The

∏ filter structure

AN4541

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2

The

∏ filter structure

The remaining voltage across a TVS device is linked to its clamping characteristic. Figure 2

shows the voltage across a unidirectional device versus the current flowing through it.

Figure 2. Typical clamping characteristic of a unidirectional TVS

Figure 3 and Figure 4 show how a structure with two TVSs and a resistor (or a more

complex impedance) between them can minimize the clamping voltage. The majority of the

current flows through the first TVS, while the remainder (limited by the resistor) flows

through the second, effectively reducing the clamping voltage with respect to a single TVS.

Figure 3. Positive surge