UPD753108 Datasheet, PDF (3/459 Pages) NEC – 4-bit Single-chip Microcontrollers

NOTES FOR CMOS DEVICES
1 PRECAUTION AGAINST ESD FOR SEMICONDUCTORS
Note:
Strong electric field, when exposed to a MOS device, can cause destruction of the gate oxide
and ultimately degrade the device operation. Steps must be taken to stop generation of static
electricity as much as possible, and quickly dissipate it once, when it has occurred. Environ-
mental control must be adequate. When it is dry, humidifier should be used. It is recommended
to avoid using insulators that easily build static electricity. Semiconductor devices must be
stored and transported in an anti-static container, static shielding bag or conductive material.
All test and measurement tools including work bench and floor should be grounded. The
operator should be grounded using wrist strap. Semiconductor devices must not be touched
with bare hands. Similar precautions need to be taken for PW boards with semiconductor
devices on it.
2 HANDLING OF UNUSED INPUT PINS FOR CMOS
Note:
No connection for CMOS device inputs can be 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. All handling related to the unused pins must be
judged device by device and related specifications governing the devices.
3 STATUS BEFORE INITIALIZATION OF MOS DEVICES
Note:
Power-on does not necessarily define initial status of MOS device. Production process of MOS
does not define the initial operation status of the device. Immediately after the power source
is turned ON, the devices with reset function have not yet been initialized. Hence, power-on
does not guarantee out-pin levels, I/O settings or contents of registers. Device is not initialized
until the reset signal is received. Reset operation must be executed immediately after power-
on for devices having reset function.
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