S1335 datasheet(33/67 Pages) SII

33 / 67 page

HIGH RIPPLE-REJECTION SOFT-START FUNCTION CMOS VOLTAGE REGULATOR

Rev.1.3_00

S-1335 Series

Seiko Instruments Inc.

4. Discharge shunt function (S-1335 Series A / B / E / F / J / K type)

The S-1335 Series A / B / E / F / J / K 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 VSS 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-1335 Series C / D / G / H / L / M type does not have a discharge shunt circuit, the VOUT pin is set to the

VSS level through several hundred k

Ω internal divided resistors between the VOUT pin and the VSS pin. The S-1335

Series A / B / E / F / J / K type allows the VOUT pin to reach the VSS level rapidly due to the discharge shunt circuit.

Output transistor: OFF

ON / OFF pin: OFF

VIN

ON / OFF

VSS

ON / OFF circuit

Discharge shunt circuit

: ON

VOUT

*1. Parasitic diode

Current flow

GND

S-1335 Series A / B / E / F / J / K type

Output

capacitor

(CL)

Figure 29

5. Pull-down resistor (S-1335 Series A / C / E / G / J / L 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 VSS

level.

Note that the IC’s current consumption increases as much as current flows into the pull-down resistor of 2.2 M

Ω typ.

when the ON / OFF pin is connected to the VIN pin.

S1335 Datasheet(PDF) 33 Page - Seiko Instruments Inc