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MB90335 Series
●
Note on using external clock
If you are using the external clock, you must connect external pins as shown in the Figure 1.7-1.
Figure 1.7-1 illustrates an external clock usage. (under f=7 MHz)
●
Stabilization of supply power supply
A sudden change in the power supply may cause the device to malfunction even within the V
supply voltage operating range. As stabilization guidelines, it is recommended to voltage fluctuations so
control that V
commercial frequency (50 or 60 MHz) and the transient fluctuation rate does not exceed 0.1 V/ms at power-
on/off etc.
●
Crystal oscillator circuit of low voltage use
If you are using the device with voltages of 2.0 V or less, the external crystal oscillator may not oscillate at
power-on. Therefore, It will recommend the use of the external clock.
●
Writing to flash memory
For serial writing to flash memory, always make sure that the operating voltage V
3.6 V.
For normal writing to flash memory, always make sure that the operating voltage V
3.6 V.
●
Note on PLL clock mode operation
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 Microelectronics will not guarantee results of
operations if such failure occurs.
CM44-10137-6E
Figure 1.7-1 Method for Using External Clock
ripple fluctuations (P-P value) do not exceed 10% of the standard V
CC
FUJITSU MICROELECTRONICS LIMITED
X0
OPEN
X1
CHAPTER 1 OVERVIEW
1.7 Handling of Device
power
CC
value at the
CC
is between 3.13 V and
CC
is between 3.0 V and
CC
17
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