S-19244A12A-E8T1U Datasheet, PDF (28/68 Pages) Seiko Instruments Inc – CMOS VOLTAGE REGULATOR WITH SOFT-START FUNCTION

FOR AUTOMOTIVE 125°C OPERATION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR WITH SOFT-START FUNCTION
S-19244xxxA Series
Rev.3.0_00
4. Discharge shunt function (S-19244xxxA Series A / B / E / F type)
The S-19244xxxA Series A / B / E / F 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-19244xxxA Series C / D / G / H 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-19244xxxA Series A / B / E / F type allows the VOUT pin to reach the V_SS level rapidly due to the discharge shunt
circuit.
S-19244xxxA Series
Output transistor: OFF
*1
VIN
VOUT
ON / OFF
ON / OFF circuit
ON / OFF pin: OFF
Discharge shunt circuit
: ON
*1
Current flow
Output
capacitor
(C_L)
VSS
GND
*1. Parasitic diode
Figure 31
5. Pull-down resistor (S-19244xxxA Series A / C / E / G 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
4.0 MΩ typ. when the ON / OFF pin is connected to the VIN pin.
28