Infineon TLE7250VLE LIN Bus Transceiver: Key Features and Application Design Considerations

The Infineon TLE7250VLE is a highly integrated Local Interconnect Network (LIN) transceiver designed to interface between a LIN protocol controller and the physical bus in a wide range of automotive and industrial applications. As a cornerstone for robust in-vehicle networking, this device combines high performance with exceptional reliability. Understanding its key features and associated design considerations is paramount for engineers to develop stable and compliant systems.

Key Features

The TLE7250VLE stands out in the market due to its comprehensive feature set tailored for the harsh automotive environment.

Compliance with LIN Standards: The device is fully compliant with the latest LIN 2.2/2.2A, SAE J2602-2, and ISO 17987-4 specifications, ensuring interoperability within standardized network architectures.

Exceptional ESD and EMI Robustness: It offers high Electrostatic Discharge (ESD) protection, exceeding 8 kV (IEC 61000-4-2) on the LIN bus pin. This is complemented by excellent Electromagnetic Immunity (EMI) performance, which is critical for maintaining signal integrity in electrically noisy environments like a car's engine compartment.

Very Low Power Consumption: Featuring multiple power-saving modes, including a low-power sleep mode with a typical current consumption of just 7 µA, the TLE7250VLE is ideal for battery-powered applications where quiescent current is a critical design parameter.

Integrated Wake-Up Features: The transceiver supports wake-up via both local wake-up through the LIN bus and a dedicated wake-up input pin (INH/EN), allowing the microcontroller to be efficiently woken from sleep, thus enabling complex network power management strategies.

Advanced Diagnostic Capabilities: The device provides extensive diagnostic functions, including overtemperature shutdown, undervoltage detection, and short-circuit protection on the bus output. This allows the host microcontroller to monitor the health of the network and take corrective actions if necessary.

Slope Control for EMI Optimization: The slew rate of the LIN bus output is controlled to minimize Electromagnetic Emissions (EME), contributing to a system that is easier to pass stringent automotive EMC tests.

Application Design Considerations

Successfully integrating the TLE7250VLE into a system requires careful attention to several design aspects.

1. Power Supply and Decoupling: A stable and clean power supply is essential. It is crucial to use a low-ESR ceramic capacitor (typically 100 nF) placed as close as possible to the VSUP pin of the IC to suppress high-frequency noise. A larger bulk capacitor may be required if the supply line is long or noisy.

2. LIN Bus Interface: The LIN bus line is a single-wire connection susceptible to external disturbances. To ensure signal quality, a series resistor (typically 1 kΩ) should be placed between the TXD input and the microcontroller to dampen any potential ringing. Furthermore, a pull-up resistor (typically 30 kΩ) and a diode are integrated inside the transceiver, simplifying the external circuit design.

3. ESD and Transient Protection: While the TLE7250VLE offers robust internal ESD protection, additional external protection, such as a Transient Voltage Suppression (TVS) diode on the LIN bus line, is highly recommended to safeguard against higher-energy transients and load dump events, especially if the LIN cable is long and exposed.

4. PCB Layout: Proper PCB layout is critical for EMC performance. The ground path for the bypass capacitor must be short and direct to the device's ground pin. The LIN trace should be kept away from noisy or high-speed signals to prevent crosstalk. A ground plane is strongly advised to provide a stable reference and shielding.

5. Thermal Management: Although the device features overtemperature protection, ensuring adequate PCB copper area for the exposed ground pad (EP) is necessary for efficient heat dissipation, especially under high ambient temperatures or during prolonged fault conditions like a bus short-circuit.

ICGOOODFIND

The Infineon TLE7250VLE LIN transceiver is a robust and highly integrated solution that simplifies the design of reliable LIN network nodes. Its combination of low power consumption, superior robustness, and comprehensive diagnostics makes it an excellent choice for a vast array of automotive body and comfort applications. By adhering to key design considerations regarding power integrity, bus interfacing, and PCB layout, engineers can fully leverage its capabilities to create systems that meet stringent automotive quality and reliability standards.

Keywords: LIN Transceiver, Automotive Networking, ESD Protection, Low Power Consumption, EMI/EMC