Power Electronics

Spotlight on Passive Components

Wet Tantalum Capacitor

Vishay Intertechnology's HE3 wet tantalum high-energy capacitor features a case design with SuperTan technology for improved reliability and performance in high-energy applications. Optimized for energy-storage and pulse-power applications, the HE3 is housed in an all-tantalum, hermetically sealed case. The design provides a capacitance range of 3300 µF to 72,000 µF and features an ESR below 0.035 Ω at +25°C and 1 kHz. It offers a ±20% standard capacitance tolerance at 120 Hz and +25°C, with tolerances of ±10% also available. Pricing ranges from $250 to $750 each.
Vishay Intertechnology
Malvern, Penn

Power Resistors

IRC Advanced Film Division's MHP Series TO-247 power resistors are available in 100-W and 140-W packages. The resistors are specified for applications that require accuracy and stability. Additional applications for the MHP Series TO-247 resistors include automation test equipment, high-frequency snubber and pulse-handling circuits, motor-control and drive circuits, switch-mode power supplies and load resistors. The MHP Series resistance range is from 0.01 Ω to 220 Ω , with an inductance value below 50 nH and a voltage rating of 700 V. Absolute tolerances are to ±1% and ±5%, with absolute TCRs to ±100 ppm/°C. IRC also will produce devices outside these specifications to meet customer requirements. The power resistors are $4.58 each in quantities of 1000.
Corpus Christi, Texas


Power Capacitor Chip

A power capacitor chip (PCC) from EPCOS features a busbar that fits the IGBT modules of all well-known suppliers. At a rated voltage of 900 Vdc, the PCC offers a capacitance of 1000 µF. The ESL for the entire PCC, including the busbar, is a maximum of 15 nH. Therefore, the IGBT modules with steep switching edges do not experience any notable voltage overshoots. The cube-like design features dimensions of 280 mm × 110 mm × 120 mm.
Munich, Germany


Electrically Adjustable Resistors

Microbridge Technologies Rejustors family of low-power, low-TC re-adjustable resistors compensate and calibrate precision analog circuits. These devices are passive resistors made from the same polysilicon materials used in high-volume CMOS IC processing. The devices can be used with off-the-shelf National Instruments hardware (NI-cDAQ 9172) to calibrate a wide range of circuits in parallel. They also support operation to 125°C and 2 GHz or higher. They require no power to operate in-circuit and have no wiper resistance. They are adjustable to better than 0.1% precision. All members of the low-power family are priced at $0.99 at 1000-piece quantities.
Montreal, Canada


Power Film Resistors

Stackpole Electronics has added 30-W and 50-W offerings to the TR series of TO-220-style power film resistors. The TR series was previously offered in 20 W and 35 W configurations. This style of resistor is normally mounted along with various other power ICs to a heatsink maintained at 25°C. The TR series is available in resistance values from 50 mΩ to 10 kΩ, in tolerances as low as 0.5% and TCRs as low as 50 ppm. It is a low-inductance part with an operating voltage of 350 V.
Stackpole Electronics
Raleigh, N.C

Screw-Terminal Electrolytics

The LDG series screw-terminal electrolytic capacitors from Illinois Capacitor offer lifetimes up to 5000 hr at 85°C, with full rated voltage and ripple. The series is designed for high-reliability; high-frequency and high-ripple-current applications. The series is well suited for filtering in UPS systems, power-line conditioning, conventional or switching power supply applications, inverters and converters, and electronic welding. Its case construction and screw termination also make the series suited for mobile and in-plant applications. Parts are offered in a wide range of capacitance values and rated at a working voltage of 500 Vdc. Customization is also available. The components are 100% tested before delivery.
Illinois Capacitor
Lincolnwood, Ill

Electrolytic Capacitors

Two series of screw-terminal-type aluminum electrolytic capacitors from Boston AIC specify 8000 hr of use at 85°C with a warranty of 5000 hr at this temperature. The FX3 series of 400-V rated capacitors targets primary-side filter applications in inverters, dc servos and chopper controls. Capacitance ranges from 2200 µF in a 51-mm (d) × 96-mm (l) case to 8200 µF in a 77-mm (d) × 130-mm (l) case. Tolerance is ±20% and leakage current is 0.01 CV (µA) or 5 mA, whichever is less.

The FXW series offers similar operating life to the FX3, but with a choice of dc-voltage ratings. Capacitance values range from 13,000 µF to 38,000 µF at 350 V; 11,000 µF to 30,000 µF at 400 V; and 9000 µF to 25,000 µF at 450 V.
Boston AIC, a subsidiary of Hitachi AIC
Westborough, Mass

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