In Figure 30, the ultra low-power microcontroller, MSP430G2132, controls the I2C data traffic of configuration data and conversion results for the analog inputs and outputs. Low-power data converters build the analog interface to sensors and actuators. The ISO1541 device provides the required isolation between different ground potentials of the system controller, remote sensor, and actuator circuitry to prevent ground loop currents that otherwise may falsify the acquired data.
The entire circuit operates from a single 3.3-V supply. A low-power push-pull converter, SN6501, drives a center-tapped transformer with an output that is rectified and linearly regulated to provide a stable 5-V supply for the data converter.