Pin 1 (RXD): The pin is an open-drain output and requires an external pull-up resistor in the range of 1 kΩ to 10 kΩ to function properly. Note that the minimum value will depend on the VIO supply used. See IOL in electrical specifications. If the microprocessor paired with the transceiver does not have an integrated pull-up, an external resistor should be placed between RXD and the regulated voltage supply for the microprocessor.
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 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 case of an over voltage fault.
Pin 3 (NC): Not Connected.
Pin 4 (TXD): The TXD pin is used to transmit the input signal from the microcontroller. A series resistor can be placed to limit the input current to the device in the case 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 5 (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 6 (LIN): This pin connects to the LIN bus. For responder mode applications, a 220 pF capacitor to ground is implemented. For commander mode applications, an additional series resistor and blocking diode should be placed between the LIN pin and the VSUP pin. See Figure 10-1.
Pin 7 (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 8 (NC): Not Connected.
All ground and power connections should be made as short as possible and use at least two vias to minimize the total loop inductance.