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S-19243A12A-E8T1U Datasheet, PDF (25/74 Pages) Seiko Instruments Inc – CMOS VOLTAGE REGULATOR WITH SOFT-START FUNCTION
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FOR AUTOMOTIVE 125°C OPERATION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR WITH SOFT-START FUNCTION
Rev.3.0_00
S-19243xxxA Series
 Condition of Application
Input capacitor (CIN): A ceramic capacitor with capacitance of 2.2 μF or more is recommended.
Output capacitor (CL): A ceramic capacitor with capacitance of 2.2 μF or more is recommended.
Caution Generally, in a voltage regulator, an oscillation may occur depending on the selection of the external
parts. Perform thorough evaluation including the temperature characteristics with an actual
application using the above capacitors to confirm no oscillation occurs.
 Selection of Input Capacitor (CIN) and Output Capacitor (CL)
The S-19243xxxA Series requires CL between the VOUT pin and the VSS pin for phase compensation. The operation
is stabilized by a ceramic capacitor with capacitance of 2.2 μF or more. When using an OS capacitor, a tantalum
capacitor or an aluminum electrolytic capacitor, the capacitance also must be 2.2 μF or more. However, an oscillation
may occur depending on the equivalent series resistance (ESR).
Moreover, the S-19243xxxA Series requires CIN between the VIN pin and the VSS pin for a stable operation.
Generally, an oscillaiton may occur when a voltage regulator is used under the conditon that the impedance of the
power supply is high.
Note that the output voltage transient characteristics varies depending on the capacitance of CIN and CL and the value
of ESR.
Caution Perform thorough evaluation including the temperature characteristics with an actual application to
select CIN and CL.
 Selection of Capacitor for Soft-start (CSS)
The S-19243xxxA Series E / F / G / H type requires the capacitor for soft-start (CSS) between the SSC pin and the
VSS pin. Over the entire temperature range, the S-19243xxxA Series operates stably with a ceramic capacitor of 0.68
nF or more. According to CSS capacitance, the rising speed of the output voltage is adjustable. The time that the
output voltage rises to 99% is 6.0 ms typ. at CSS = 10 nF. The recommended value for applications is 0.68 nF ≤ CSS ≤
168 nF, however; define the values by sufficient evaluation including the temperature characteristics under the usage
condition.
 Selection of Resistor for Output Voltage External Setting (Ra, Rb)
The S-19243xxxA Series provides the types in which output voltage can be set via the external resistor. The output
voltage can be set by connecting a resistor (Ra) between the VOUT pin and the VADJ pin, and a resistor (Rb) between
the VADJ pin and the VSS pin.
Depending on the intended output voltage, select Ra and Rb from the range shown in Table 27.
Caution Since the VADJ pin impedance is comparatively high and is easily affected by noise, pay adequate
attention to the wiring pattern.
VOUT
1.0 V
1.05 V to 9.0 V
Table 27
Ra
Connect to VOUT pin
0.1 kΩ to 1.2 MΩ
Rb
Unnecessary
2 kΩ to 200 kΩ
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