Allegro MicroSystems A6261KLPTR-T

Overview

A6261KLPTR-T from Allegro MicroSystems is a linear, programmable LED current regulator IC in 16-pin TSSOP (LP) package with exposed thermal pad, delivering up to 100 mA per channel across four matched outputs (LA1–LA4), ±4% current accuracy, and automotive-grade –40°C to 125°C operation. It drives high-brightness LED arrays in automotive lighting modules requiring precise, thermally robust constant-current control.

For engineers reviewing the A6261KLPTR-T datasheet, A6261KLPTR-T pinout, A6261KLPTR-T application, or A6261KLPTR-T equivalent, key selection criteria include its 6–50 V input range, 800 mV dropout at 100 mA, integrated short-to-ground and open-LED protection, thermal foldback via THTH pin, and PWM dimming support via EN input.

Technical Context

The A6261KLPTR-T implements four independent linear current regulators referenced to a 1.2 V internal IREF, each scaled by GH0 = 12.5× to set output current via external RREF. Current matching is ≤5% across all active channels under matched load conditions.

It integrates fault detection logic that disables all outputs on open-LED detection (VOCD = 170–450 mV, tOCD = 2 ms), asserts FF flag on short-to-ground (VSCD = 1.2–1.8 V), and enables thermal current reduction starting at TJM = 95–130°C with dISEN/dTJ = –2.5%/°C slope and full shutdown at TJF = 170°C.

Key Specifications

Pinout & Package

Package: 16-pin TSSOP (LP) with exposed thermal pad - optimized for high-power dissipation in automotive PCB layouts using thermal vias and copper pour.

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 A6261KLPTR-T delivers superior thermal simplicity in compact 16-pin TSSOP layout, lowest sleep current (10 µA), and deterministic open-LED response-making it optimal for cost-sensitive, space-constrained automotive lighting where analog reliability is prioritized over digital configurability.

Availability

A6261KLPTR-T is available at Aetrix Electronics and suitable for automotive front lighting, commercial vehicle signaling, industrial status indication, and off-highway equipment lighting requiring stable component supply and AEC-Q100 compliance.

Supply support for A6261KLPTR-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 A6261 product line is designed specifically for protected, high-reliability LED array driving in automotive exterior lighting-emphasizing fault resilience, thermal robustness, and AEC-Q100 qualification.

FAQ

What is the maximum LED string voltage supported by the A6261KLPTR-T?

The A6261KLPTR-T does not impose a fixed maximum LED string voltage. Its operational limit is determined by the dropout voltage (≤800 mV at 100 mA) and supply voltage (up to 50 V). For example, with VIN = 12 V, the maximum total forward voltage across a string is ~11.2 V-supporting up to three 3.6 V white LEDs or four 2.8 V red LEDs. Always verify thermal dissipation using RθJA = 34°C/W (4-layer PCB) to avoid exceeding TJ(max) = 150°C.

How do I calculate the RREF value needed to set 90 mA per channel on the A6261KLPTR-T?

To set 90 mA per channel on the A6261KLPTR-T, use the formula RREF = (1.2 V × GH0) / ILAx, where GH0 = 12.5 and ILAx = 90 mA. This yields RREF = (1.2 × 12.5) / 0.09 = 167 Ω. A standard 1% metal-film resistor of 165 Ω or 169 Ω is acceptable. Ensure RREF is placed close to IREF and GND pins with short traces to minimize noise coupling into the reference node.

Does the A6261KLPTR-T support parallel operation of multiple channels to increase current per string?

Yes-the A6261KLPTR-T allows LA1–LA4 outputs to be wired in parallel to sum current, e.g., connecting LA1 and LA2 increases drive capability to 200 mA for a single high-intensity LED string. However, current matching remains ≤5% only when channels operate under identical thermal conditions; localized heating degrades matching. Do not parallel outputs unless PCB layout ensures uniform thermal coupling and voltage drop across both paths.

What happens to the A6261KLPTR-T when a single LED opens in one string?

When a single LED opens in any string driven by the A6261KLPTR-T, the voltage across that LAx output rises above VOCD (170–450 mV), triggering open-load detection after 2 ms. All four outputs are immediately disabled, and the FF pin goes high (open-drain, requires pull-up). The fault persists until EN is cycled low-high, power is reset, or FF is actively pulled low-enabling fail-safe behavior required in automotive lighting systems.

Can the thermal foldback threshold of the A6261KLPTR-T be adjusted, and how?

Yes-the thermal foldback activation temperature (TJM = 95–130°C) of the A6261KLPTR-T is adjustable via the THTH pin. Connecting a resistor between THTH and GND lowers VTHTH and raises TJM; connecting to a >1 V supply (e.g., 3 V or 5 V) raises VTHTH and lowers TJM. Figure 3a in the datasheet maps VTHTH (0.8–1.25 V) to TJM; Figure 3b provides recommended RTH values (e.g., 100 kΩ pull-up to 3 V for TJM ≈ 90°C). Leaving THTH open sets TJM to typical 115°C.