mb90f378 Fujitsu Microelectronics, Inc., mb90f378 Datasheet - Page 47

• Manufacturer Part Number: mb90f378
• Description: 16-bit Proprietary Microcontroller
• Manufacturer: Fujitsu Microelectronics, Inc.

* : V
Notes : • The above values are used for causing a power-on reset.
(3) Power-on Reset
Power supply rise time
Power supply cut-off time
CC
1.8 V
V
V
V
must be kept lower than 0.2 V before power-on.
CC
CC
SS
Parameter
• Make sure that power supply rises within the selected oscillation stabilization time. If the power supply
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.
Some registers in the device are initialized only upon a power-on reset. To initialize these registers, turn
on the power supply using the above values.
voltage needs to be varied in the course of operation, a smooth voltage rise is recommended.
0.2 V
(V
Symbol Pin name Condition
CC
t
OFF
t
R
= 2.7 V to 3.6 V, AV
2.2 V
t
R
V
V
RAM data hold
CC
CC
*
*
CC
⎯
= 2.7 V to 3.6 V, V
0.2 V
Min
⎯
1
Value
t
OFF
SS
Max
= AV
50
⎯
MB90378 Series
It is recommended to keep the
rising speed of the supply voltage
at 50 mV/ms or slower.
SS
= 0.0 V, T
0.2 V
Unit
ms
ms
Due to repeated
operations
A
= −40 °C to +85 °C)
Remarks
47