TLIN2021A-Q1: LIN pin voltage when Vsup is 58V

Hi Lijia,

Because this Vsup condition is technically outside of the recommended operating conditions for the device, we cannot guarantee the functional behavior in this state. However, the state of the LIN bus during this test conditions will be largely determined by the interactions of some system characteristics and and timing of the 58V Vsup condition. 

The LIN driver itself is a low-side transistor with an internal pull-up resistor which is active in Normal and Standby mode. For simplicity, we an assume the driver is inactive and only the internal pull-up resistor is impacting the voltage on the LIN bus. When Vsup is increased to 58V, the reference of this pull-up resistor also becomes 58V and the LIN bus capacitance will begin to charge through the pull-up resistor. The actual voltage reached on the LIN bus will be determined by this pull-up resistor value (45kΩ), the LIN bus capacitance, and the amount of time the 58V Vsup is applied. 

If this is a system-level consideration, then it would likely be assumed that all LIN devices on the network also have their Vsup rise to 58V. This means that this charge path through the internal pull-up resistors would all exist in parallel and the fixed LIN bus capacitance would be much faster - especially through the Master node with an external 1kΩ pull-up. Again though, the final maximum LIN voltage will depend on the amount of time that Vsup is held at 58V. 

Let me know if you have any more questions.

Regards,
Eric Schott