The tinytapeout-to-radio-chip path now exists

Article excerpt

A university team designed the frequency-synthesizer core of a WiFi/BLE-class radio (a full 2.4 GHz fractional-N PLL) on IHP’s open 130nm BiCMOS process using a 100% open-source EDA flow, no proprietary tools anywhere. The hard part was always the passives: nobody trusted open models for on-chip spiral inductors, so open silicon stuck to digital. They modeled a custom 4 nH inductor (Q of 16.8 at 2.45 GHz) in OpenEMS and it worked, phase noise of -100.8 dBc/Hz at 1 MHz offset, 0.62 mm², 12.7 mW. That’s respectable, not toy-grade. See the paper documenting the inductor fabrication on arxiv. See more about tinytapeout.