The Overview
Mini-Circuits’ ZX76-50G-30-V+ digital step attenuator (DSA) is a 50-Ω device that delivers adjustable attenuation from 0 to 31.5 dB in 0.5-dB steps.
Who Needs It & Why?
The ZX76-50G-30-V+ DSA has multiple applications in communications, satcom, and defense test setups. Use cases include 5G; X-band, S-band, C-band, Ku-band, and K-band radars; and electronic-warfare test sets.
Under the Hood
With operation specified from 100 MHz to 50 GHz, the ZX76-50G-30-V+ can function at frequencies up to 55 GHz. It’s controlled through a 6-bit parallel interface with a single positive supply voltage of +2.3 to +5.5 V (+3.3 V nominal). The six control bits select the desired attenuation state (see figure). Thanks to its VSWR of just 1.5:1 (typical), the unit is easy to interface with adjacent components and provides low-amplitude ripple.
A novel architecture reduces RF output-power spikes during attenuation to 0.3 dB (typical), which reduces system noise and eliminates risk of a transient spike that could damage sensitive components. In addition, the use of a single positive supply simplifies power-supply design. An internal negative-voltage generator supplies the desired negative voltage.
The single positive supply results in excellent spurious performance. In applications that require the lowest possible spurious performance, a negative voltage can be applied externally to bypass the internal negative-voltage generator.
Equipped with 2.4-mm coaxial connectors, the ZX76-50G-30-V+ comes packaged in a unibody case, which provides ruggedness and the ability to withstand severe environments.