Pin 1 (VSUP): This is the supply pin for the device. A 100 nF decoupling capacitor should be placed as close to the device as possible.
Pin 2 (EN): EN is an input pin that is used to place the device in a low power sleep mode. If this feature is not used, the pin should be pulled high to the regulated voltage supply of the microprocessor through a series resistor, values between 1 kΩ and 10 kΩ. Additionally, a series resistor may be placed on the pin to limit current on the digital lines in the event of an over-voltage fault.
Pin 3 (GND): This is the ground connection for the device. This pin should be tied to the ground plane through a short trace with the use of two vias to limit total return inductance.
Pin 4 (LIN): This pin connects to the LIN bus. For responder node applications, a 220 pF capacitor to ground is implemented. For commander node applications, an additional series resistor and blocking diode should be placed between the LIN pin and the VSUP pin. See Figure 10-1
Pin 5 (RXD): The pin is an open-drain output and requires and external pull-up resistor in the range of 1 kΩ to 10 kΩ to function properly. If the microprocessor paired with the transceiver does not have an integrated pull-up, an external pull-up resistor should be placed on RXD. If RXD is connected to the VCC pin a higher pull-up resistor value can be used to reduce standby current.
Pin 6 (TXD): The TXD pin is the transmit input signal to the device from the processors. A series resistor can be placed to limit the input current to the device in the event of an over voltage on this pin. A capacitor to ground can be placed close to the input pin of the device to filter noise.
Pin 7 (nRST): This pin connects to the processors as a reset out.
Pin 8 (VCC): Output source, either 3.3 V or 5 V depending upon the version of the device.
Note:
All ground and power connections should be made as short as possible and use at least two vias to minimize the total loop inductance.