The signal for the RS-232 port can vary from -12V to + 12V, and the maximum data transmission rate is 256kbps. Since this is a low speed system, there is no need to worry about the capacitance of the suppressor. Signal lines that need to be protected from ESD include RD, TD, RTS, CTS, DSR, and DTR.
As shown in the figure on the left, discrete multi-layer varistors can be used to make the board layout more flexible. To reduce the number of parts, a single rail clamp can be used.
In addition to the recommendations above, the Ruilon portfolio offers other solutions. For example, if the signal voltage is limited to -5V to + 5V, then a multi-layer varistor with a lower operating voltage can be selected.
IEC 61000-4-2 is the standard specification most suitable for this interface. This test proves that the end product is not vulnerable to ESD.
Characteristics: Not applicable.
Application warning: Not applicable.