Digi offers several options for interfacing to a low voltage (3.3V) system.
The simplest option is to use either the 9XCite or 9XTend modules with a flexible input voltage.
The modules accept power at any voltage between 2.85 and 5.5VDC.
A second option if additional range or software performance is needed is to build a low voltage interface to the XStream modules (they require a regulated 5 VDC supply.)
To facilitate using the XStream module with low voltage circuitry we provide the attached reference schematic.
Please don't hesitate to let us know how we can further assist you.