Texas Instruments TL4242QKTTRQ1

Overview

TL4242QKTTRQ1 from Texas Instruments is an AEC-Q100 Grade 1 qualified automotive LED driver IC, functioning as a protected high-side adjustable constant-current source delivering up to 500 mA (±5%) with 0.35–0.7 V dropout across 4.5–42 V input range. It integrates PWM brightness control, open-load detection, overtemperature protection, reverse-polarity proofing, and status reporting via open-collector ST pin - deployed in rear lighting, DRL, fog lights, and stop/tail light modules.

For engineers reviewing the TL4242QKTTRQ1 datasheet, TL4242QKTTRQ1 pinout, TL4242QKTTRQ1 application, or TL4242QKTTRQ1 equivalent, key selection criteria include its ±5% current accuracy at 500 mA, 177 mV reference voltage tolerance, 40 μs max PWM turn-on/off delay, 105°C ambient rating in WSON or 125°C in TO-263, and integrated fault reporting via configurable ST/D pins.

Technical Context

The TL4242QKTTRQ1 implements a precision bandgap-referenced current regulation loop where output current IQ is set by external shunt resistor RREF using IQ = VREF / RREF, with VREF tightly regulated at 177 mV (typ) across –40°C to +150°C junction temperature. Its high-impedance PWM input enables direct MCU-level enable/dimming without external level-shifting.

Protection architecture includes thermal shutdown (trip at ~150°C), open-load detection via ST pin low-threshold (15–25 mV), reverse-polarity tolerance up to –42 V, and short-circuit proofing. The ST output provides fault indication with programmable delay (via capacitor on D pin) and supports pullup ≥4.7 kΩ for automotive-compatible logic interfacing.

Key Specifications

Pinout & Package

TL4242QKTTRQ1 is packaged in TO-263 (KTT), a 7-pin DDPAK with exposed thermal pad, measuring 10.00 mm × 9.25 mm. Thermal pad must be soldered to PCB ground plane or left floating per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL8862Q-7 and MAX20050ATP/V+T, TL4242QKTTRQ1 offers superior current accuracy (±5% vs ±10%), native 4.5–42 V operation without external regulators, and simpler analog configuration - making it optimal for robust, low-complexity automotive lighting nodes.

Availability

TL4242QKTTRQ1 is available at Aetrix Electronics and suitable for automotive rear lighting, daytime running lights, and fog light systems requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for TL4242QKTTRQ1 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and automotive-grade ICs with decades of automotive qualification expertise.

The TL4242-Q1 product line delivers robust, high-accuracy LED drivers for safety-critical exterior lighting, engineered to meet stringent AEC-Q100 Grade 1/2 requirements and survive harsh automotive electrical environments.

FAQ

What is the maximum output current capability of the TL4242QKTTRQ1?

The TL4242QKTTRQ1 delivers up to 500 mA output current with ±5% accuracy across temperature and supply voltage. This is achieved by selecting an appropriate external reference resistor (RREF) according to IQ = VREF / RREF, where VREF is 177 mV (typ). At RREF = 0.39 Ω, the typical output is 454 mA; at RREF = 0.47 Ω, it is 376 mA - both within the specified 500 mA limit. The device also features a hard current limit of 600 mA for short-circuit protection.

How does the TL4242QKTTRQ1 implement open-load detection?

The TL4242QKTTRQ1 monitors the voltage at the REF pin, which is regulated to 177 mV during normal operation. If the LED string opens, the REF voltage drops below 25 mV (typical lower threshold), triggering the ST pin to go low after a user-configurable delay set by capacitor CD on pin D. For example, a 47 nF capacitor yields ~10 ms delay before fault assertion - allowing rejection of transient noise while ensuring reliable failure detection. This eliminates the need for external comparators in the TL4242QKTTRQ1 design.

Can the TL4242QKTTRQ1 operate directly from a 12 V automotive battery?

Yes, the TL4242QKTTRQ1 operates across 4.5 V to 42 V input, fully covering automotive battery conditions including cold-crank (down to 4.5 V) and load-dump transients (up to 42 V). Its reverse-polarity protection withstands –42 V, safeguarding against battery misconnection. No external pre-regulator or protection circuitry is needed - the TL4242QKTTRQ1 integrates all necessary protections, making it ideal for direct battery-connected LED lighting modules.

What package options are available for the TL4242QKTTRQ1?

The TL4242QKTTRQ1 is offered exclusively in the TO-263 (KTT) package: a 7-pin DDPAK with exposed thermal pad, measuring 10.00 mm × 9.25 mm. This package supports –40°C to +125°C ambient operation and features low thermal resistance (RθJA = 31.6°C/W, RθJB = 8.2°C/W), enabling high-power LED driving without additional heatsinks in properly designed PCB layouts. The WSON variant (TL4242TDRJRQ1) uses DRJ package but is a different orderable part.

Does the TL4242QKTTRQ1 require external components for basic operation?

Yes - minimal external components are required: a 100-nF ceramic capacitor on the I pin for input bypass, an external shunt resistor (RREF) on REF to set output current, a ≥4.7 kΩ pullup on ST for fault reporting, and optionally a capacitor on D to configure status delay. No external diodes, MOSFETs, or regulators are needed. The TL4242QKTTRQ1 integrates all regulation, protection, and PWM interface functions internally - reducing total solution size and bill-of-materials cost.