How should address pins and other unused pins be handled during design?
Fix the input level of unused pins either to high or low level. No connection for CMOS devices input pins can be a cause of malfunction. If no connection is provided to the input pins, it is possible that an internal input level may be generated due to noise, etc., hence causing malfunction. CMOS devices behave differently than Bipolar or NMOS devices. Input levels of CMOS devices must be fixed high or low by using a pull-up or pull-down circuitry. Each unused pin should be connected to VDD or GND with a resistor, if it is considered to have a possibility of being an output pin. For products whose data sheet contains a “Handling of Unused Pins”, be sure to observe the described directions.
