FAQ: Logic and Voltage Translation > Monostable Multivibrators >> Current FAQ
Unused channels for a logic monostable multivibrator (MMV) such as the SN74LV221A should be terminated such that:
(1) All inputs are at a valid logic level (Vcc or GND)
(2) CLR is GND
(3) Rext/Cext is Vcc (this can be a pull-up resistor to Vcc)
(4) Cext is GND (optionally this can be left floating, but we recommend connecting to ground)
You may also like to read the FAQ on how an MMV works, located here: https://e2e.ti.com/support/logic/f/151/t/863529