RFB High Current Fixed Power Inductors Coilcraft RFB High Current Fixed Power Inductors are cost-effective, high-power inductors with a 0.9µH to 18mH inductance range. The wirewound type inductors feature a ferrite core material and tin-silver over tin over copper over steel terminations with other options available. Coilcraft RFB inductors offer an ambient temperature range of -40°C to +85°C with Irms current and +85°C to +125°C with a derated current.