This macro-cell is a general purpose, low power, 4MHz internal oscillator core designed for TowerJazz TS18SL 0.18µm CMOS technology. Two other oscillator outputs are available: 2MHz and 500kHz. A 4-bit digital bus allows frequency calibration against process variations. It includes a start-up circuit and an internal 17nA current bias that is also available in two output pins (200nA) after mirroring. Alternatively, an external 135nA current bias can be used. The core is ideal for applications where power consumption is critical.