8.2.2.6 Diodes

For transient voltage protection, a 40-V bidirectional transient voltage suppressor (TVS) diode is placed across the BUS lines of the design. Certain criteria should be considered when making this diode selection, such as the diode’s working voltage, breakdown voltage, leakage current and power rating. In addition to these parameters, leakage current should also be factored into the design as it will impact the accuracy of the analog current loop.

2-wire polarity protection is also employed by using the DSRHD10 as a diode bridge rectifier. The placement of this component ensures that the current loop will always correctly operate regardless of the arrangement of input connections. As with other elements, leakage and biasing voltage should be considered as it will affect system accuracy and compliance voltage.