HIGH RIPPLE-REJECTION LOW DROPOUT MIDDLE OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.3.2_00
S-1132 Series
3. Shutdown pin (ON/OFF pin)
This pin starts and stops the regulator.
When the ON/OFF pin is set to the shutdown level, the operation of all internal circuits stops, and the built-in P-channel
MOS FET output transistor between the VIN pin and VOUT pin is turned off to substantially reduce the current
consumption. The VOUT pin becomes the VSS level due to the internally divided resistance of several hundreds kΩ
between the VOUT pin and VSS pin.
The structure of the ON/OFF pin is as shown in Figure 14. Since the ON/OFF pin is neither pulled down nor pulled up
internally, do not use it in the floating state. In addition, note that the current consumption increases if a voltage of 0.3
V to VIN – 0.3 V is applied to the ON/OFF pin. When the ON/OFF pin is not used, connect it to the VSS pin if the logic
type is “A” and to the VIN pin if it is “B”.
Table 7
Logic Type
ON/OFF Pin
“L”: Power on
“H”: Power off
“L”: Power off
“H”: Power on
Internal Circuits
Operating
Stopped
VOUT Pin Voltage
Set value
Current Consumption
A
A
B
B
ISS1
ISS2
ISS2
ISS1
VSS level
Stopped
VSS level
Operating
Set value
VIN
ON/OFF
VSS
Figure 14
14
Seiko Instruments Inc.
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