TLIN1029-Q1: external components selection

Dongbao,

Thank you for bringing these questions to our attention, I am happy to help.

1. R6 is used to limit the current into the pin, so a 10k resistor will work. C1 is to shunt any high frequency noise and to slow down the edges a small amount to help with emissions, and 15pF is a good value for this. Going up to 50-100pF is okay too, but when you start getting higher you will slow down the rising edges too much and cause communication problems. For R2, how will the EN pin be used? Connected to a microcontroller? R2 isn't completely necessary, though it is recommended, and will be dependent on the R3 value.

2. This isn't necessary, unless there is worry about the current limit of the device attached to RXD. This is a low-current, low-voltage output, so it shouldn't cause problems and need the current to be limited.

3. The value of C3 is dependent on the R8 value. For a 1k pull-up resistor at R8, the value for C3 is 220pF, and this is specified in the LIN standard. 1nF is only used for certain parameter testing of the LIN pin, and isn't used in applications.

4. 100nF is good for high frequency decoupling, but because VSUP is connected to the battery, it's good to have high "bulk" capacitance on the line as well. This helps with lower frequency noise, but also keeps the voltage seen by the VSUP pin at a suitable level for operation in case another part of the application (another ECU in the vehicle) pulls a large amount of current from the battery and causes the voltage level to dip. 1uF and 10uF help in these cases, and are therefore recommended along with the 100nF.

5. Master and slave mode identify how the communication scheme will be set up in each LIN cluster. The Master device controls the LIN bus while all the Slave devices respond to the Master's requests and messages. The Master node needs an external pull-up and diode to be able to deliver more current to multiple devices on the LIN bus, thus it has a stronger pull-up (lower resistance equals higher current). The diode is to help protect from any reverse voltage spikes from the battery line to the LIN bus. For slave mode, the resistor and diode are integrated into the transceiver itself, which is why it is not necessary to have those external components.

Please let me know if you have any other questions or issues, and let me know if you can give me answer for my question in part 1.

Regards,