Texas Instruments TL4242TDRJRQ1

Overview

TL4242TDRJRQ1 from Texas Instruments is an AEC-Q100 Grade 2 qualified automotive LED driver IC, functioning as an adjustable high-side constant-current source delivering up to 500 mA (±5%) with 4.5–42 V input range, 177 mV reference voltage, and integrated open-load/overtemperature/reverse-polarity protection for rear lighting and DRL systems.

For engineers reviewing the TL4242TDRJRQ1 datasheet, TL4242TDRJRQ1 pinout, TL4242TDRJRQ1 application, or TL4242TDRJRQ1 equivalent, key selection criteria include its WSON-8 package thermal performance (R_θJB = 15.5°C/W), PWM-enabled brightness control with <40 μs switching delay, status output with configurable fault delay, and ±5% current accuracy over –40°C to 105°C ambient.

Technical Context

The TL4242TDRJRQ1 implements a precision bandgap-referenced current regulation loop that maintains 177 mV (typ) across an external shunt resistor (R_REF = 0.39–10 Ω) to set output current. Its high-impedance PWM input enables direct MCU interface without level-shifting and supports sleep mode (<1 μA I_qOFF) when pulled low.

Protection architecture includes open-load detection via ST pin voltage threshold (15–25 mV low-level trip), thermal shutdown at 150°C junction temperature, and reverse-polarity tolerance up to –42 V. The status output is open-collector with ≥4.7 kΩ pullup requirement and programmable reaction delay via capacitor on D pin.

Key Specifications

Pinout & Package

TL4242TDRJRQ1 uses the DRJ (WSON-8) package: 4.00 mm × 4.00 mm body with exposed thermal pad soldered to PCB ground plane for optimal heat dissipation (R_θJB = 15.5°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS92692QPWPRQ1 and LM3409QMYX/NOPB, TL4242TDRJRQ1 delivers simpler layout, integrated diagnostics, and guaranteed AEC-Q100 compliance in a thermally optimized WSON-8 package-ideal for space-constrained automotive rear lighting modules requiring zero-additional-fault-sensing components.

Availability

TL4242TDRJRQ1 is available at Aetrix Electronics and suitable for automotive rear lighting, daytime running light (DRL), fog light, position light, and interior ambient lighting applications requiring stable component supply across extended temperature ranges and rigorous automotive qualification.

Supply support for TL4242TDRJRQ1 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 company designing analog ICs, embedded processors, and digital signal solutions for industrial, automotive, and consumer markets.

The TL4242-Q1 product line delivers AEC-Q100-qualified LED drivers optimized for automotive exterior lighting systems, emphasizing robustness against reverse polarity, load dumps, and thermal stress in engine bay and exterior lamp housings.

FAQ

What is the maximum output current accuracy specification for TL4242TDRJRQ1?

The TL4242TDRJRQ1 guarantees ±5% output current accuracy over temperature and input voltage variations. This is achieved through tight regulation of the 177 mV (typ) reference voltage across the external R_REF shunt resistor. At 376 mA nominal output (R_REF = 0.47 Ω), the actual current remains within 357–395 mA across –40°C to 105°C ambient, as confirmed in the Electrical Characteristics table of the SLVS732G datasheet.

How does the TL4242TDRJRQ1 implement open-load detection?

The TL4242TDRJRQ1 detects open-load conditions by monitoring the voltage at the REF pin. During normal operation, REF is regulated at 177 mV. If the LED string opens, current ceases, causing REF voltage to fall below 25 mV (typical lower threshold). This triggers the ST pin to go low after a programmable delay set by the capacitor on the D pin. The TL4242TDRJRQ1 thus provides hardware-level fault reporting without MCU intervention.

Can TL4242TDRJRQ1 operate with input voltages below 4.5 V?

No, TL4242TDRJRQ1 is not specified for operation below 4.5 V input. The Recommended Operating Conditions table explicitly defines 4.5 V as the minimum supply voltage. Below this threshold, the internal bandgap reference and regulation loop cannot maintain stable 177 mV REF voltage, resulting in unpredictable current output and potential failure to enable the Q output. For sub-4.5 V applications, alternative drivers such as the TLC5940 or TPS6106x series should be evaluated.

What thermal design considerations apply to TL4242TDRJRQ1 in WSON-8 (DRJ) package?

For TL4242TDRJRQ1 in DRJ package, thermal vias under the exposed pad and maximum copper pour on inner layers are essential to achieve R_θJB = 15.5°C/W. Layout guidelines require ≥85% solder coverage on the thermal pad and plated-shut vias to prevent voids. With 300 mA output and 13.5 V input, power dissipation reaches ~2.5 W; without adequate copper area, junction temperature exceeds 150°C shutdown threshold even at 25°C ambient.

Is TL4242TDRJRQ1 pin-compatible with other packages in the TL4242-Q1 family?

No, TL4242TDRJRQ1 (WSON-8) is not pin-compatible with TL4242QKTTRQ1 (TO-263-7). Pin counts differ (8 vs. 7), pin assignments vary (e.g., NC pin exists only in DRJ), and thermal pad configurations are incompatible. Migration requires PCB redesign. However, both share identical electrical behavior, functional pin definitions (except NC), and software interface-enabling reuse of firmware and schematic logic blocks when transitioning between packages.