August 2011

Inductors

Miniaturized series of gate-drive transformers

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TDK-EPC, a group company of TDK Corporation, has developed a new series of EPCOS EP5 SMT pulse transformers. They are used to couple gate-drive circuits to MOSFETs and IGBTs operating at switching frequencies within a range of 150 kHz to several MHz. These transformers are available with a wide range of turns ratios, polarities and outputs.

Thanks to the use of miniaturized EP5 cores, these transformers have dimensions of only 8.1 x 6.7 x 5.4 mm³. As several transformers are usually used in a circuit, the size reduction of the transformers results in significant space savings on the circuit board. Thanks to a special winding technology, parasitic capacitances between windings are only 25 to 95 pF, depending on the type. Stray inductances are likewise low. They range between 0.9 and 2.5 µH. Short-term dielectric strength is tested to 1500 V DC for all types of the B82804A* series. These components are designed for ambient temperatures of up to 85 °C and operating temperatures of up to 125 °C. Their terminal configuration and pin assignment correspond to the industry standard.

The main applications of these new transformers are half- and full-bridge converters as well as in frequency converters or inverters.

Glossary

  • MOSFET: metal oxide semiconductor field effect transistors, which are characterized by low losses.
  • IGBT: insulated gate bipolar transistors, which are used mainly in high-power converters. Their advantage is their low forward voltage at high current.

Main applications

  • Coupling of gate-drive circuits in half and full-bridge converters as well as in frequency converters or inverters.

Main features and benefits

  • Compact dimensions of only 8.1 x 6.7 x 5.4 mm³
  • Low parasitic capacitances of only 25 to 95 pF

Key data

Ordering code

Inductance [µH]

Outputs

Turns ratio

Stray inductance [µH]

B82804A0304A225

300

2

2.5:1:1

0.9

B82804A0324A220

317

2

2:1:1

0.6

B82804A0264A210

264

2

1:1:1

0.3

B82804A0354A110

350

1

1:1

1.0

B82804A0694A115

690

1

1.5:1

2.5

B82804A0474A125

473

1

2.5:1

1.5

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