TCAN1042HG: pull-up resistor of TXD

Yang Wu

Part Number: TCAN1042HG
Other Parts Discussed in Thread: TCAN1044A-Q1

Hi Team,

In the DS of TCAN1042HG, it says TXD & STB has internally pulled up to VCC, what's the value of internal pull-up resistor? In addition, it also says an adequate external pull-up resistor may also be used to ensure that the CAN controller output of the microcontroller maintains adequate bit timing to the TXD input. How to decide the value of the external pull-up resistor?

Thanks a lot.

Best regards,

Yang

over 1 year ago

0 Danny Bacic over 1 year ago

TI__Mastermind 22635 points

Hi Yang,

For the pull-up strength, you can see this characterized in the device data sheet as I_IL, which is the low-level input leakage current. When TXD is low (~0 V), the current flow into the TXD pin is typically 25 µA (ranging between 7 µA and 100 µA worst-case).

Yang Wu said:
How to decide the value of the external pull-up resistor?

An external pull-up is not required for the device to operate. The external pull-up, if applied, is based upon the characteristics of the microcontroller and the system overall. See this prior E2E question for additional information:

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/826181/tcan1042-q1-does-this-device-need-to-add-pull-up-or-pull-down-resistors-on-tx-and-rx-pin

Also, based on the application, please consider TCAN1044A-Q1 in this socket.

Best,

Danny

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TCAN1042HG: pull-up resistor of TXD