Infineon TLE7250LE LIN Transceiver: Key Features and Application Design Considerations

The Infineon TLE7250LE is a highly integrated LIN (Local Interconnect Network) transceiver designed to interface between a LIN protocol controller and the physical bus in automotive networks. As a key enabler for robust and cost-effective communication in body control modules, sensor interfaces, and other sub-network applications, understanding its core capabilities and design nuances is crucial for engineers.

Key Features

The TLE7250LE stands out in the crowded transceiver market due to several defining characteristics:

Comprehensive Compliance: The device is fully compliant with the LIN 2.2/2.1/SAE J2602 standards and the latest ISO 17987-4 specification, ensuring interoperability within standardized automotive networks.

Exceptional ESD Robustness: It offers outstanding electrostatic discharge (ESD) protection, exceeding ±8 kV according to IEC 61000-4-2 on the LIN bus pin. This high level of robustness is critical for surviving the harsh electrical environment of an automobile.

Very Low Power Consumption: Featuring multiple low-power modes managed via the LIN bus or the dedicated INH (Inhibit) pin, the TLE7250LE is optimized for energy efficiency. Its very low current consumption in sleep mode (typically just a few µA) makes it ideal for battery-connected applications where quiescent current is a primary concern.

Integrated Wake-Up Features: The transceiver supports local and remote wake-up functionality via the LIN bus or the WAKE pin. This allows the network node to be roused from sleep mode by a specific bus event or a local signal, enabling complex power management strategies.

Enhanced Electromagnetic Compatibility (EMC): The device incorporates advanced slope control and filtering to minimize electromagnetic emissions (EME) and improve susceptibility to electromagnetic interference (EMI), contributing to a quieter and more reliable electrical system.

Application Design Considerations

Successfully implementing the TLE7250LE requires careful attention to the application circuit design:

1. Bus Termination and Biasing: A proper termination network is essential for signal integrity. A series resistor (e.g., 1kΩ) is typically placed between the transmitter output (TXD) and the transceiver's TXD input to dampen reflections. The LIN bus itself requires a pull-up resistor (typically 1kΩ to 30kΩ) and a series diode at the master node, while slave nodes usually have a much higher pull-up resistor (e.g., 47kΩ) or none at all, as specified by the LIN standard.

2. Power Supply and Decoupling: A stable and clean power supply is mandatory. It is critical to use a low-ESR decoupling capacitor (e.g., 100 nF) placed as close as possible to the `VSUP` pin of the IC to suppress high-frequency noise. For additional stability, a larger bulk capacitor (e.g., 4.7 µF) may be used on the supply rail.

3. ESD and Transient Protection: While the TLE7250LE has excellent integrated ESD protection, applications in particularly demanding environments may benefit from additional external protection components, such as a Transient Voltage Suppression (TVS) diode on the LIN bus line, to clamp higher-energy transients.

4. PCB Layout: A good PCB layout is paramount for EMC performance. The LIN bus trace should be kept as short as possible and routed away from noisy signals (e.g., clock lines, switching power supplies). The ground connection must be solid, and the area of the high-current loops should be minimized.

5. Slope Control and Timing: The slew rate of the LIN output is internally controlled to manage EME. Designers must ensure that the microcontroller's baud rate and timing are correctly configured to match the transceiver's propagation delays, guaranteeing proper synchronization within the LIN frame structure.

ICGOOODFIND

The Infineon TLE7250LE LIN transceiver proves to be a robust, efficient, and highly reliable solution for modern automotive networking. Its combination of low power consumption, superior ESD protection, and full standard compliance makes it a top choice for designers building reliable slave and master nodes for LIN clusters. Careful attention to termination, supply decoupling, and PCB layout will ensure that the system fully leverages the IC's capabilities, resulting in a stable and error-free communication network.

Keywords: LIN Transceiver, Automotive Networking, Low Power Consumption, ESD Protection, ISO 17987