MB89930A Datasheet, PDF (12/42 Pages) Fujitsu Component Limited. – 8-bit Proprietary Microcontroller

MB89930A Series
10. Voltage Step-down Circuit Stabilization Time
MB89930A series contains the following products and the operating characteristics vary with whether they
contain the internal step-down circuit.
Part number
Operating voltage
Voltage step-down circuit
MB89935A
2.2 V to 5.5 V
Not included
MB89935B
2.2 V to 5.5 V
Not included
MB89P935B
3.0 V to 5.5 V
Included
MB89PV930A
2.7 V to 5.5 V
Not included
The same built-in resources are used for the above product types; operating sequences after the power-on reset
are different depending on whether they have the internal voltage step-down circuit.
The operating sequences after the power-on reset with the different models will be described below.
• Operating sequences after the power-on reset with the different models
Power supply (VCC)
CPU operation of the product
having the internal voltage
step-down circuit
(MB89P935B)
CPU operation of the product
not having the internal voltage
step-down circuit (MB89935A/
935B, MB89PV930A)
Voltage step-down
oscillation
circuit stabilization + _{stabilization time}
time (2¹⁷/FCH*)
(2¹⁸/FCH*)
oscillation
stabilization time
(2¹⁸/FCH*)
Start of CPU operation for the product
not having the internal voltage step-
down circuit (reset vector)
Start of CPU operation for the product
not having the internal voltage step-
down circuit (reset vector)
* : FCH : Crystal oscillator frequency
As described above, CPU starts at delayed time with the product having the internal voltage step-down circuit
compared with the product not having the internal voltage step-down circuit. This is because the time should be
allowed for the stabilization time for voltage step-down circuit for normal operation.
11. If used exceeding Ta = +85 °C, be sure to contact us for reliability limitations.
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