TekBox TBBT01 High Current Bias-Tee

The TBBT01 Bias-Tee is a device for measuring the saturation effects of power inductors and bias voltage effects on capacitors. The majority of available Bias-Tees for power inductor testing operate at low frequencies, rendering them unsuitable for evaluating decoupling/bias inductors of RF power amplifiers or EMC filters. However, RF Bias-Tees usually have restricted current capabilities and cannot be employed in the lower frequency region. The TBBT01 can measure high bandwidth as well as high current.

Power inductors are subject to magnetic saturation effects since they often have ferrite cores. Even before reaching the magnetic saturation current specified in inductor data sheets, the inductance begins to decrease and the RF properties of the component degenerate.

The effect of DC current is frequently underestimated while building EMC filters, and the filter fails to work as planned. High current Bias-Tees for current injection are required to assess the frequency response of an EMC-filter under load conditions.

High current bias tees can be used for a wide range of additional applications. Wherever inductors are used for decoupling and filtering in DC paths, it is best procedure to measure inductance under load current conditions. The same holds true for bias current-carrying pulse transformers.

The TBBT01 can inject up to 10A DC current into a 50 Ohm RF-path and operates at frequencies between 5 kHz and 1.5 GHz.

The TBBT01’s insertion loss is unrelated to injection current.