For Consumer / IoT
Voltage Detectors (Reset ICs)Function
A SENSE pin is one used only for voltage monitoring.
In general, the VDD pin on reset ICs also functions as a voltage detection pin (SENSE pin).
Some reset ICs, however, have a SENSE pin separated from the VDD pin.
If the VDD input is lower than the minimum operating voltage, reset ICs with a VDD-cum-SENSE pin may become unstable and fail to keep a reset signal.
As illustrated below, the reset signal by CMOS output becomes unstable, and the one by Nch open drain is equal to the pull-up voltage.
On the other hand, reset ICs with a separated SENSE pin can keep a reset signal even when the VDD input is below the minimum operating voltage, as long as a voltage is applied to the VDD pin.
A manual reset pin (MR pin) is one to forcibly reset the voltage detector (reset IC).