The SSM2143 is an integrated differential amplifier intended to receive balanced line inputs in audio applications requiring a high level of immunity from common-mode noise. The device provides a typical 90 dB of common-mode rejection (CMR), which is achieved by laser trimming of resistances to better than 0.005%. Additional features of the device include a slew rate of 10 V/µs and wide bandwidth. Total harmonic distortion (THD) is less than 0.004% over the full audio band, even while driving low impedance loads. The SSM2143 input stage is designed to handle input signals as large as +28 dBu at G = 1/2. Although primarily intended for G = 1/2 applications, a gain of 2 can be realized by reversing the +IN/-IN and SENSE/REFERENCE connections. When configured for a gain of 1/2, the SSM2143 and SSM2142 Balanced Line Driver provide a fully integrated, unity gain solution to driving audio signals over long cable runs. For similar performance with G = 1, see SSM2141.