The invention provides an ultra-
wide band low-
noise single-ended input and differential output
amplifier, which is characterized in that the
amplifier comprises a common-gage amplification stage (1), a single-ended-to-differential stage (2) and a
capacitor cross-
coupling output buffer (3), wherein an output end of the common-gate amplification stage (1) is connected with an input end of the single-ended-to-differential stage (2); and an output end of the single-ended-to-differential stage (2) is connected with an input end of the
capacitor cross-
coupling output buffer (3). According to
amplifier, a pre-amplification stage and the single-ended-to-differential stage adopt a current reuse technology, so that
one stage of
current consumption can generate two stages of amplification; the common-gate amplification stage provides
wide band input matching and avoids a no-source matching network; load impedances of the pre-amplification stage and the single-ended-to-differential stage are resonated at different frequencies respectively; functions of
signal amplification of the
wide band and single-ended-to-differential are realized by
gain complementation of the pre-amplification stage and the single-ended-to-differential stage; a
capacitor cross-
coupling technology is applied in the output buffer additionally; amplitude and phase of an output differential
signal are compensated to reach the balance between the amplitude and the phase of the differential
signal; and the
gain of the output buffer is increased.