A two-bit offset canceling A/D converter with improved common mode
rejection and threshold sensitivity for use in GPS receivers. A device in
accordance with the present invention comprises a level shifter, the
level shifter receiving a positive signal and a negative signal, the
level shifter shifting the positive signal and the negative signal such
that a difference between the positive signal and the negative signal is
larger than a threshold value, and a comparator, coupled to the level
shifter, the comparator providing as outputs of the comparators a sign
bit and two magnitude bits wherein the comparator comprises a plurality
of switched capacitor amplifiers.