Infineon TLE7250SJ LIN Transceiver: Features, Applications, and Design Considerations

The Infineon TLE7250SJ is a highly integrated Local Interconnect Network (LIN) transceiver designed to serve as the robust physical layer interface between a LIN master/slave protocol controller and the LIN bus itself. As a key component in modern vehicle networking, it enables reliable, low-cost communication for sensors and actuators in sub-networks. Complying with the LIN 2.x, SAE J2602, and ISO 17987-4 standards, it is engineered to meet the stringent requirements of the automotive environment.

Key Features and Technical Advantages

The TLE7250SJ stands out due to its comprehensive feature set tailored for automotive resilience and functionality. A primary feature is its very low power consumption in sleep mode, typically drawing just 5 µA, which is critical for battery-powered applications. It supports high-speed data transmission up to 20 kbaud, ensuring timely and accurate communication across the network.

Its robust ESD protection, rated up to 6 kV according to the Human Body Model (HBM) on the LIN pin, safeguards the IC and the wider system from electrostatic discharge events common during manufacturing and handling. Furthermore, the device offers excellent electromagnetic compatibility (EMC) performance and is highly resistant to electromagnetic interference (EMI), which is paramount in the electrically noisy environment of an automobile.

The transceiver incorporates multiple protection mechanisms, including over-temperature shutdown and bus terminal protection against short circuits to battery and ground. The integrated waveform shaping feature minimizes electromagnetic emissions by controlling the slew rate of the output signal, thereby reducing the potential for the LIN bus to act as an antenna.

Primary Applications in Automotive Electronics

The TLE7250SJ finds its home in a wide array of in-vehicle applications where a simple, cost-effective, and reliable communication link is required. Typical use cases include:

Body Control Modules: For controlling windows, mirrors, seats, and interior lighting.

Comfort and Convenience Systems: Such as sunroofs, climate control fans, and wiper control.

Sensor Clusters: Transmitting data from simple sensors like seat occupancy sensors or rain/light sensors.

Door and Seat Control Units: Enabling communication between electronic control units (ECUs) within a localized area.

Essential Design Considerations

Successfully implementing the TLE7250SJ requires careful attention to several design aspects:

1. Power Supply and Grounding: A stable and clean power supply is crucial. It is recommended to use a decoupling capacitor close to the VSUP pin to buffer against voltage dips and suppress noise.

2. LIN Bus Termination: Proper termination is required at both ends of the LIN bus to prevent signal reflections. The master node typically uses a 1 kΩ resistor in series with a diode and a slave node uses a 30 kΩ resistor (values as per LIN specification). A pull-up resistor on the LIN line is integrated within the master's transceiver.

3. PCB Layout: To ensure signal integrity and minimize EMI, the LIN trace should be kept as short as possible. It is good practice to route the LIN trace away from noisy switching signals or sensitive analog traces.

4. Fault Diagnosis: The device provides a dedicated INH inhibit output pin that can control an external voltage regulator. This allows the system to enter a full low-power sleep mode and can be used to manage the power domain of the associated microcontroller.

5. Thermal Management: While the IC is protected against overtemperature, ensuring adequate copper area for the exposed ground pad (DDPAK package) or pins (SOIC-8 package) helps dissipate heat during short-circuit events, enhancing long-term reliability.

ICGOODFIND Summary

The Infineon TLE7250SJ is a premier choice for automotive designers seeking a reliable, feature-rich, and AEC-Q100 qualified LIN transceiver. Its ultra-low quiescent current, superior robustness against ESD and EMI, and integrated protection features make it an ideal solution for a broad spectrum of body and comfort electronics applications, simplifying design while ensuring network reliability.

Keywords: LIN Transceiver, Automotive Networking, Low Power Consumption, ESD Protection, Electromagnetic Compatibility (EMC)