Electronic Design

Circuit Protection Devices

Resettable Fuse Offers Overcurrent Protection For MDF Modules
The TSV250-130 PolySwitch surface-mount polymeric positive temperature coefficient (PPTC) resettable fuse provides overcurrent circuit protection for main distribution frame (MDF) modules and dense linecards supporting multiple transmission lines. This fuse features a vertical configuration and a 50% smaller footprint than other TS250 products.

According to the company, the TSV250-130 helps OEMs meet ITU-T K.20 recommendations and regional post, telegraph, and telephone (PTT) requirements for primary protection modules. It features a hold current of 130 mA and a 1.5-kV lightning withstand. It also offers 250-V power cross interrupt ratings. According to the company, this device suits high-speed communication applications, such as DSL.

The device is available in tape-and-reel packaging for compatibility with high-volume manufacturing. It is also available in resistive binned packaging for applications with more stringent line balance requirements. The fuses are now available and start at $0.30 each.

Raychem Circuit Protection, 300 Constitution Dr., Menlo Park, CA 94025-1164; (800) 227-7040; www.circuitprotection.com.

Expanded Fuse Line Includes Miniature SMT PPTCs
The Multifuse product line has been expanded to include miniature SMT polymeric positive temperature coefficient (PPTC) fuses and high-current SMT PPTCs. Members of the MF-USMD family of SMT resettable fuses have a 1210-mil footprint. They offer overcurrent protection for a variety of applications, including motherboards, add-on cards, disk drives, and handheld devices. While they feature trip times of less than 0.3 s, voltage ratings range from 6 to 30 V.

Members of the MF-MSMD family of PPTC resettable fuses offer hold currents of 1.25, 1.5, 2.0, and 2.6 A. They feature an 1812/4532 footprint for high-density board applications. While internal resistance ranges from 30 to 60 mΩ, voltage ratings range from 6 to 8 V. Devices with higher currents use the company's multilayer technology to maintain an 1812 footprint.

Devices in the MF-VS line of battery strap protection devices offer resistance values of 18 to 30 mΩ. According to the company, these devices give designers of polymer-lithium and lithium-ion battery packs greater flexibility in circuit design. They also feature trip temperatures of 85°C. Optional hold currents are 1.7 and 2.4 A. Lead lengths can be customized for specific applications. All devices are UL, CSA, and TUV approved.

In 3000-unit quantities, the MF-USMD PPTCs start at $0.25 each. In 1500-unit quantities, the MF-MSMD PPTCs start at $0.28 each. The MF-VS protection devices start at $0.25 each in 500-unit quantities.

Bourns Inc., 1200 Columbia Ave., Riverside, CA 92507; (909) 781-5500; fax (909) 781-5006; www.bourns.com.

Basestation Lightning Protectors Available In Various Configurations
Members of a line of wireless basestation lightning protection solutions are available in a number of configurations. Both gas-filled tube and quarter-wave solutions are provided.

Optional configurations include bulkhead, pigtail, and in-line types. All are available with both "N" or "7-16" connectors. Band-specific and broadband versions of the devices are offered.

Prices range according to product configuration and quantity ordered. While the quarter-wave devices begin at $75, the tube-type versions start at $60.

Spinner North America, 6350 Regency Pkwy., Ste. 500, Norcross, GA 30071; (770) 263-6326; www.spinnerna.com.

Manual Motor Controllers Suit Industrial Applications
Members of a line of UL508 listed and CSA certified manual motor controllers (MMCs) offer motor disconnect means. The UL508 listing enables licensed electricians to use the manual MMCs/miniature circuit breakers (MCBs) without first obtaining the approval of a UL inspector.

These thermal/magnetic-type manual motor controllers are used to protect the wiring and loads of electrical circuits against thermal overload and magnetic short circuit. According to the company, suitable applications include ac across-the-line motor starting, ac general use, ac resistance, ac discharge lamps (ballast), and ac incandescent lamps (tungsten). Motor branch circuit applications include manual motor controller, disconnect means, a combination of controller and overload protection, and a combination of controller and motor disconnect means.

The trip characteristics offered include B, C, D, E, F, G, and Z. Options include 1-, 2-, and 3-pole and 1- or 3-pole neutral configurations. All trip curves offer electrical ratings of 0.3 to 60 A.

The MMCs/MCBs are now available. Prices range from $18.50 to $100.

Altech Corp., 35 Royal Rd., Flemington, NJ 08822; (908) 806-9400; fax (908) 806-9490; www.altechcorp.com.

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