Beyond the boundaries: Enabling new circuit opportunities by using SiGe HBTs in counterintuitive ways

SiGe HBT technology has enjoyed substantial success over the past 25 years for use in realizing performance-constrained, highly-integrated mixed-signal electronics spanning the range of DC to sub-mm-wave operational frequencies. This success has been bolstered by advances in device scaling which have been truly impressive, now routinely achieving multi-hundred GHz frequencies, a fact which is currently opening many new and interesting application possibilities. Most of these emerging opportunities were never envisioned at the very beginning of this field (which is reflective of the inherent nature of innovation), and many involve using the SiGe HBT in ways which may appear counterintuitive to “classical” circuit designers. Examples include operation: in radiation environments, in inverse mode, in weak saturation, and beyond SoA boundaries. This invited paper will explore this emerging design space, both from device and circuit perspectives.