A balloon catheter having a soft distal tip member having a non-tacky inner layer material and a soft flexible outer layer material, with both materials being readily thermally bondable to the catheter balloon. In some embodiments, a DFT apparatus may include a static random access memory cell, readwritedecoder circuitry to provide a nominal word line voltage and a nominal bit line voltage for application to the SRAM cell during accesses. The impedance circuitry may be used to measure hydration of the patient.