For R55x0/R57x0 products, which attenuation setting to use will depend on the signal strength the device will receive.

  • In general for any signal under ~ -25 dBm, 0 dB attenuation could be used and is recommended.
  • When expecting a strong signal at ~ -25 dBm or higher, increase the attenuation level (i.e. don't use 0 dB attenuation) to prevent potential input signals reaching the saturation point.
  • When expecting a¬†weak signal, at - 60 dBm or lower, use 0 dB attenuation. ¬†Without attenuation, the dynamic range increases as the noise floor drops making more visible the weak signals.

If you have a 418 or 427 model, have a look at the Gain/Attenuation Settings application note.