LPR Mini Transformers Coilcraft LPR4012 and LPR6235 Mini Transformers offer excellent coupling coefficient (k=0.95), making them ideal for use in a variety of applications such as step-up, resonant, and flyback applications. These devices feature high Isat and low DCR ratings that provide high efficiency and ideal current handling in a rugged, cost-effective design. Coilcraft LPR4012 and LPR6235 Mini Transformers utilize plating with matte tin over nickel over silver, which improves solderability and removes halogens.