Precision TTL-controlled step attenuators, accurate over 10 to 1000 MHz and -55 to +100°C, are available from Mini-Circuits in hermetically-sealed TO-8 cases and SMA connectorized packages. In each package style, five models are offered, each with three internal discrete attenuators switchable to provide eight discrete and accurate levels up to 35 dB. Models can be cascaded to provide increased attenuation because of the excellent input/output return loss of each model; the final value of attenuation will equal the sum of the attenuations of the individual models. The accuracy of these step attenuators is comparable to precision fixed attenuators. Attenuation values are flat over the full frequency range and the full – 55 to +100°C temperature range.

Three TTL lines are provided, one to correspond with each step of attenuation. To achieve 6-bit attenuation, merely cascade two models. Each step is switched on or off by a TTL signal, with the difference in insertion loss between the on and off state being the step attenuation. The 50Ω TOAT – and ZFAT-series perform with 6 sec switching speed and can handle power levels up to +10 dBm above a few hundred MHz, and 0 dBm at 10 MHz.

For more information on digital step attenuators, see the “Terms and Definitions Article.”

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