The LM3691 step-down DC-DC converter is optimized for powering low voltage circuits from a single Li-Ion cell battery and input voltage rails from 2.5V to 5.5V. It provides up to 1.5A load current, over the entire input voltage range. The LM3678 offers a 0.8V/1.2V option. One of the pair of voltages is set through the VSELECT pin.
The LM3678 evaluation board is a working demonstration of a synchronous buck DC-DC converter. The application note contains information about the evaluation board. For more details and electrical characteristics about the converter operation, please refer to the LM3678 datasheet.