R1171S151A Datasheet, PDF (8/36 Pages) RICOH electronics devices division – 2.0A/1.5A LDO REGULATOR

R1172x
TYPICAL APPLICATION (R1172xxx1B/D)
VDD
VOUT
VOUT
C1
R1172x
Series
C2
CE GND
TECHNICAL NOTES
When using these ICs, consider the following points:
Phase Compensation
In these ICs, phase compensation is made for securing stable operation even if the load current is varied. For
this purpose, use a capacitor C2 with good frequency characteristics and ESR (Equivalent Series Resistance).
The recommendation value is as follows.
Output Voltage C2 recommendation value
Components Recommendation
VOUT < 1.0V
Tantalum 4.7µF or more
1.0 ^<= VOUT ^<= 3.3V
Ceramic 4.7µF or more
Kyocera 4.7µF (1608)
Murata 4.7µF (1608)
Murata _{10µF (1608)}
Part Number : CM105X5R475M06AB
Part Number : GRM188R60J475KE19B
Part Number : GRM188B30G106ME46B
3.3V < VOUT
Ceramic 4.7µF or more
Kyocera 4.7µF (thin 2012) Part Number : CT21X5R475M06AB
Murata 10µF (2012) Part Number : GRM21BB30J106K
∗ If you use a tantalum type capacitor and ESR value of the capacitor is large, output might be unstable.
Evaluate your circuit with considering frequency characteristics.
∗ Depending on the capacitor size, manufacturer, and part number, the bias characteristics and temperature
characteristics are different. Evaluate the circuit with actual using capacitors.
PCB Layout
Make VDD and GND lines sufficient. If their impedance is high, noise pickup or unstable operation may result.
Connect a capacitor C1 with a capacitance value as much as 4.7µF or more between VDD and GND pin, and as
close as possible to the pins.
Set external components, especially the output capacitor C2, as close as possible to the ICs, and make wiring
as short as possible.
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