S-13A1 Datasheet, PDF (31/74 Pages) Seiko Instruments Inc – HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR

HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.1_00
S-13A1 Series
4. Discharge shunt function (S-13A1 Series A / B type)
The S-13A1 Series A / B type has a built-in discharge shunt circuit to discharge the output capacitance. The output
capacitance is discharged as follows so that the VOUT pin reaches the V_SS level.
(1) The ON / OFF pin is set to OFF level.
(2) The output transistor is turned off.
(3) The discharge shunt circuit is turned on.
(4) The output capacitor discharges.
Since the S-13A1 Series C / D type does not have a discharge shunt circuit, the VOUT pin is set to the V_SS level
through several hundred kΩ internal divided resistors between the VOUT pin and the VSS pin. The S-13A1 Series A /
B type allows the VOUT pin to reach the V_SS level rapidly due to the discharge shunt circuit.
Output transistor: OFF
*1
VIN
S-13A1 Series
VOUT
ON / OFF
ON / OFF circuit
ON / OFF pin: OFF
Discharge shunt circuit
: ON
*1
Current flow
Output
capacitor
(C_L)
VSS
*1. Parasitic diode
Figure 32
GND
5. Pull-down resistor (S-13A1 Series A / C type)
The ON / OFF pin is internally pulled down to the VSS pin in the floating status, so the VOUT pin is set to the V_SS
level.
Note that the IC's current consumption increases as much as current flows into the pull-down resistor of 2.5 MΩ typ.
when the ON / OFF pin is connected to the VIN pin and the S-13A1 Series A / C type is operating.
31