µ
PD78C14(A)
51
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.
Environmental 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 device 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 V
DD
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.
MS-DOS is a trademark of Microsoft Corporation.
PC/AT and PC DOS are trademarks of IBM Corporation.
*
