ABSTRACT
Before 0.35 µm process technology node (mid-1990), the RFCMOS terminology was not widely recognized in the technical community as it is today. CMOS processing was driven mostly by the needs of digital design and solid-state memories. Something crucial to the popularization of RFCMOS happened around 1997: 0.25 µm CMOS process technology was suddenly accessible to a wide range of designers
✐
✐
✐
✐
✐
✐
✐
with the popularization of silicon foundries. The cut-off frequency of NMOS devices at this node exceeded 25 GHz: this was an important factor as one of the main applications driving integrated RF design was Bluetooth radios which operate at 2.4 GHz. The rule of thumb among many RFCMOS designers is that the cut-off frequency of transistors (fT) in a given technology should be at least ten times the application frequency; it is important to note that there are many exceptions to this guideline, especially in the area of III-V microwave and millimeter-wave applications.
