R1110N
APPLICATION HINTS
When using these ICs, be sure to take care of following points :
• 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) of which is in the range described as follows :
The relations between IOUT (Output Current) and ESR of 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 : When the additional ceramic capacitors are connected to the Output Pin with Output capacitor for
phase compensation, there are possibilities that the operation will be unstable. Because of this, test these
ICs with as same external components as ones to be used on the PCB.)
< measuring conditions >
VIN=4V
Freqency band : 10Hz to 1MHz
Temperature : 25˚C
• Make VDD and GND line sufficient. When the impedance of these is high, there is a case to pick up the noise or
not to work correctly.
• Connect the capacitor with a capacitance of 1µF or more between VDD and GND as close as possible.
• Set external components, especially Output Capacitor, as close as possible to the ICs and make wiring
shortest.
Ceramic Capacitor 4.7µF
Ceramic Capacitor 6.8µF
100
10
1
100
10
1
0.1
0.1
0
50
80
150
0
50
80
150
Output Current IOUT(mA)
Output Current IOUT(mA)
Ceramic Capacitor 10µF
100
10
1
• Measuring Circuit for white noise ; R1110N301B
3
CE
VOUT
5
Ceramic
Capacitor
R1110N301B
S.A.
Spectrum
Analyzer
ESR
1
VIN
GND
IOUT
2
Ceramic
Capacitor1µF
VIN
0.1
0
50
80
150
Output Current IOUT(mA)
17
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