Medium power multilayer chip varistors

26th February 2008

AVX

ES Admin

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Medium power multilayer chip varistors from AVX Corporation are available for transient voltage suppression and ESD protection in telecommunications, designated the Telecom Series – VC14. The devices operate over -55 to 125 degrees Celsius, and meet interference requirements of telecoms equipment with a 2000 V rated test pulse of 10 x 700 µs duration as specified by CCITT or IEC 61000-4-5. For example a 60 Vrms varistor can reduce the interference voltage at the equipment connected from 2 kV to less than 200 V.

The zinc-oxide (ZnO) based, multilayer ceramic varistors feature non-linear, bi-directional voltage-current characteristics similar to back-to-back Zener diodes and an EMC (electromagnetic compatibility) capacitor in parallel. By effectively integrating this functionality into a single device the varistors require much less PCB real-estate and significantly reduce component placement costs.

Varistors offer many electrical advantages over zener diodes, including multiple strike capability without degradation, higher in rush current capability, faster turn-on-time, and inherent EMI/RFI attenuation. The varistor is also suitable for protecting devices from induced slow speed transient voltages and currents as well as ensuring negligible degradation in signal integrity.

VC14MT0600KBA has operating voltages of 60 Vrms and 80 Vdc, transient energy rating of 6 Joules (10 x 1000 µs), mean power dissipation of 0.015 W, maximum peak current of 400 A (8 x 20 µs), typical capacitance of 400 pF, and a clamp voltage of 200 V (8 x 20 µs). VC14MT0950KBA offers operating voltages of 95 Vrms and 125 Vdc, transient energy rating of 5 Joules (10 x 1000 µs), mean power dissipation of 0.015 W, maximum peak current of 250 A (8 x 20 µs), typical capacitance of 250 pF, and a clamp voltage of 275 V (8 x 20 µs). All devices have palladium-silver terminations and come in an 1812 size package.