S-8821 Datasheet, PDF (10/19 Pages) Seiko Instruments Inc – VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER

VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER
S-8821 Series
Rev.3.1_00
3. Shutdown Pin (ON/OFF Pin)
Setting the ON/OFF pin to the Low level ("L") causes the voltage of the VOUT pin to change to the GND
level and simultaneously the operation of all the internal circuit to stop. At this time, the consumption
current is largely reduced, to a level of approximately 0.3 μA.
The structure of the ON/OFF pin is as shown in Figure 9. Since the ON/OFF pin is neither pulled down
nor pulled up internally, do not use it in the floating state.
When the ON/OFF pin is not used, connect it to the VIN pin.
Table 5
ON/OFF pin
“H”: Power on
“L”: Power off
Internal circuit
Operating
Stop
VOUT pin voltage
Set value
V_GND level
VIN
VIN
ON/OFF
GND
Figure 9
4. Soft Start Function
The S-8821 Series features a built-in soft start circuit. Upon power application or when the ON/OFF pin
is switched from "L" to "H", the output voltage gradually rises over the soft start time, and the output
current is gradually output as a result. This soft start function reduces the input current rush.
10
Seiko Instruments Inc.