s
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 2.2µF or more capacitor C
OUT
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.)
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 as much as 1.0µF capacitor between V
DD
and GND pin as close as possible.
Set external components, especially output capacitor as close as possible to the ICs and make wiring shortest.
s
TEST CIRCUITS
1
V
OUT
I
OUT
V
OUT
V
C2
V
DD
R1141Q
SERIES
4
2
GND
CE
3
C1
*
C1 = Ceramic 1.0µF
C2 = Ceramic 2.2µF
Fig.1 Standard test Circuit
1
V
OUT
C2
V
DD
R1141Q
SERIES
CE
4
A
3
C1
I
SS
2
GND
*
C1 = Ceramic1.0µF
C2 = Ceramic 2.2µF
Fig.2 Supply Current Test Circuit
Rev. 1.10
-5-
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
