ZHCSH93 December 2017 TCAN4420
PRODUCTION DATA.
The TCAN4420 has internal pull ups and pull downs on critical terminals to place the device into known states if the terminal floats. See Table 5 for details on terminal bias conditions
| TERMINAL | PULL UP or PULL DOWN | COMMENT |
|---|---|---|
| TXD | Pull up | Weakly biases TXD toward recessive to prevent bus blockage or TXD DTO triggering |
| SW | Pull down | Weakly biases SW terminal towards GND to use the default (normal) polarity configuration |
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NOTE
The internal bias should not be relied upon as only termination, especially in noisy environments but should be considered a failsafe protection. Special care needs to be taken when the device is used with MCUs which implement open drain outputs. TXD is weakly internally pulled up. The TXD pull up strength and CAN bit timing require special consideration when this device is used with an open drain TXD output on the microprocessor CAN controller. An adequate external pull up resistor must be used to ensure that the TXD output of the microprocessor maintains adequate bit timing input to the CAN transceiver.