AVX adds 26Vdc varistors dual-function series

Article By : Vivek Nanda

The new MLVs respond to transient events in <0.2ns.

AVX Corp. has added 26VDC components to its dual-function TransFeed and TransFeed Automotive series of varistors. This extends the series' EMI/RFI filtering and bi-directional ESD protection capabilities to a broader range of applications, including automobiles, power supplies, computers, medical instruments, smartphones, multimedia add-on cards, barcode scanners, remote terminals, transceivers and test equipment.

The multilayer varistors (MLVs) are transient voltage suppression (TVS) devices that combine the desired electrical characteristics of AVX's robust TransGuard TVS devices with those of its feedthru capacitors in a 0805 single-chip solution. The company claims the chips respond to transient events in <0.2ns, provide overvoltage circuit protection and EMI attenuation over a much broader range of frequencies than comparable devices and deliver significant EMI attenuation when in the off-state.

 

Figure 1: TransFeed and TransFeed Automotive series MLVs use a ZnO varistor material coupled with the electrode pattern of a feedthru capacitor to maximise the package advantage of the feedthru and the material advantages of the ZnO dielectric.
 

"Both series prove especially useful in fingerprint ID and magnetic field circuits, microcontroller and interface I/O lines, and power regulation and line conditioning applications and the automotive series is also well-suited for use in drive-by-wire applications, dimming mirror circuits and LCD dashboard drivers," said Jiri Machanicek, product manager at AVX.

TransFeed and TransFeed Automotive series MLVs use a ZnO varistor material coupled with the electrode pattern of a feedthru capacitor to maximise the package advantage of the feedthru and the material advantages of the ZnO dielectric. This combination results in several electrical and physical advantages over standard ZnO MLVs, including reduced parallel inductance, increased series inductance, faster turn-on time (<250ps), broadband EMI attenuation, multiple strike capabilities and small size (relative to discrete MLV and EMI filter schemes).

Measured response times for the two series range from 200ps-250ps, which AVX claims is less than half that of the fastest bipolar TVS solutions currently available. The company also said that both series exhibit excellent attenuation at high self-resonant frequency with a much flatter roll-off characteristic than comparable devices, resulting in EMI filtering over a much broader frequency spectrum.

Rated for use in operating temperatures spanning -55ºC to 125ºC, TransFeed and TransFeed Automotive Series varistors are rated for 5.6VDC-26VDC working voltage, 18V–60V clamping voltage, 0.05J-0.3J energy, 20A-120A current, 500mA-1A feedthru current, and 0.15Ω-0.25Ω DC resistance.

The TransFeed Automotive Series is qualified to AEC-Q200, and both series are RoHS compliant. Both series are available in 0805 cases with Ni Barrier/100% Sn terminations.

They are shipped on tape and reel in quantities spanning 1,000 to 10,000. Lead-time is 14 weeks.

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