Bourns develops an improved gas discharge tube

Bourns, Inc. has improved its next-generation gas discharge tube (GDT) line with a 3-electrode surface mount product family. Claiming breakthrough overvoltage surge arrestor performance, the new Model GDT35 Series offers a significantly higher level of protection against voltage transients caused by lightning or accidental contact with AC power lines, resulting in a faster responding component.

Bourns develops an improved gas discharge tubeBourns said it developed the next generation of GDTs with improved impulse Voltage protection and higher surge ratings to meet increased market demand as susceptibility to surges increased with smaller components, calling for smaller and more effective overvoltage protection solutions.

“Legacy GDTs with higher impulse sparkover voltage ratings may allow let-through voltages that could damage the downstream components – especially more compact, newer generation components,” said Bourns.

The 3-electrode GDTs are based ON Bourns’ proprietary, advanced computer simulation techniques, which led to a lower impulse sparkover component design that reduces stress on downstream components, said Bourns. This enables designers to select smaller and lower voltage-rated components, reducing the bill-of-materials costs.

The key features of the GDT35 series are the high surge rating, lower impulse breakdown and lower capacitance. “The GDT35 series’ higher surge rating in a smaller footprint contributes to smaller board real estate. The lower impulse breakdown enables the device to better protect against voltage let through, and with high frequency communication or signal, lower capacitance leads to lower insertion loss,” according to Bourns’ product managers.

The GDT35 GDTs feature a unique coplanarity fit that enables the devices to toggle in either direction until a three-point contact is established. It also is said to deliver “superior” current handling capability in a small 5 × 7.2-mm form factor. (See the datasheet for specs by part number.)

Also, the low capacitance (< 0.7 pF) and low insertion loss make the devices suited for protecting industrial equipment and high-speed information and communication technology systems. Other key specs include a DC breakdown voltage range of 75-600 V and an extended temperature range of -55°C to 125°C to meet tough environmental conditions.

How does the GDT35 devices work? “A fast-rising event promotes charge emission in the GDT35 series’ auxiliary electrodes. These charges ionize the inert gas inside the GDT35 in less than 1 microsecond. This momentarily highly ionized state has exceptionally low impedance, limiting the voltage because of this transition,” said Bourns.

The Model GDT35 series also is a drop-in replacement option for the Model 2036-SM GDT Series. The company introduced its next-generation 2-electrode 5-mm GDT25 series two years ago.

Available now, the GDT35 Series is UL recognized and Rohs compliant. A GDT35 Design Kit for prototyping is available. It contains five pieces of each GDT35 Series voltage.


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