
MB90580C Series
DS07-13710-6E
87
(4) Power-on Reset
(VCC
= 5.0 V±10%, VSS = AVSS = 0.0 V, TA = 40 °C to +85 °C)
* : VCC must be kept lower than 0.2 V before power-on.
Note: The above values are used for causing a power-on reset.
If HST = “L”, be sure to turn the power supply on using the above values to cause a power-on reset whether
or not the power-on reset is required.
Some registers in the device are initialized only upon a power-on reset. To initialize these registers, turn the
power supply using the above values.
Parameter
Symbol Pin name Condition
Value
Unit
Remarks
Min
Max
Power supply rising time
tR
VCC
0.05
30
ms
Power supply cut-off time
tOFF
VCC
4
ms
Due to repeated
operations
VCC
VSS
3.0 V
tR
tOFF
2.7 V
0.2 V
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 recom-
mended 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 volt-
age drop is 1 V or fewer per second, however, you can use the PLL clock.
It is recommended to keep the
rising speed of the supply voltage
at 50 mV/ms or slower.
RAM data hold