Raleigh, NC - Stackpole Electronics, Inc. recently announced the ZVY and AVY series of multilayer low voltage and automotive varistors are now capable of operating at temperatures up to 150°C, the highest operating temperature range in the industry. Previously all multilayer varistors were limited to operating at temperatures below 85°C. More recently, many applications requiring medium voltage transient protection have forced the major suppliers of varistors to improve their operating temperature range up to 125°C. However, there are still more applications requiring even higher operating temperatures. Among those applications, transient protection for automotive electronics stands out. The ZVY and AVY series of multilayer varistors (MLV) are now able to provide reliable circuit protection at these elevated temperatures.
Multilayer varistors provide protection from transient voltage surges and their associated energy and current in a response time usually less than a nanosecond. They are bidirectional devices that automatically reset themselves once the transient has passed, unlike fuses which operate in response to excessive current and don't typically reset themselves. Varistors are similar in function to both diodes and silicon based transient absorption devices. Diodes are not typically as fast in response compared to MLV and they aren't normally bidirectional. Diodes can be found with response times as fast as MLV and with bidirectional capability, but they are typically at least as expensive if not more expensive than a MLV solution. Silicon transient absorption devices have a faster response time, and have less leakage than a MLV; however they are usually much more expensive also. MLV occupy the middle ground which covers the broadest range of application requirements.
The ZVY series is available in surface mount or thru hole versions. SMD devices range from 0603 through 1206 and leaded devices range from 5 mm size to 20 mm size equivalent. DC operating voltages range from 3 to 125 volts and the ZVY is capable of handling up to 7.4 Joules standard. The AVY series is also available in surface mount and thru hole versions in a wide variety of sizes for each. They are specifically designed for 12 volt, 24 volt, and 42 volt automotive systems and are characterized for high maximum energy handling and high load dump energy, which are key parameters for automotive design engineers. Pricing for each varies greatly with size, voltage, and volume.
SOURCE: Stackpole Electronics Inc.