■ TECHNICAL NOTES
When using these ICs, consider the following points:
In these ICs, phase compensation is made for securing stable operation even if the load current is varied. For this purpose, use
a capacitor COUT with good frequency characteristics and ESR (Equivalent Series Resistance) of which is in the range
described as follows:
Spectrum
Analyzer
4
2
CE
VOUT
Ceramic
Cap.
R1113ZXX1B
S.A.
ESR
3
VIN
GND
Ceramic
Cap.
1
VIN
IOUT
Measuring Circuit for white noise; R1113ZXX1B
The relations between IOUT (Output Current) and ESR of an output capacitor are shown below. The conditions when the white
noise level is under 40µV(Avg.) are marked as the hatched area in the graph.
(Note: If 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.)
<Measurement conditions>
(1) VIN=VOUT+1V
(2) Frequency Band: 10Hz to 1MHz
(3) Temperature: 25°C
R1113Z201B
R1113Z201B
Cout=2.2uF,Cin=2.2uF
Cout=4.7uF,Cin=2.2uF
100
10
100
10
1
1
0.1
0.1
0.01
0.001
0.01
0.001
0
30
60
90
120
150
0
30
60
90
120
150
Iout[mA]
Iout[mA]
Rev. 1.11
- 19 -
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
