This macro-cell is a general purpose, ultra low power internal oscillator core designed for SilTerra 0.18μm CL180G CMOS technology.
The circuit has internal level shifting. A 4-bit digital bus allows frequency calibration against process variations. It requires an external 15.5nA current bias (sink), which can be implemented with CM1014ff IP.
The core is easily retargeted to any other CMOS technology due to its MOSFET-only oscillator architecture.
