S2D Microwave Inc. offers broad band 0.5 to 20 GHz, high performance 3 Bit, 60 dB switched bit attenuator. S3-AS6055R520 is a high performance compact unit with low insertion loss, fast switching speed, low harmonic distortion, Three-bit attenuation control has TTL driver. Various other attenuator models are also available.
http://www.s2dmicrowave.com/Products_files/products/attenuators/S3-AS6055R520.pdf