VIN. In this configuration, the IC drives LEDs directly through its internal current sinks, supporting up to two series white LEDs from a 7 V input. However, omitting the PMOS eliminates drain-short fault detection (FAULT A) and increases IC power dissipation - limiting practical use to lower-current or lower-VIN applications. The A6284KLPTR-T's architecture explicitly supports both modes, with clear guidance in the datasheet for each.

What fault conditions does the A6284KLPTR-T detect and how is fault reporting implemented?

The A6284KLPTR-T detects seven distinct fault conditions: MOSFET drain short (VOUT < 1 V), single LED short, LED string short, mid-string short-to-ground, open-LED, VIN overvoltage (>43 V), and thermal overload (>175°C). All faults assert the open-drain FFn pin low. For the A6284KLPTR-T (unlatched MODE0), FFn returns high after fault removal; latching behavior requires the -1 variant. Fault details - including blanking times and recovery logic - are fully documented in Table 2 of the datasheet.

How is PWM dimming implemented on the A6284KLPTR-T and what are the key timing constraints?

The A6284KLPTR-T supports both internal PWM (resistor-programmed frequency: 195–2050 Hz) and external PWM (logic-level compatible, 200 Hz–2 kHz recommended). Internal PWM uses the PWMIN pin resistor and DR pin voltage to set frequency and duty cycle (DPWM = 139 × VDR ÷ VBIAS). Critical timing constraints include 20 ms external-to-internal mode delay and minimum 20 µs on-time to maintain current accuracy. The A6284KLPTR-T avoids LED flicker by holding outputs steady during mode transitions - no blinking occurs during PWM source switching.