Speaker
Mr
Andrew Christie
(Peregrine Semiconductor UK Ltd)
Description
Digital Step Attenuators (DSA’s) are broadly used within Satellite Payloads to adjust signal levels either as standalone blocks or as a key part of complex systems. Wherever a DSA is employed its critical function is delivering accurate, consistent, repeatable level control in a difficult space environment. The environment in space creates additional challenges due to the wide range of temperatures experienced and radiation.
Commercial 7 bit/31.75dB DSA’s have been reported with attenuation errors in the range of (+/-0.1dB + 3% of setting) to (+/-0.15dB + 1.5% of setting) for 8GHz devices. When we investigate these numbers further we find the best attenuation accuracy is typically only achieved over the lower frequency range, typically up to 2GHz. Above these frequencies there are fewer vendors and attenuation accuracy degrades significantly. A 0-13 GHz DSA has been reported with attenuation error of (+/-0.5dB +5% of setting). The attenuation error is highest for the higher attenuation values, to get around this some vendors reduce the maximum attenuation of their DSA’s from 31-32dB to approximately 16dB.
The author will review the building blocks of a DSA and describe circuit and packaging solutions to improve attenuation accuracy as frequency increases.
Measured results for a 6GHz DSA and an 11 GHz DSA will be compared along with the differences in circuit topology and packaging approach. These results will demonstrate how to achieve improved high frequency attenuation error for Microwave DSA’s.
Primary author
Mr
Andrew Christie
(Peregrine Semiconductor UK Ltd)
