MB89P147 datasheet(11/38 Pages) FUJITSU

11 / 38 page

MB89143A/144A

s HANDLING DEVICES

1. Preventing Latchup

Latchup may occur on CMOS ICs if voltage higher than VCC or lower than VSS is applied to input and output pins

other than medium- to high-voltage pins or if higher than the voltage which shows on “1. Absolute Maximum

Ratings” in section “s Electrical Characteristics” is applied between VCC and VSS. (However, up to 7.0 V can be

applied to P31/INT1 pin, regardless of VCC.)

When latchup occurs, power supply current increases rapidly and might thermally damage elements. When

using, take great care not to exceed the absolute maximum ratings.

Also, take care to prevent the analog power supply (AVR) and analog input from exceeding the digital power

supply (VCC) when the analog system power supply is turned on and off.

2. Treatment of Unused Input Pins

Leaving unused input pins open could cause malfunctions. They should be connected to a pull-up or pull-down

resistor.

3. Treatment of Power Supply Pins on Microcontrollers with A/D and D/A Converters

Connect to be AVSS = AVR = VSS even if the A/D and D/A converters are not in use.

4. Treatment of N.C. Pins

Be sure to leave (internally connected) N.C. pins open.

5. Power Supply Voltage Fluctuations

Although VCC power supply voltage is assured to operate within the rated range, a rapid fluctuation of the voltage

could cause malfunctions, even if it occurs within the rated range. Stabilizing voltage supplied to the IC is

therefore important. As stabilization guidelines, it is recommended to control power so that VCC ripple fluctuations

(P-P value) will be less than 10% of the standard VCC value at the commercial frequency(50 to 60 Hz) and the

transient fluctuation rate will be less than 0.1 V/ms at the time of a momentary fluctuation such as when power

is switched.

6. Precautions when Using an External Clock

Even when an external clock is used, oscillation stabilization time is required for power-on reset and wake-up

from stop mode.

MB89P147 데이터시트(PDF) 11 Page - fujitsu semiconductor