The Silicon Creations 3-Supply Power-On Reset circuit provides a fixed width reset pulse for chip initialization after power up. The design senses the voltage level of three supply domains (0.9V, 1.8V, and optionally 3.3V) and initiates the reset pulse when all three supplies are above 80% of the nominal value. The POR includes a built-in bandgap voltage reference circuit and is designed to be insensitive to supply ramp times. Brown-out protection is also included.