Pin 1 (RXD): The pin is an open-drain output and requires an external
pull-up resistor in the range of 1kΩ to 10kΩ to function properly. Note that the
minimum value depends 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 if there
is 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 220pF 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 8-1.
Pin 7 (VSUP): This is the supply pin for the device. A 100nF decoupling
capacitor should be placed as close to the device as possible.
Pin 8 (NC): Not Connected.
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.