S-77100 Datasheet, PDF (26/40 Pages) Seiko Instruments Inc – POWER SEQUENCER

POWER SEQUENCER
S-77100/77101 Series
Rev.1.0_01
 Power-on
When the power supply is raised, the S-77100/77101 Series performs initialization due to the power-on reset circuit. If
initialization is not performed normally, a malfunction may occur. In order to operate the power-on reset circuit
normally, raise the power supply with the following method.
1. Power supply raising method
As shown in Figure 29, start to raise the power supply from 0.2 V or lower. Moreover, the time the voltage reaches
to the operation power supply voltage min. should be within 10 ms.
Within 10 ms
2.2 V
(Operation power
supply voltage min.)
0.2 V or lower
0 V ^*1
tINIT ^*2
*1. 0 V indicates that there is no potential difference between the VDD pin and the VSS pin of the S-77100/77101
Series.
*2. Initialization time (tINIT) indicates the time that the S-77100/77101 Series performs the initialization internally.
During this duration, the S-77100/77101 Series does not accept the input. Refer to "2. Initialization time" for
the details.
Figure 29
If initialization is completed normally due to the power-on reset circuit, the S-77100/77101 Series becomes off
period when the ON pin is "L", and on-sequence period when the ON pin is "H". When the operation conditions of
the power-on reset circuit are not satisfied, a malfunction may occur since the S-77100/77101 Series cannot
perform initialization. When the operation is unstable, raise the power supply voltage again so as to satisfy the
condition of Figure 29 after lowering the power supply voltage to the VSS level.
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