With proper board and connector layout and balancing of the transmission media

Newer-generation transceivers typically don’t employ externally controllable slew rate control, but are rather designed to better match the CANH and CANL output currents before, during, and after transitions between dominant and recessive states and back. With proper board and connector layout and balancing of the transmission media, it’s possible to achieve very low emissions using a newer generation of transceiver without the addition of a common mode choke. One termination technique that can provide significant improvement in emissions is to split the termination resistor and add capacitance to the center, or common mode point, as shown in Figure 6.

Figure 6. Typical CAN node configuration.Typically, a larger capacitance leads to a flatter VOC signal and a larger benefit in reducing emissions. This adds capacitance to the node, however, and has to be traded off versus maximum node load requirements. This capacitor also provides an AC path between ground and the common mode node, which could be an issue if there is ground noise on the module. When using an ISO-11898-5 transceiver, laptop battery the SPLIT pin output may also be connected to the common mode termination point to provide a small stabilization benefit as noted earlier.

In the context of this article, immunity is considered to broadly cover transceiver robustness to several different defined noise sources including bulk current injection (BCI) , direct power injection (DPI), electrostatic discharge in all its forms, automotive transient pulses according to ISO-7637, and bus pin opens and shorts to ground or VCC. Application of these stresses and required transceiver performance levels vary by industry standards as well as OEM EMC specifications. Design of a robust CAN transceiver must take into consideration continued operation under BCI and DPI stresses and survival under the remaining stresses. Dell wu946 battery Dell XPS M1210 battery Dell XPS M1330 battery Dell XPS M1530 battery