TYCO ELECTRONICS HAS UNVEILED RAYCHEM Circuit Protection’s new PolySwitch SMD050-2018 resettable device for telecom and networking applications. The SMD050-2018 device helps provide resettable overcurrent protection for voice-over-Internet Protocol (VoIP) and powered Ethernet equipment and is designed to meet the voltage and hold-current requirements of the IEEE802.3af Ethernet specification.

The SMD050-2018 resettable device is designed to help facilitate the development of reliable, carrier-grade VoIP systems. When installed between the power source and output of a powered Ethernet device, the SMD050-2018 device provides a second layer of defense in the power management circuit. Should any power control FET fail short, the PolySwitch device shuts down the individual port and helps prevent a system-wide power failure. Once the fault condition and power are removed, the device resets and allows the affected equipment to return to normal operating conditions. The SMD050-2018 device also helps overcome the fatigue failures, unrecoverable nuisance tripping and installation problems associated with the traditional single-use fuses.

“This device was developed in response to new circuit protection requirements as described in the IEEE802.3af powered Ethernet specification and plays a key role in the design of carrier-grade, reliable VoIP systems,” said Adrian Mikolajczak, multimedia market manager for Raychem Circuit Protection. “With an FIT of less than 0.01 when used at rated voltages, the PolySwitch SMD050-2018 device offers a new class of reliability and survivability in the field.”

The PolySwitch SMD050-2018 surface mount device is available in tape-and-reel packaging for compatibility with high-volume manufacturing. It is priced at 26 cents each in quantities of 100,000.

Beware of overselling the potential of universal fault interrupter (UFI) technology, the Federal Aviation Administration (FAA) advises. In a critique offered in response to coverage of the UFI 3000 device touted by San Diego, Calif.-based TDG Aerospace, the FAA advises that the technology’s limitations need to be weighed against its benefits (see ASW, March 22). As an example, the FAA asserts that arc fault circuit breaker (AFCB) devices will protect the entire length of a circuit, whereas the UFI will protect only what is “downstream” of the device. On the other hand, the FAA said AFCB and UFI devices, whether used separately or in combination, can enhance electrical system safety.

Below, the main points of contention offered by the FAA, with responses from TDG Aerospace:

FAA: If the AFCB is mounted in the distribution panel - and the vast majority of circuit breakers are [installed in this manner] - the entire feed to the load is protected. The UFI will only protect what is downstream of the device.

TDG Aerospace: Both AFCB and UFI are sensitive to series faults (opens) both upstream and downstream. Both AFCB and UFI are sensitive to parallel faults (line-to-line arcs and ground faults) downstream of their position. The decision on where a fault detection device should be located is highly application-dependent. For the fuel boost pump systems, it is understood that the critical portion of the circuit is the (Cont’d on p. pump itself and the local pump wiring. There is little room for de-rating protective devices for this critical application, which demands the highest levels of sensitivity and accuracy.

FAA: The UFI is applicable to three-phase circuits only. The vast majority of loads on a transport aircraft are single phase or DC powered.

TDG: While the UFI 3000 is designed specifically for the protection of the B737-300 center-tank fuel boost pumps, the UFI technology has no such limitation. It can be designed to protect two- and three-phase balanced loads, two- and three-phase unbalanced loads, three-phase loads with or without a neutral return line, single phase loads, or even DC circuits. The UFI can be tailored to operate anywhere there is current flowing in a circuit.

FAA: A UFI or AFCB device tailored for a particular load either will not function or will be prone to nuisance trips on other loads.

TDG: The UFI 3000 is application specific and is tailored to a specific load because the design application (fuel boost pumps) requires it. TDG’s proprietary technology is designed to prevent nuisance faults for each specific application. Additionally, the UFI technology allows for the detection and recording of all electrical faults - although only potentially dangerous events result in a latched condition that removes system power.

FAA: The broad applicability of AFCBs makes part inventory and selection no more problematic than conventional circuit breakers. This is not necessarily the case with UFIs.

TDG: Convenient inventory selection was not considered as a design criterion for the critical boost pump application. Rather, the UFI 3000 was designed in cooperation with both aircraft manufacturers and operators, based on their input of which capabilities would be beneficial in a fault detection device. Consequently, the UFI 3000 is enhanced with additional features such as fault phase identification and non-volatile memory that allows for downloading of relevant operating data that has been identified as beneficial for maintenance personnel.

FAA: Suggesting that UFI offers a single point solution for compliance with SFAR-88 [special federal aviation regulation on fuel system safety] is misleading and dangerous.

TDG: TDG yields to the FAA as to what is the appropriate level of protection for today’s commercial aircraft. TDG Aerospace does not seek to define the “comprehensive” solution to SFAR-88, only to provide the highest level of protection against possible electrical ignition sources.

AVX Corporation provides design engineers with technology designed to enhance both user safety as well as performance for applications in mobile communications and computer technology, portable electronics, automotive electronics and medical systems. AVX, Tele: (843) 448-9411 or www.avx.com.

Police failure to protect a prosecution witness from violence falls short of a violation of due process rights, the 1st Circuit Court of Appeals held.

Due process protections come into play only when the government “has played a role in creating the danger or has enhanced the danger to an individual,” the court said.

Iris Rivera filed a federal suit on behalf of her 15-year-old daughter, Jennifer, a prosecution witness murdered to prevent her testimony about a homicide near her home.

The Rivera family claimed the state of Rhode Island, the city of Providence, and the Providence Police Department bore the responsibility for their failure to protect Jennifer from harm.

Several days before a trial was to begin, Jennifer was shot dead in front of her house to stop her from testifying that she saw Charles Pona, the defendant in the trial, fleeing from the scene of a murder in August 1999.

Jennifer’s mother filed a federal lawsuit alleging the police had violated Jennifer’s constitutional substantive due process right to life by failing, after promising to do so, to protect Jennifer from the danger posed by the murder suspect if she agreed to testify against him.

The civil rights lawsuit named Providence Police Chief Urbano Prignano for failing to train and properly supervise his officers; and the city for having a policy and practice of not protecting endangered witnesses who were given assurances of protection.

Providence police detectives confirmed they had been repeatedly informed of the death threats made against Jennifer and promised to protect her.

But the circuit panel said Jennifer did not have a constitutional right to protection as a witness and consequently could make no claim against the government or any officer.

The three-judge panel said there is a split among the circuits on whether the government can be held responsible for witness protection. At least three circuit courts-the 6th, 7th and 9th-”have recognized the existence of a constitutional violation when, on particular facts, the state fails to protect against private violence under this state created danger theory.”

The 5th Circuit “has flatly rejected the theory” and the 4th Circuit has discussed the theory without rendering an interpretation, the 1st Circuit panel said.

Offered in 3 frame sizes from 800-5,000 A, WL Circuit Breakers feature integrated racking handles, pull apart front-mounted terminal blocks, and modular accessories. Dynamic Arc-Flash Sentry detects worker approaching energized equipment and automatically lowers trip time of breaker, minimizing potential arc-flash energy. Extended Instantaneous Protection accommodates 100% of full withstand rating of frame while allowing breaker to be applied to max interrupting rating.

ATLANTA (August 4, 2005) - Siemens Energy & Automation has expanded its line of WL Circuit Breakers with the new WL UL 489 family of insulated case circuit breakers available in three frame sizes, 800-5000 Amps. The new WL Circuit Breakers are efficient and easy to use with features such as integrated racking handles, pull apart front-mounted terminal blocks and modular accessories. The breakers have two new and exclusive features that distinguish them from their competitors and offer a safer and more reliable circuit breaker: Dynamic Arc-Flash Sentry technology and Extended Instantaneous Protection.

Due to Siemens’ unique Dynamic Arc-Flash Sentry (DAS) technology, the WL UL 489 offers a pioneering approach to arc-flash protection, meeting the stringent safety requirements of NFPA 70E. The WL UL 489 breaker, when used with an appropriate safety-rated sensing device, detects a worker approaching the energized equipment. The DAS technology then automatically lowers the trip time of the breaker and thus reduces the potential arc-flash energy. DAS capability is available on Siemens’ Electronic Trip Units 755 and 776 and can be implemented on all frames in the WL 489 circuit breaker family as well as on the current WL ANSI family.

The second new and exclusive feature is Siemens` Extended Instantaneous Protection, which accommodates 100 percent of the full withstand rating of the frame while still allowing the breaker to be applied up to the maximum interrupting rating. The WL overcomes the limitations of typical power circuit breakers by providing full withstand capability and full coordination with a minus 0% short-time band tolerance up to 85kA on frame Size II and 100kA on frame Size III.

The introduction of a new smaller size, Frame Size 1, presents increased flexibility when space is a concern. Further flexibility is offered due to the front mounted plug-in accessories that are common to the entire WL line and the field-upgradeable trip units, which allow the user make last-minute adaptations as necessary.

Reliability of the WL circuit breaker is assured with the highly accurate internal Rogowski CTs that deliver precision protection and metering with accuracy to within 1 percent. In addition, the WL 489 circuit breaker can keep in touch with the user through MODBUS or PROFIBUS communications modules, informing the user of breaker, switch, meter, relay and motor control functions. A front-panel, ready-to-close visual indicator confirms several breaker conditions are met before closing the panel giving the user peace of mind.

BSD-02 single-axis microstepping driver is suitable for driving bipolar and unipolar step motors from 50 mA to 2.5 A and up to 30 V. Amount of heat dissipated in switching IC is reduced by using 8 external discrete Schottky diodes. Driver can operate in Full-, Half-, Quarter- or Eighth-Step without requiring phase-sequence tables, high frequency control lines, or complex interfaces to program. It can be connected directly to microcontroller or PC and adjusted with on-board potentiometer.

What makes this driver different from others isour unique approach to transfer the heat from IC to a large heat sink.

Also, we were able to reduce the amount of heat dissipated in switching IC by

using eight (8) external discrete Schottky diodes (often not found on other drivers). This way we

ended up with the driver that barely needs any forced air cooling and it still costs less.

In most applications additional cooling fan will not be necessary (see user manual), what saves more money and simplifies design.

The BSD-02 module is a complete single-axis microstepping driver suitable for driving bipolar and unipolar step motors from 50mA to 2.5A and up to 30V. Requires only single power supply.

Driver can operate in one of the 4 stepping modes: Full-, Half-, Quarter- or Eighth- Step without requiring any phase-sequence tables, high frequency control lines or complex interfaces to program. Easy to use STEP/DIRECTION inputs require simple TTL signals. Can be connected directly to the microcontroller or PC

if common safety guidance are followed. Driver can be easily adjusted to virtually any motor up to 2.5A by adjusting on- board potentiometer. It may be used to drive bipolar as well as unipolar motors, 6- and 8-wire types. It will not drive 5-wire motors.

Features

o +/- 2.5A, 30V Output Rating

o Eight external Schottky diodes on board

o Crossover-Current Circuit Protection

o Under-Voltage Lockout Protection

o Thermal Shutdown Protection

o Automatic Current-Decay Mode

o Enable and Sleep Inputs

o Built-in Translator

o Translator Home State Output

o Reduced audible motor noise

o Increased step accuracy

o Low Quiescent Current (10mA MAX)

o Single power supply

o Small footprint 2.75″x2.75″

Comprised of base compound with catalyst masterbatch that promotes cross-linking, halogen-free Megolon[R] XLi710 insulates wires as small as 1 mm[sup.2] and complies with BS7211 specification for thermosetting cable insulation rated to 450/750 V. Activated by heat and water, compound is fire-retardant as well as chemical and abrasion resistant. It is suited for range of cables including copper data and telecommunication, optic fiber data, RF, and energy cables.

Windsor, Connecticut - September 19, 2005….Scapa Polymerics has introduced Megolon[R] XLi710 for wires and cables used in public facilities. Megolon Xli710 is a cross-linking, halogen free, fire retardant insulation grade compound used to insulate and sheath a wide range of cables including copper data and telecommunication, optical fiber data, radio frequency, energy and special fire survival cables.

On exposure to fire or high temperatures, Megolon compounds are difficult to ignite and generate only small amounts of pale smoke whereas PVC cables emit dense black smoke after only 3 minutes. This allows emergency exits to remain visible longer for safe evacuation. Megolon compounds are ideal for use in underground railways, airports, power stations, shopping centers and passenger ships.

Megolon XLi710 has been developed to comply with the BS7211 specification for thermosetting cable insulation rated to 450/750 volts. The material is comprised of a base compound with a catalyst masterbatch that promotes cross-linking. Designed using silane technology, Xli710 combines excellent electrical and fire retardant properties with outstanding extrusion to produce a proven stable compound with reliable consistency of performance. Activated by heat and water, Xli710 eliminates the need for cable manufacturers to invest in expensive e-beam equipment.

This cross-linkable grade possesses not only superior temperature performance and enhanced tensile strength, but also increased chemical and abrasion resistance. It can be used to insulate wires as small as 1mm[sup.2].

The TF 600 nonresettable fuse is designed to protect telecommunications equipment against power crossing and lightening surges.
New from Schurter, the TF 600 nonresettable fuse is designed to protect telecommunications equipment against power crossing and lightening surges. The fuse meets the requirements outlined in North American standards Telcordia GR-1089, TIA-968-A (formerly FCC Part 68), and UL 60950, as well as the international standards ITU-T K.20 and IEC 60950. The fuse has a rated breaking capacity of 60A at 600V AC, over a current range of 0.5-2A.

The TF 600 is RoHS compliant according to Directive 2002/95/EC.

Its low profile and small footprint conform to industry norms for sise, placement and process compatibility.

Its time-lag tripping characteristic provides reliable secondary protection of secondary circuits in a variety of telecomms systems and networking equipment designated for use around the world.

Typical applications are customer premises equipment (CPE) like telephones and modems, high-speed transmission equipment like ADSL modems and splitters and analogue line cards (SLICs).

The TF 600 is built to UL248-14 and carries UL/CSA recognition.

It also holds a ‘Free of CCC’ confirmation for China.

It is supplied either on tape (2000 pieces) or loose in a bag (100 pieces).

The RClamp0504N is a 5.0V protection device aimed at next-generation monitors, laptops, television set top boxes and networking equipment using high-speed I/O protocols.
New from Semtech, the RClamp0504N is a 5.0V protection device aimed at next-generation monitors, laptops, television set top boxes and networking equipment using high-speed I/O protocols. The RClamp0504N measures a mere 2.0 x 2.0 x 0.6mm. It features an array of surge-rated steering diodes and a low voltage TVS diode and protects up to four data lines.

The device’s low capacitance of 3pF (typical) allows it to operate with no insertion loss to 1GHz.

The advent of USB 2.0, gigabit Ethernet, DVI and other high-speed data protocols has created a greater need for protection from cable discharge events (CDE) - the insertion of a statically charged connector - that can cause a system failure.

The RClamp0504N features a fast response time, low inductance and greater electrostatic discharge (ESD) protection for these applications.

‘CDEs are becoming a huge issue for electronics makers, because without the right protection for higher speed I/O lines, they could see an increase in warranty claims when transient electricity destroys a key component’, said Tom Dugan, Semtech’s Director of Protection Products.

‘The RClamp0504N gives these products the ESD protection they need to alleviate this problem, along with a small form factor that allows designers to be creative with how to protect their systems - by putting the protection in the connector, for example’.

The device is in Semtech’s leadless package design, which is 66% smaller than the leading industry solution.

That small package size is a result of Semtech manufacturing process advances that shrink the semiconductor features and enable the single-die design.

The small size also means the device can be used in USB or Ethernet cable connectors, protecting monitors, laptops and other small systems where board space is at a premium.

RClamp0504N is part of Semtech’s RailClamp protection device family, which includes the SRV05-4.

The SRV05-4 is an established leader in low voltage protection devices.

It had been used in many applications including laptop computers where high-speed ports are prevalent.

The RClamp0504N is designed for next generation designs where the requirement for small form factor is critical.

This device replaces the SRV05-4 where board space is limited.

RClamp0504N is designed to meet the following IEC requirements: IEC61000-4-2 (ESD) +/-15kV (air) and +/-8kV (contact), IEC61000-4-4 (EFT) 40A (5/50ns), and IEC61000-4-5 (lightning) 12A (8/20us).

The lead-free design of the device complies with the European Union’s RoHS Directive to meet worldwide environmental and regulatory requirements.

The Telegartner range of coaxial surge suppressors is designed particularly for use in wireless LAN applications with SMA, R-SMA, TNC, R-TNC and N connectors.
New from Quadrant, the Hertfordshire based connector and cable component distributor, is the Telegartner range of coaxial surge suppressors designed particularly for use in wireless LAN applications with SMA, R-SMA, TNC, R-TNC and N connectors. Aimed for use in coaxial transmission lines to suppress high impulses that can be generated by lightning strikes, Telegartner offers three types of protection devices allowing users to choose the most suitable depending upon the application. The 2.5GHz high power series uses a gas discharge tube type suppressor and is capable of a discharge current of up to 40kA, and the WLAN series, although based on a similar design, is more compact and has a wider operating frequency of up to 6.0GHz.

Although discharge current is limited to 10kA it is ideal for WLAN and similar applications.

Quadrant also supplies suppressors with a direct, solid short circuit between inner and outer conductors that provide extremely high discharge currents of over 100kA and are suitable for applications such as mobile telephone networks (GSM,UMTS and Tetra).