S-1111 Datasheet, PDF (16/25 Pages) Seiko Instruments Inc – HIGH RIPPLE-REJECTION LOW DROPOUT

HIGH RIPPLE-REJECTION LOW DROPOUT CMOS VOLTAGE REGULATOR
S-1111/1121 Series
Rev.4.1_00
„ Precautions
• Wiring patterns for the VIN, VOUT and GND pins should be designed so that the impedance is low.
When mounting an output capacitor between the VOUT and VSS pins (C_L) and a capacitor for stabilizing
the input between VIN and VSS pins (C_IN), the distance from the capacitors to these pins should be as
short as possible.
• Note that the output voltage may increase when a series regulator is used at low load current (1.0 mA or
less).
• This IC performs phase compensation by using an internal phase compensator and the ESR of an
output capacitor. Therefore, always place a capacitor of 2.2 μF or more between VOUT and VSS pins.
A tantalum type capacitor is recommended. Moreover, to secure stable operation of the S-1111/1121
Series, it is necessary to employ a capacitor with an ESR within an optimum range (0.5 to 5 Ω). Using a
capacitor whose ESR is outside the optimum range (approximately 0.5 to 5 Ω), whether larger or
smaller, may cause an unstable output, resulting in oscillation. Perform sufficient evaluation under the
actual usage conditions for selection, including evaluation of temperature characteristics.
• The voltage regulator may oscillate when the impedance of the power supply is high and the input
capacitor is small or an input capacitor is not connected.
• The application conditions for the input voltage, output voltage, and load current should not exceed the
package power dissipation.
• Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in
electrostatic protection circuit.
• In determining the output current, attention should be paid to the output current value specified in Table
6 in the electrical characteristics and footnote *5 of the table.
• SII claims no responsibility for any disputes arising out of or in connection with any infringement by
products including this IC of patents owned by a third party.
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Seiko Instruments Inc.