Protection from electrostatic discharge (ESD) is often an afterthought in system design even though only one ESD strike can permanently damage a device. ESD protection is a critical component in a system design. If a system does not have the correct ESD protection, the high voltage of an ESD strike through an interface connection (for example, the CAN bus) can cause a large current spike to flow directly into the transceiver device causing damage to the transceiver. This application report provides details to design isolated CAN systems with correct bus protection. The device selected to protect the transceiver from electrical overstress failures is a transient-voltage suppression (TVS) diode. TVS diodes are connected to each signal line between the interface connector (the CANH and CANL pins in this case) and ground before the transceiver device as shown in Figure 1. If an ESD strike occurs, the TVS diode breaks down and creates a low impedance path. The low impedance path diverts the current flow to ground to limit the peak voltage which protects the isolated CAN transceiver. The addition of a TVS diode can be done for a reasonable cost and with minimal additional board space.