MB91F248 Ver la hoja de datos (PDF) - Fujitsu

Número de pieza

componentes Descripción

Fabricante

MB91F248

32-bit Microcontroller

Fujitsu 

MB91245/S Series

■ HANDLING DEVICES

• Preventing Latch-up

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

output pin, or if an above-rating voltage is applied between VCC pin and VSS pin. 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 an unused input pin open, since it 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.

• About 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 external power supply and a ground line 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 with the VCC and VSS pins of this device at the low impedance.

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

pin and VSS pin near this device.

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

the VCC pin and always connect a 1 μF or greater capacitor to the VCC3C pin for the regulator.

• Example of power supply connection

5V

5V

GND

VCC

AVCC

AVRH

AVSS

VSS

VCC3C

1 μF

16

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