NXP TJA1021T/20/C,118 LIN 1 Transceiver: Datasheet, Application Circuit, and Key Features

The NXP TJA1021T/20/C,118 is a dedicated Local Interconnect Network (LIN) transceiver, serving as the physical layer interface between a LIN master/slave protocol controller and the LIN bus itself. This highly integrated chip is designed to handle all the requirements of the LIN 2.x, LIN 1.3, and SAE J2602 specifications, making it a cornerstone component in modern automotive networking for sub-systems like sensors, actuators, and smart switches.

Key Features

The TJA1021T/20/C,118 boasts a set of features optimized for the harsh automotive environment and for minimizing system cost and complexity.

Compliance and Speed: It is fully compliant with the latest LIN standards and supports a maximum transmission rate of 20 kbps.

Low Power Management: A major highlight is its very low current consumption in sleep mode, typically just 10 µA. This is critical for automotive applications where minimizing quiescent current is essential for battery life. It can be woken up either by a local wake-up signal via the LIN protocol controller or by a remote wake-up request via the LIN bus.

Robust ESD Protection: The device offers high Electrostatic Discharge (ESD) protection on the LIN bus pin, safeguarding it against transient events common in automotive environments. It meets the stringent IEC 61000-4-2 standard.

Integrated Termination: The transceiver features an internal pull-up resistor with current source for the LIN bus, simplifying the external component count. The slave node application circuit often requires only a few external passive components.

Thermal Protection: Built-in overtemperature protection shuts down the output driver if the junction temperature exceeds a safe limit, enhancing the reliability of the system.

EMC Performance: Excellent Electromagnetic Compatibility (EMC) characteristics ensure minimal emissions and high immunity to interference, preventing disruptions to other electronic systems in the vehicle.

Application Circuit

The application circuit for the TJA1021T/20/C,118 as a LIN slave node is notably simple. The core connection involves just a few pins:

Vbat (Pin 8): Connected to the vehicle's battery voltage (typically 12V) through a series resistor and a reverse polarity protection diode.

LIN (Pin 1): Connects directly to the LIN bus line. A series resistor and a capacitor to ground are often used for further EMC optimization.

TXD (Pin 5): Input from the protocol controller's transmit data line.

RXD (Pin 6): Output to the protocol controller's receive data line.

NSLP (Pin 4): The control pin that enables the transceiver from its ultra-low-power Sleep mode into Normal operating mode.

A common application includes a simple voltage regulator to provide a 5V or 3.3V supply for the accompanying microcontroller.

Datasheet Essentials

The datasheet is the ultimate source for successful implementation. Key parameters to consult include:

Absolute Maximum Ratings: Ensuring voltages (e.g., on Vbat) and temperatures stay within safe operating areas.

DC Characteristics: Details on supply current in all modes (Normal, Sleep), input voltage levels, and bus recessive/dominant states.

Waveform Characteristics: Timing diagrams for propagation delays, slew rates, and wake-up pulses.

Application Information: Detailed layouts and circuit examples provided by NXP are crucial for passing EMC tests.

ICGOODFIND Summary

The NXP TJA1021T/20/C,118 is an industry-standard LIN transceiver that delivers robust performance, ultra-low quiescent current, and high integration. Its simplicity, reliability, and compliance with automotive standards make it an optimal choice for a vast array of in-vehicle network applications, reducing design time and ensuring system integrity.

Keywords

LIN Transceiver

Low Power Consumption

Automotive Networking

NXP Semiconductors

ECU