The AD8320 is made up of a digitally controlled variable attenuator of 0 dB to 36 dB, which is preceded by a low noise, fixed gain buffer and followed by a low distortion high power amplifier. The AD8320 has a 220 input impedance and accepts a single-ended input signal with a specified analog input level of up to 0.310 V p-p. The output is specified for driving a 75 load, such as coaxial cable, although the AD8320 is capable of driving other loads. Distortion performance of 57 dBc is achieved with an output level up to 12 dBm (3.1 V p-p) at 42 MHz, while 46 dBc distortion is achieved with an output level up to 18 dBm (6.2 V p-p). A key performance and cost advantage of the AD8320 results from the ability to maintain a constant 75 output impedance during power-up and power-down conditions. This eliminates the need for external 75 back-termination, resulting in twice the effective output voltage when compared to a standard operational amplifier. Additionally, the on-chip 75 termination