AD8325,pdf datasheet (5 V CATV

The differential output pins VOUT+ and VOUT– are also biased to a dc level of approximately VCC/2. Therefore, the outputs should be ac-coupled before being applied to the load. This is accomplished with a 1:1 transformer as seen in the typical applications circuit of Figure 6. The transformer also converts the output signal from differential to single-ended, while maintaining a proper impedance match to the line. The differential output impedance of the AD8325 is internally maintained at 75 W, regardless of whether the amplifier is in transmit enable mode (TXEN = 1) or transmit disable mode (TXEN = 0). If the output signal is being evaluated on standard 50 Wtest equipment, a 75 W to 50 W pad must be used to provide the test circuit with the correct impedance match.