MB90F334APMC datasheet(16/72 Pages) FUJITSU

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MB90330A Series

DS07-13734-7E

About Crystal oscillator circuit

Noise near the X0/X1 pins and X0A/X1A pins may cause the device to malfunction. Design the printed circuit

board so that X0/X1 pins and X0A/X1A pins, the crystal oscillator (or the ceramic oscillator) and the bypass

capacitor to ground are located as close to the device as possible.

It is strongly recommended to design the PC board artwork with the X0/X1 pins and X0A/X1A pins surrounded

by ground plane because stable operation can be expected with such a layout.

Please ask the crystal maker to evaluate the oscillational characteristics of the crystal and this device.

Caution on Operations during PLL Clock Mode

On this microcontroller, if in case the crystal oscillator breaks off or an external reference clock input stops while

the PLL clock mode is selected, a self-oscillator circuit contained in the PLL may continue its operation at its

self-running frequency. However, Fujitsu will not guarantee results of operations if such failure occurs.

Stabilization of supply voltage

A sudden change in the supply voltage may cause the device to malfunction even within the VCC supply voltage

operating range. For stabilization reference, the supply voltage should be stabilized so that VCC ripple variations

(peak-to-peak value) at commercial frequencies (50 Hz/60 Hz) fall below 10

% of the standard VCC supply voltage

and the transient regulation does not exceed 0.1 V/ms at temporary changes such as power supply switching.

When the dual-supply is used as a single-supply device

If you are using only a single-system of the MB90330A series that come in the dual-system product, use it with

X0A

= VSS : X1A = OPEN.

10. Writing to flash memory

For serial writing to flash memory, always make sure that the operating voltage VCC is between 3.13 V and 3.6 V.

For normal writing to flash memory, always make sure that the operating voltage VCC is between 3.0 V and 3.6 V.

11. Serial communication

There is a possibility to receive wrong data due to noise or other causes on the serial communication. Therefore,

design a printed circuit board so as to avoid noise.

Consider receiving of wrong data when designing the system. For example, apply a checksum to detect an error.

If an error is detected, retransmit the data.

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