UPD780921 datasheet(38/40 Pages) RENESAS

38 / 40 page

µPD780921, 780922, 780923, 780924

NOTES FOR CMOS DEVICES

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.

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 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.

STATUS BEFORE INITIALIZATION OF MOS DEVICES

Note: Power-on does not necessarily define initial status of MOS device. Produc-

tion 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 imme-

diately after power-on for devices having reset function.

UPD780921 데이터시트(PDF) 38 Page - Renesas Technology Corp