Creepage distances according to IEC 60664 (basic insulation)

Qualified to AEC-Q200

TDK Corporation presents two new series of EPCOS SMT current sense

transformers for power electronics. The various types in the B78417A*

series are based on EP7 ferrite cores, have compact dimensions of just 10.6 mm x 12.2 mm x 11.0 mm and are

designed to measure pulse currents of up to 20 A. The maximum DC resistance on the primary winding is 1.9 mΩ. The

SMT current sense transformers in the B78419A* series are designed with EP10 ferrite cores. These components have

dimensions of 12.8 mm x 13.6 mm x 14.4 mm and their measurement range extends up to 30 A. The DC resistance is

just 0.5 mΩ.

Each series is available with a variety of turn ratios: While the EP7-based transformers are available in four versions

with turn ratios of between 1:50 and 1:125, the EP10 transformers offer five versions with turn ratios of between 1:50

and 1:180. The permissible operating temperature range extends from -40 °C to +150 °C. The transformers are

suitable for measuring currents in the frequency range from 50 kHz to 250 kHz.

Possible applications include switch-mode power supplies and all types of converters. The test voltage between the

primary and secondary sides is 2400 V AC and the creepage distances meet the requirements for basic insulation

according to IEC 60664. As the components are qualified to AEC-Q200, they can also be used in xEV applications,

e.g. for measuring the currents in DC/DC inverters.

Main applications

Switch-mode power supplies and all types of converters

DC/DC inverters in xEV applications

Current measurement in 48 volt on-board power supplies

Main features and benefits

Wide measuring range up to 30 A

Low ohmic resistance

Creepage distances according to IEC 60664 (basic insulation)

High dielectric strength for compact design

Qualified to AEC-Q200

Wide range of turn ratios

Key data

Transformers February 2016

Compact SMT current sense

transformers for power

electronics

Type Dimensions

[mm]

Max. DC

resistance

primary winding

[mΩ]

Max. current

[A]

Turns

ratio

B78417A2285A003 10.6 x 12.2 x 11.0 1.9 20 1:50

B78417A2286A003 10.6 x 12.2 x 11.0 1.9 20 1:70

B78417A2185A003 10.6 x 12.2 x 11.0 1.9 20 1:100

B78417A2287A003 10.6 x 12.2 x 11.0 1.9 20 1:125

B78419A2288A003 12.8 x 13.6 x 14.4 0.5 30 1:50

B78419A2289A003 12.8 x 13.6 x 14.4 0.5 30 1:70

B78419A2251A003 12.8 x 13.6 x 14.4 0.5 30 1:100

B78419A2290A003 12.8 x 13.6 x 14.4 0.5 30 1:125

B78419A2271A003 12.8 x 13.6 x 14.4 0.5 30 1:180

Products & Technologies