The RT9819 is a micro-power voltage detector supervising the power supply voltage level for microprocessors (P) or digital systems. It provides internally fixed threshold levels with 0.1V per step ranging from 1.2V to 5V, which covers most digital applications. It features low supply current of 3A. The RT9819 performs supervisory function by sending out a reset signal whenever the VDD voltage falls below a preset threshold level. This reset signal will last the whole period before VDD recovering. Once VDD recovered upcrossing the threshold level, the reset signal will be released after a certain delay time. RT9819 is provided in SC-70-3, SC-82 and SOT-23-3 packages.