Custom MMIC of Chelmsford, Massachusetts, a developer of monolithic microwave integrated circuits (MMICs), has introduced a new product line of GaAs Digital Step Attenuators (DSA). The company intends the DSA family to facilitate the design of high dynamic range receivers and instrumentation. Notably, these applications often must achieve gain control of 50dB or higher. Fine step DSAs (e.g., 0.5dB Least Significant Bit [LSB]) are frequently used for such applications. However, when a large attenuation change is required, Custom MMIC asserts that it is more efficient to use a lower bit count coarse (e.g., 2, 4 or even 8 dB LSB) step DSA MMIC due to a lower insertion loss and fewer control lines for easier design implementation.
Eight New GaAs DSAs
The eight new products now available cover up to 40GHz, with 0.5, 2 and 4dB step size options. Die and QFN packaged versions are available. The CMD281, CMD282, CMD281C3, and CMD282C3 are the company’s initial offerings for coarse control 2 bit DSAs offering 2 and 4 dB step control. The CMD279, CMD280, CMD279C3 and CMD280C3 offer the more traditional 0.5dB step control with a 15.5dB range (5 bit). All of the new devices feature single control line per bit.