Impedance mismatch in a circuit results in energy be¬ing reflected back to the source, reducing the amount of power available to the load and possibly causing damage to the power source. Matching the output impedance of the power source to the input impedance of an electrical load maximizes power transfer from source to load.
High speed data interfaces like USB, HDBaseT™, HDMI, DVI, and DisplayPort require careful consideration to ensure reliable communication that is free of disruptive EMI. Of the many tools at the designer’s disposal like trace routing, termination and component placement, the common mode filter choke remains one of the most powerful. This application note discusses the benefits of using common mode chokes and reviews the performance characteristics associated with their proper application.
Many consumer products communicate over broadband networks. From television to fiber transmission networks, the bandwidth of data communication is increasing, and the integrity of RF signals has become a major concern. This paper demonstrates how inductors are used for RF isolation in circuits ranging from relatively narrow band applications like portable devices up to broadband networks for data distribution.
In broadband bias applications, most inductors do not cover enough impedance bandwidth. Bandwidth can be increased by putting three or four inductors in series, but DC losses and filter complexity increase. Instead, a broadband bias choke provides wide bandwidth in a single inductor package.
RF inductor selection involves a number of key parameters including, mounting (surface mount or through-hole), inductance value, current rating, DC resistance (DCR), self-resonant frequency (SRF), Q factor, and temperature rating. While small size is typically desired, the laws of physics limit how small an inductor can be for a given application. Inductance value and current rating are the chief determinants of size. Once they have been calculated, other parameters can be optimized.
Modelithics Inc. and Coilcraft Inc. have teamed to develop two new Microwave Global Models™ for the Coilcraft BCL and BCR RF and microwave inductor families. Modelithics Microwave Global Models are high-accuracy equivalent circuit models that cover an entire component series within a single model.
Coilcraft's new SLR Family of high current, shielded power inductors is offered with current ratings up to 100 amps and inductance values from 85 to 370 nH, making it suitable for high frequency applications such as multi-phase VRM/VRD/EVRD regulators, Intel™ IMVP compatible systems, and GPUs/video graphic cards. The inductors also feature a tight DCR tolerance (±5.4% to ±10%) for lossless, inductor DCR-based current sensing.
Coilcraft will be highlighting their newly expanded line of BCL/BCR Series conical inductors at IMS 2015 next week in Phoenix, Arizona. The products are offered in two configurations. The BCR Series has a full-length cap to protect the coil and provide a large surface for pick and place. The BCL Series features “flying leads” to allow precise positioning and adjustment of the mounting angle.