TLIN1029A-Q1: GND fluctuation

Shotaro-san,

The LIN standard allows for GND shift up to 11.5% of VBAT (see ISO 17987-4 params 22-24). If the GND shift in your test is within this specification, then it should be acceptable. Outside of this range, you risk shifting the voltage references significantly enough to cause issues with the LIN duty cycle.

Keep in mind that this is part of the international standard for LIN, so these comments apply to all LIN transceivers across manufacturers.

If you are not using the LIN protocol, then it's certainly possible to communicate using a custom protocol that accounts for these timing differences. The transceiver will still interpret LIN signals as HIGH and LOW per the electrical characteristics in the data sheet.

Best,

Danny