Lightning Arrestors Protect Wi-Fi and WiMAX Applications
The QS 400 series of SurgeGuard™ quarter wave stub lightning protectors from NexTek, Inc. has been crafted especially to provide protection for Wi-Fi and the WiMAX applications, exceeding the specifications in the 802.11, UNII, ISM, and MIL-STD-202 standards. The devices safeguard wireless products operating in frequencies ranging from 2.4 GHz to 6 GHz. Measuring 6.22 mm x 32 mm in diameter, they feature bi-directional protection, low VSWR (1.05 typical), normal and reverse polarity, high RF power, and ultra-low let-through. Constructed with robust materials, the QS 400 series is waterproof to IP68 standards and can withstand multiple strikes as well as very high transients up to 60 kApk. The series is available in various coaxial connector and gender configurations. Learn more at the NexTek website.
Transient Voltage Surge Suppressors Withstand Harsh Environments
PowerTrip® SPDs (surge suppression devices) from Alltec Corporation utilize a unique “discrete all-mode protection” to control transients by eliminating the transient voltage difference between all of the mode combinations, thus eliminating susceptibility to transient current flow. When transient episodes occur, the SPD immediately bonds every wire combination to the same potential, instantly creating an equi-potential bond. PowerTrip devices control voltage transients for all conductor combinations. Other product features include the capability of withstanding repeated transients, fast recovery times, tight nominal clamping levels, and sine-wave tracking and EMI/RFI filtering capabilities. More product information can be found on the Alltec website.
Protection Array Safeguards USB-OTG Bus Ports
The VBUS053AZ-HAF from Vishay Intertechnology is a compact ESD protection array with low capacitance and leakage current to protect USB-OTG ports against transient voltage signals. The device has three lines of USB ESD protection at a 5.5-V working range and one line of VBUS protection at a 12-V working range. Packaging is leadless LLP75-7L with a 1.6-mm by 1.6-mm footprint with a profile of 0.6 mm, thus conserving board space in small electronic applications such as cell phones, portable gaming systems, and MP3 players. Low load capacitance is 0.7 pF for the three data lines—D+, D-, and ID. Maximum leakage current is 0.085 µA at the working voltage of 3.3 V and 1 µA at 5.5 V. The VBUS053AZ-HAF offers a low maximum clamping voltage of less than 4.1 V at 3 A for the data lines and less than 8 A for the VBUS line. The device provides transient protection as per IEC 61000-4-2 (ESD) at 15 kV (air and contact discharge)—as well as IEC 61000-4-5 (lightning) from 3 A. Learn more at the Vishay website.
Hand-Held ESD Simulator Tests to Relevant Standards
The MiniZap® from Thermo Scientific is a battery-operated, hand-held 15-kV ESD simulator for performing contact mode and air discharge mode testing. Allowing for the testing of products at the system level, the MiniZap allows users to meet both the 0.7-ns rise time requirements of IEC 61000-4-2 and to perform “real world” testing with faster rise times to determine a product’s actual survivability in its intended environment. The MiniZap will also meet the requirements of waveform purity when verified using a wideband instrument. This device is capable of up to 15 kV air and 8.8 kV contact testing. It performs compliant-level ESD testing in accordance with IEC 61000-4-2 and ANCI C63.16. Look for more product information on the Thermo Scientific website.
Simulation Software Models Lightning Strikes
ELECTRO Version 7 from Canada-based INTEGRATED Engineering Software now includes a new feature for its field solver software, which accurately models transients such as lightning strikes. This feature was developed to meet the needs of scientists and engineers who design high voltage applications such as shielding, cables, transformers, insulators, and arrestors. The new feature in Version 7 also supports analysis of full wave impulse transient sources. These classes of failures result not from lightning strikes but from squirrels entering high voltage equipment areas. The software allows testers to project how equipment will function when impacted by a large amount of excess voltage, such as that resulting from a lightning strike. This approximation obviates the need for testing using an actual prototype, an option that might be extremely difficult and expensive, if not impossible. This new version also allows testers to enter impulse parameters directly without the need to solve complex equations. ELECTO can also be used to model difficult transient simulations, such as those involving 27-kV systems, which are required to withstand electrical impulses of 127 kV without sustaining damage.
Air Gap Technology Helps Achieve Low Capacitance
Two new ESD suppression devices from Stackpole Electronics are high-speed and ultra high- speed transient suppression chips with an 8-kV protection level for direct contact and a 15-kV level for air. Chip array versions of these devices, ESA/ESAU, come in 0603 x 4 chip array size, while the EDS/ESDU series comes in 0402 and 0603 chip sizes. These two series are well suited to providing USB 2.0 and IEEE 394 port protection for notebooks, PCs, cell phones, PDAs, digital cameras, plasma display panels, HDTVs, or any device with high-speed data ports. All these devices employ air gap technology that achieves 0.2 to 0.05 capacitance and response time below one msec.
