A 366mW direct digital synthesizer at 15GHz clock frequency in SiGe Bipolar technology

A direct digital synthesizer (DDS) with 6-bit amplitude and 8-bit phase resolution is presented. The phase-to-amplitude mapping circuit is implemented as a differential pair in saturation. The suitability of this circuit for broadband application and high temperature range is shown. The use of a modern SiGe bipolar technology enables both a low power consumption of 366 mW and a high clock frequency of 15 GHz. A spurious free dynamic range (SFDR) between 42 and 20 dBc is achieved. The chip is fabricated in a 0.35 mum 200-GHz f
_T
SiGe bipolar technology and occupies only 1024 times 1128 mum
²
.