The combination of portable medical instruments, wireless communication technologies and Internet makes the growth of mobile medical applications possible. Taking into account the specific demands of physiological parameter detecting in mobile environment, the design of mobile medical applications faces a number of requirements, such as achieving low power consumption, low-frequency operation and low noise emissions. The present paper covers four aspects of our research work, i.e. implementation of fully differential analog front-end, power management, human body communication, and on-chip integration of digital signal co-processor. The System-on-Chip design is based on the 3-L principle: Low-frequency, Low-noise and Low-power.