TCM Surface-Mount RF Transformers Mini-Circuits TCM Surface-Mount RF Transformers feature an ultra-wide bandwidth with good return loss and excellent amplitude and phase unbalance capability. The RF transformers provide an aqueous washable plastic base with solder-plated leads. The TCM series is ideal for various applications, including impedance matching, push-pull amplifiers, Wi-Fi®, and more. The Mini-Circuits TCM Surface-Mount RF Transformers also offer models with Top-hat® capability, which allows faster pick-and-place functions and enables visual identification marking.