RT9816 pdf datasheet (Micro-Po

The RT9816 is a micro-power voltage detector with
deglitched manual reset input supervising the power
supply voltage level for microprocessors (μP) or digital
systems. It provides internally fixed threshold levels with
0.1V per step ranging from 1.0V to 5V, which covers most
digital applications. It features low supply current of 3μA.
The RT9816 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. To pull reset signal
low manually, just pull the manual reset input (MR) below
the specified VIL level. RT9816 is provided in SC-82
package.