APN2014

APPLICATION NOTE APN2014: 6 Bit 63 dB RF Digital Attenuator Solution 500–2000 MHz High dynamic range systems often require an attenuator with a very wide attenuation range. It is possible to achieve 63 dB attenuation range by cascading two low cost digital attenuators, AA101-80 and AA104-73. It is effectively impossible to achieve such high attenuation range with a single package device. AA101-80 is a 5-bit attenuator with a 1 dB least significant bit (LSB). Full-scale attenuation for this attenuator is 31 dB. AA104-73 is a 1-bit digital attenuator that produces 32 dB attenuation. When these two attenuators are cascaded on a standard FR4 printed circuit board, 63 dB total attenuation range with 1 dB step size is produced within the frequency range 500 MHz to 2 GHz. VS V1 V5 R1 AA101-80 C1 V6 V7 AA104-73 C2 C3 R1: 10 kΩ C1, C3: 47 pF C2: 12 pF Figure 1. Block Diagram, 6 Bit Attenuator, 900 MHz The AA104-73 offers unique design flexibility in a miniature SOT-6 package. This ...