MB90540/540G/545/545G Series
(4) Power On Reset
(MB90F543/F549 : VCC = 5.0 V ± 10%, VSS = AVSS = 0.0 V, TA = −40 °C to +85 °C)
(MB90543G(S)/547G(S)/548G(S)/F548GL(S): VCC = 3.5 V to 5.5 V, VSS = AVSS = 0.0 V, TA = −40 °C to +105 °C)
(Other than MB90F543/F549/543G(S)/547G(S)/548G(S)/F548GL(S):
VCC = 5.0 V ± 10%, VSS = AVSS = 0.0 V, TA = −40 °C to +105 °C)
Value
Pin
Parameter
Symbol
Condition
Units
Remarks
name
Min
0.05
50
Max
Power on rise time
Power off time
tR
VCC
VCC
30
ms
*
tOFF
ms Due to repetitive operation
* : VCC must be kept lower than 0.2 V before power-on.
Note : • The above values are used for creating a power-on reset.
• Some registers in the device are initialized only upon a power-on reset. To initialize these register, turn on
the power supply using the above values.
tR
2.7 V
VCC
0.2 V
0.2 V
0.2 V
tOFF
Sudden changes in the power supply voltage may cause a power-on reset.
To change the power supply voltage while the device is in operation, it is recommended to
raise the voltage smoothly to suppress fluctuations as shown below.
In this case, change the supply voltage with the PLL clock not used. If the voltage drop is
1 V or fewer per second, however, you can use the PLL clock.
VCC
It is recommended to keep the
rising speed of the supply voltage
at 50 mV/ms or slower.
3.0 V
RAM data being held
VSS
47
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