The AD8367 is a high-performance 45 dB variable gain amplifier with linear-in-dB gain control for use from low frequencies up to several hundred megahertz. The range, flatness, and accuracy of the gain response are achieved using Analog Devices' X-AMP architecture, the most recent in a series of powerful proprietary concepts for variable gain applications, which far surpasses what can be achieved using competing techniques. The input is applied to a 200 resistive ladder network, having nine sections each of 5 dB loss, for a total attenuation of 45 dB. At maximum gain, the first tap is selected; at progressively lower gains, the tap moves smoothly and continuously toward higher attenuation values. The attenuator is followed by a 42.5 dB fixed gain feedback amplifier--essentially an operational amplifier with a gain bandwidth product of 100 GHz--and is very linear, even at high frequencies. The output third order intercept is +20 dBV at 100 MHz (+27 dBm re 200 ), measured at an output level of 1 V p-p with VS = 5 V.