1. A device for converting analog to digital, the device comprising: a dual mode converter having a coarse mode and a fine mode, the dual mode converter configured to receive an input signal and convert the input signal to a digital output having a selected resolution; and a control unit coupled to the dual mode converter and configured to operate the converter in the coarse mode until a coarse approximation is obtained and to operate the converter in the fine mode until a fine approximation is obtained having the selected resolution, wherein the fine mode includes multi-bit incremental tracking.