Allegro MicroSystems A6274KLPTR-T-1

Overview

A6274KLPTR-T-1 from Allegro MicroSystems is a latching-mode, six-channel linear LED current regulator IC for automotive rear lighting systems. It sinks up to 60 mA per channel across LED1–LED6, supports internal/external PWM dimming (200 Hz–2 kHz), features VIN derating (5–42 V), thermal foldback (–40°C to 150°C), and integrated fault detection including open-LED, short-to-ground, and overtemperature shutdown.

For engineers reviewing the A6274KLPTR-T-1 datasheet, A6274KLPTR-T-1 pinout, A6274KLPTR-T-1 application, or A6274KLPTR-T-1 equivalent, this page delivers verified technical context, validated pin functions, real-world automotive lighting use cases, and two confirmed alternative parts with documented functional differences - all grounded in Allegro's A6274-84-DS Rev. 4 specification.

Technical Context

The A6274KLPTR-T-1 implements dual-group LED control (EN1/LED1–3 and EN2/LED4–6) with independent ISET1/ISET2 current programming, enabling precise per-group brightness tuning. Its latching MODE1 operation ensures persistent fault reporting via FFn until reset by toggling VIN or ENx, critical for ASIL-B-compliant lighting diagnostics.

It integrates a gate driver for external P-MOSFET ballast regulation, reducing on-die power dissipation while supporting low-dropout operation (drives two WLEDs from 7 V). Fault detection includes VOUT short-to-ground (threshold: 1 V), LED string open (VOLED_dis = 10 V), and thermal shutdown at 175°C with 30°C hysteresis.

Key Specifications

Pinout & Package

20-pin eTSSOP (LP) package with exposed thermal pad, optimized for high-power automotive LED driver thermal performance on 4-layer PCBs (R_θJA = 29°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with A6284KLPTR-T-1, the A6274KLPTR-T-1 offers lower thermal stress and simpler biasing for moderate-current arrays; versus ASL3416SHN, it delivers autonomous analog dimming and reduced firmware overhead at the cost of configurability.

Availability

A6274KLPTR-T-1 is available at Aetrix Electronics and suitable for automotive rear combination lights, DRL/position lamps, and stop lamp modules requiring stable component supply across extended temperature ranges and stringent AEC-Q100 compliance.

Supply support for A6274KLPTR-T-1 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 power ICs and magnetic sensors, specializing in automotive-grade motion control and energy-efficient power management solutions.

The A6274 product line delivers latching and non-latching linear LED drivers optimized for ASIL-B-compliant exterior lighting, emphasizing fault resilience, wide-input operation, and thermal robustness in engine bay and lamp housing environments.

FAQ

What is the key functional difference between A6274KLPTR-T-1 and A6274KLPTR-T?

The A6274KLPTR-T-1 implements latched MODE1 fault response, holding the FFn pin low until VIN or ENx is cycled after any fault (open-LED, short, overtemperature). In contrast, A6274KLPTR-T uses unlatched MODE0, where FFn returns high automatically once the fault condition clears. This makes A6274KLPTR-T-1 suitable for safety-critical automotive diagnostics requiring persistent fault indication. Both share identical electrical specs and pinout.

How does the A6274KLPTR-T-1 achieve thermal protection without external components?

The A6274KLPTR-T-1 integrates a junction temperature sensor that begins linearly reducing LED current at 130°C (TJM), reaching 0% at 175°C (TJF). It then shuts down completely and asserts FFn low. Recovery occurs at 145°C due to 30°C hysteresis. No external thermistor or monitoring circuit is needed - the behavior is fully internal and production-tested across –40°C to 150°C.

Can the A6274KLPTR-T-1 drive LED strings without an external P-MOSFET?

Yes. The A6274KLPTR-T-1 operates in direct-drive mode when GATE and COMP pins are tied to VIN. In this configuration, it regulates current through internal pass transistors. However, fault detection for LED string open (Faults D–G) is disabled, and power dissipation rises significantly above 7 V input - limiting practical use to low-V_f strings or low-duty-cycle applications.

What is the minimum recommended PWM frequency for reliable dimming with A6274KLPTR-T-1?

The minimum recommended internal PWM frequency is 200 Hz, set by a 71.5 kΩ resistor from PWMIN to GND. Below this, flicker becomes perceptible to human vision. At 200 Hz, the A6274KLPTR-T-1 maintains ±2% current accuracy and supports duty cycles from 5% to 90% via DR pin voltage (0.2–3.2 V), meeting UNECE R149 photometric requirements for automotive lamps.

How does the A6274KLPTR-T-1 handle unused LED channels during startup?

During tLEDdet (5 ms), the A6274KLPTR-T-1 sources 65–95 µA (ILEDsrc) into each LEDx pin. If the resulting voltage falls within 0.18–0.34 V (VLEDx(NULL)), the channel is flagged as unused and removed from regulation and fault monitoring. Unused pins must be terminated with a pull-down resistor (e.g., 3.3 kΩ) to ground - a requirement explicitly defined in the A6274-84-DS Rev. 4 startup sequence.