Optimized Ring Oscillator With 1.65-ps Gate Delay in a SiGe:C HBT Technology

In this letter, we report a record gate delay of 1.65 ps of a current-mode logic ring oscillator (RO) fabricated with an advanced SiGe:C heterojunction bipolar transistor technology. Outstanding performance has been achieved through process and layout optimization and inductive peaking in series with the load resistor. The RO operates at a single-ended voltage swing of 200 mV. The transistors used in the RO exhibit a peak transit frequency f
_T
of 310 GHz and a peak maximum oscillation frequency f
_max
of 400 GHz. To the best of our knowledge, a gate delay of 1.65 ps is the fastest result for a bipolar transistor-based technology.