MB91220/S データシートの表示（PDF） - Fujitsu

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コンポーネント説明

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MB91220/S

32-bit Microcontroller

Fujitsu 

MB91220/S Series

■ HANDLING DEVICES

• Preventing Latch-up

Latch-up may occur in a CMOS IC, if a voltage greater than VCC or less than VSS is applied to input and output

pin, or if an above-rating voltage is applied between VCC and VSS pins. When latch-up occurs, it may significantly

increase the power supply current, and may cause thermal destruction of an element. When you use a CMOS

IC, be very careful not to exceed the maximum rating.

• Treatment of Unused Input Pins

Do not leave unused input pins open, as this may cause a malfunction. Handle by performing a pull-up or pull-

down with a resistance of 2 kΩ or more. An unused I/O pin should be set to the output status and left open.

When set to the input status, it should be handled in the same way as an input pin.

• Power supply pins

If there are multiple VCC and VSS pins, from the point of view of device design pins to be of the same potential

are connected inside the device to prevent such malfunctioning as latch-up. However, you must connect all the

pins to the external power supply and ground lines to lower the electro-magnetic emission level, to prevent

abnormal operation of strobe signals caused by the rise in the ground level, and to conform to the total output

current rating. Moreover, connect the current supply source to the VCC and VSS pins of this device via a low

impedance.

Furthermore, it is also advisable to connect a ceramic bypass capacitor of approximately 0.1 µF between VCC

and VSS near this device.

This device incorporates a regulator. When using the device with 5 V power supply, apply that power supply to

the VCC pin and always connect the VCC3C pin to a capacitor with 1 µF or more for the purpose of regulator.

• Example of power supply connection

5V

5V

5V

GND

VCC

DVCC

AVCC

AVRH

AVSS

VSS

DVSS

VCC3C

1 µF

20

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