MOV planar arrays protect against transient events

Incorporated into the connectors on the external wall of the subsystem, the devices are used to protect the increasing volume of sensitive electronic circuitry found in today's complex systems.

'Potentially damaging voltage spikes need to be suppressed or grounded sooner rather than later,' said Chris Noade, marketing manager, Syfer Technology.

'Relying on PCB-based transient voltage protection means that the spike is already inside the box.

'Filtered connectors provide the ideal means of stopping the spike on the outside,' he explained.

With multiple, interconnected 'black boxes' it is vital that spikes are not allowed to propagate from one unit to the next.

Syfer's application-specific MOV planar arrays are typically built into military-style filtered connectors, including circular shell sizes eight to 24, Arinc 600 and 404 series, as well as rectangular 24308 series and regular, sub-miniature and micro D types.

Planar array technology has the added advantage of weight and volumetric efficiency over other transient protection or capacitor devices.

MOVs are suitable for protecting against several types of transient event.

With a material response time of less than 500ps, no leads/tracks and a low inductance geometry, MOVs are more than capable of suppressing lightning induced transients.

The devices are also suitable for protection against voltage spikes caused by power supply glitches and noisy switching circuits.

Operating over the full military temperature range from -55C to +125C, the devices are specified with leakage current of 5uA at +25C, 50uA at +125C, and with maximum working voltages from 10 to 45V DC, and 7V to 35V AC.

Capacitance, measured at 1Vrms at 1kHz, depends on working voltage, platform, hole size and unit thickness, but typically ranges from 3nF at 10V DC, 7Vrms to 500pF at 45V DC 35Vrms.

In operation, the MOV acts as a high-value resistor, such that once the voltage reaches a certain value, the device becomes highly conductive and provides a fast and efficient short-circuit route to ground to limit surges or pulses, and dissipating potentially destructive energy as heat.

With the MOV planar array's inherent capacitance, it can be used as a simple C filter or as one half of a Pi or unbalanced Pi filter.

When used together with Syfer's capacitor planar arrays, the MOV planars can provide a complete over-voltage transient protection and EMI filtering solution to connector manufacturers.

Devices are RoHS compliant.

Syfer works closely with OEM customers and connector manufacturers to provide custom products meeting exact requirements.