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TransGuard

®

AVX Multilayer Ceramic Transient Voltage Suppressors

GENERAL DESCRIPTION

The AVX TransGuard

with unique high-energy multilayer construction represents

state-of-the-art overvoltage circuit protection. Monolithic

multilayer construction provides protection from voltage

transients caused by ESD, lightning, NEMP, inductive switch-

ing, etc. True surface mount product is provided in EIA

industry standard packages. Thru-hole components are

supplied as conformally coated axial devices.

TransGuard

semiconductor devices with non-linear voltage-current charac-

teristics (bi-directional) similar to back-to-back zener diodes.

They have the added advantage of greater current and energy

handling capabilities as well as EMI/RFI attenuation. Devices

are fabricated by a ceramic sintering process that yields a

structure of conductive ZnO grains surrounded by electrically

insulating barriers, creating varistor-like behavior.

The number of grain-boundary interfaces between conduct-

ing electrodes determines “Breakdown Voltage” of the

device. High voltage applications such as AC line protection

require many grains between electrodes while low voltage

requires few grains to establish the appropriate breakdown

voltage. Single layer ceramic disc processing proved to be a

viable production method for thick cross section devices

with many grains, but attempts to address low voltage

suppression needs by processing single layer ceramic disc

formulations with huge grain sites has had limited success.

AVX, the world leader in the manufacture of multilayer

ceramic capacitors, now offers the low voltage transient

protection marketplace a true multilayer, monolithic surface

mount varistor. Technology leadership in processing

thin dielectric materials and patented processes for

precise ceramic grain growth have yielded superior energy

dissipation in the smallest size. Now a varistor has voltage

characteristics determined by design and not just cell sorting

whatever falls out of the process.

Multilayer ceramic varistors are manufactured by mixing

ceramic powder in an organic binder (slurry) and casting it

into thin layers of precision thickness. Metal electrodes are

deposited onto the green ceramic layers which are then

stacked to form a laminated structure. The metal electrodes

are arranged so that their terminations alternate from one

end of the varistor to the other. The device becomes a

monolithic block during the sintering (firing) cycle providing

uniform energy dissipation in a small volume.