S-814 Datasheet, PDF (14/32 Pages) Seiko Instruments Inc – LOW DROPOUT CMOS VOLTAGE REGULATOR

LOW DROPOUT CMOS VOLTAGE REGULATOR
S-814 Series
Rev.2.1_00
„ Selection of Output Capacitor (C_L)
Mount an output capacitor between VOUT pin and VSS pin for phase compensation. The S-814 Series
enables customers to use a ceramic capacitor as well as a tantalum or an aluminum electrolytic capacitor.
• A ceramic capacitor or an OS capacitor:
Use a capacitor of 0.47 μF or more.
• A tantalum or an aluminum electrolytic capacitor:
Use a capacitor of 0.47 μF or more and ESR of 10 Ω or less.
Pay special attention not to cause an oscillation due to an increase in ESR at low temperatures, when
you use the aluminum electrolytic capacitor. Evaluate the capacitor taking into consideration its
performance including temperature characteristics.
Overshoot and undershoot characteristics differ depending upon the type of the output capacitor you
select. Refer to “C_L dependencies of overshoot” and “C_L dependencies of undershoot” in
“„ Transient Response Characteristics”.
„ Precautions
• Wiring patterns for VIN pin, VOUT pin and GND pin should be designed so that the impedance is low.
When mounting an output capacitor, the distance from the capacitor to the VOUT pin and the VSS pin
should be as short as possible.
• Note that output voltage may increase when a series regulator is used at low load current (Less than 10
μA).
• Generally, a series regulator may cause oscillation, depending on the selection of external parts. The
following conditions are recommended for this IC. However, be sure to perform sufficient evaluation under
the actual usage conditions to select the series regulator.
Output capacitor (C_L):
0.47 μF or more
Equivalent Series Resistance (ESR): 10 Ω or less
Input series resistance (R_IN):
10 Ω or less
• 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 input voltage and load current do not exceed the power dissipation level of
the package.
• In determining the output current, attention should be paid to the output current value specified and
footnote *3 in Table 5 in the “„ Electrical Characteristics”.
• Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in
electrostatic protection circuit.
• SII claims no responsibility for any and all 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.