Electronic Design


Single-Phase Bridge Rectifiers Target Power-Supply Input Circuits
The 25-A GBPC25 and the 35-A GBPC35 bridges combine four rectifier diodes into a single full-wave bridge rectifier for high-current power-supply input circuits. Rated up to 1200 V, they're made with glass-passivated diode chips for maximum high-temperature reverse-blocking (HTRB) stability. They come with industry-standard pinouts and universal three-way terminals to facilitate fast connection, board mounting, and soldering. A wire lead version is available as well.

These single-phase bridge rectifiers cost $2.40 each in 100-unit batches.

International Rectifier, 233 Kansas St., El Segundo, CA 90245; (310) 252-7105; www.irf.com.

Step-Down DC-DC Converters Provide 600 mA Of Output Current
The LTC1877 and LTC1878 step-down dc-dc converters feature two internal switches in an 8-lead MSOP package. Each converter delivers up to 600 mA of output current with 95% efficiency while drawing only 10 µA of supply current under no load conditions, or 1 µA in shutdown. Also, they operate at a constant frequency of 550 kHz. Users can synchronize them to an external clock from 400 to 700 kHz, facilitating the suppression of switching harmonics in sensitive IF bands.

Both offer selectable Burst Mode operation, whereby the internal power MOSFETs operate intermittently based on load demand. A 0.8-V feedback reference voltage supports low output voltages. The LTC1877 can be used in one- or two-Li-ion cell applications with a 2.65- to 10-V input voltage range. The LTC1878 has a 2.65- to 6-V input voltage (single Li-ion cell). According to their manufacturer, they're well-suited for a host of battery-powered applications that require a 1- to 2-W output.

The LTC1877 and LTC1878 cost $2.90 and $2.60, respectively, in 1000-unit quantities.

Linear Technology Corp., 1630 McCarthy Blvd., Milpitas, CA 95035-7417; (408) 432-1900; fax (408) 434-6441; www.linear-tech.com.

Miniature 1-W DC-DC Converters Feature 1000-V DC Isolation
Models in the SWU.1 line of 1-W dc-dc converters come in a 4-pin sip package that measures 0.23 by 0.45 by 0.39 in. These encapsulated devices also operate without derating over their full specified temperature range. Single output voltages of 3.3, 5, 9, 12, and 15 V dc are available. Input voltages of 3.3, 5, 12, 24, and 48 V dc (±10%) are available as well. They also feature 75% typical efficiency, 1000-V dc isolation, ±5% voltage accuracy, and a 0°C to 70°C operating-temperature range.

According to their manufacturer, they can be used in all I/O board systems and subsystem distributed power configurations where low-voltage semiconductors are involved. They're designed for use in portable test equipment, telecommunications, local power networks, process control instrumentation, and other EMI-sensitive applications. All units are 100% burned in under full load, high-pot tested, and final-electrical tested prior to shipment.

In 1000-unit quantities, these converters cost $5.95 each. Average delivery takes three weeks.

Polytron Devices Inc., P.O. Box 398, Paterson, NJ 07544; (973) 345-5885; fax (973) 345-1264; www.polytrondevices.com.

Customizable Power Supplies Come In 3U Rack Configurations
The bulk front-end switching power supplies in the HPS series are very customizable. They come in 5.25-in. (3U) rack configurations that can house up to four individual modules with a choice of single dc outputs from 24 to 60 V dc and power ratings of 1000 and 1250 W for a 5000-W maximum total rating. Each module features universal 85- to 264-V ac input. Also, each module accommodates frequencies from 47 to 440 Hz with a 0.99 power factor that meets EN61000-3-2 limits for input current harmonics.

The HPS rack includes a smart-power interface in the form of a slot at the side of each rack. This slot accommodates standard cards that can include RS-232 communications, current limit, fan controls, and other features possible with the unique microprocessor interface. The microprocessor enables communications features that permit digital temperature monitoring and storage of unique serial numbers or other product identification or status data. Manufacturing meets ISO9001 quality process standards.

Evaluation units in 3U configurations are now available. Production units are slated for September delivery. Pricing starts at $376 per module and $205 per rack.

Astec America Inc., 5810 Van Allen Way, Carlsbad, CA 92008; (760) 930-4600; fax (760) 930-0698; www.astec.com.

Modular Inverter Simplifies Fuel-Cell Power And DC-AC Conversion
The FCE series of modular, scalable 5.0-kVA dc-ac pure sinewave inverters is designed for residential, vehicular, and industrial fuel-cell applications with widely varying output load requirements. Its high-frequency pulse-width modulation (PWM) technology "synthesizes" a precision-regulated sinusoidal output with less than 2% harmonic distortion. Capable of parallel and synchronized operation, users can configure units to provide single- or three-phase ac output.

These inverters have a 160- to 300-V dc input range. Consequently, they can operate within the charge and discharge limits of any fuel cell or battery bank. The FCEs provide an MTBF of over 100,000 hours in a hot-bus plug-in modular form factor for reliable, redundant ac power. They come in a standard 19-in. rack that accepts two 5.0-kVA FCE inverters for a combined 10-kVA output, or true N+1 redundant ac power. And, they feature a voltage and current monitor, input and output good signals, and a summary fault signal.

Pricing starts at $2750 in OEM quantities. Typical delivery for standard units is three to four weeks.

TDI Transistor Devices, 85 Horsehill Rd., Cedar Knolls, NJ 07927; (973) 267-1900; fax (973) 267-2047; www.tdipower.com.

PFC Power Supply Provides 40 A Of Current With Dual Outputs
The PFC250-4530 quad-output, 250-W power supply provides high-current outputs of 3.3 V at 20 A and 5 V at 40 A for systems with mixed-mode high-speed logic. Its active power factor correction (PFC) meets the EN61000-3-2 and EN60555-2 power-line harmonic requirements. Two available "floating" 12-V outputs at 6 and 3 A may be connected as positive or negative outputs or in series to provide 24 V at 3 A.

Its output current sharing, which is within 10% on the 5- and 3.3-V outputs, permits paralleling of the power supply for use in N+1 redundant applications and scalable configurations. The supply also includes remote sense on the 5- and 3.3-V outputs, a dc power-good signal, an ac power-fail signal, and a logic inhibitor. Overvoltage, overcurrent, and overtemperature protection are featured as well. With an 8.5- by 4.75- by 2.0-in. package, the PFC250-4530 has a 3.1-W/in.3 power density.

This power supply costs $231 in quantities greater than 250 units. Production quantities are available in six to eight weeks.

Power-One, 740 Calle Plano, Camarillo, CA 93012; (800) 678-9445, (805) 987-8741; fax (805) 388-0476; www.power-one.com.

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