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R1122N Datasheet, PDF (8/22 Pages) RICOH electronics devices division – LOW NOISE 150mA LDO REGULATOR  
n 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, be
sure to use a capacitor COUT with good frequency characteristics and ESR (Equivalent Series Resistance).
(note: When the additional ceramic capacitors are connected to the Output Pin with Output capacitor for phase compensation,
the operation might be unstable. Because of this, test these ICs with as same external components as ones to be used on the
PCB.)
Recommended Capacitors; GRM40X5R225K6.3 (Murata)
GRM40-034X5R335K6.3 (Murata)
GRM40-034X5R475K6.3 (Murata)
PCB Layout
Make VDD and GND line sufficient. When the impedance of these is high, it would be a cause of picking up the noise or
unstable operation. Connect a capacitor with a capacitance of 2.2mF or more between VDD and GND pin as close as possible.
Set external components, especially output capacitor as close as possible to the ICs and make wiring shortest.
Rev. 1.10
-8-