The main voltage supply for this device is on the VCC pin. The VCC pin can be supplied either by a 3.3-V or 5-V regulator. This pin is protected internally from possible negative voltages on the pin and from possible back-feeding of current from the device to the regulator. The pin can also withstand voltages as high as 30 V. For 3.3-V mode, the VREG and VCC pins are shorted together on the PCB.

There is an internal 3.3-V regulator with a capacitor on the VREG pin. This regulator is the supply for all internal blocks, the LC oscillator, and the regulator is also used as a reference block for various sections of the signal chain. Additionally, an internal 1.5-V regulator supplies the digital logic. This device has two modes of operation: a 5-V supply mode and a 3.3-V supply mode. For 5-V supply mode, 5 V is required on the VCC pin that the internal regulator will use to generate voltage on VREG. For 3.3-V supply mode, the VREG and VCC pins must be connected externally and supplied with regulated 3.3 V. This will change the common-mode voltage on the device outputs, because this voltage is derived from half the value on the VCC pin. The device includes an automatic check to figure out which mode the device is in during power up.