DSAs

A digital step attenuator (DSA) is a programmable RF attenuator built from cascaded switched attenuator cells, each contributing a binary-weighted attenuation step. The result is a single component that can be set to any attenuation value across its range in fixed increments — typically 0.25, 0.5, or 1 dB — via a serial bus or parallel control lines. DSAs replace the older, more complex approach of cascading discrete fixed pads with relays or PIN-diode networks, and they do it with monotonic, repeatable, fast switching across the entire band.

Selection of a DSA comes down to attenuation range (how many dB total can the part absorb), step size (the resolution of each digital code), insertion loss at the 0 dB reference state, frequency range, and linearity under expected RF power levels. Modern DSAs also offer SPI control with addressable devices on a shared bus and pre-loaded state-switching pins for rapid hop sequences in radar / EW / TDD applications.

Typical applications include automatic gain control (AGC) loops in cellular and SatCom radios, transmit-power leveling, calibration paths in test instrumentation, beamforming amplitude tapering, and TDD radio architectures that need fast attenuation transitions between transmit and receive states.

The table below lists the active DSA portfolio sorted by SKU, with frequency range, attenuation range, step size, insertion loss, and package. Click any SKU for the full data sheet, S-parameters, and reference designs.