MB39A125 Datasheet, PDF (40/64 Pages) Fujitsu Component Limited. – DC/DC Converter IC for Charging Li-ion Battery

MB39A125/126
• Frequency Characteristics of LC filter which is using low ESR
Frequency characteristic of power output LC filter
(DC gain is included.)
90
80
70
gain
phase
180
160
140
60
120
50
100
40
Gain
80
30
60
20
40
10
20
0
0
−10
−20
−20
−40
−30
−60
−40 ^Phase
−80
−50
−100
−60
−120
−70
−140
−80
−160
−90
−180
1 10 100 1k 10k 100k 1M 10M
Frequency [Hz]
Cut-off frequency
f1 (Hz) =
2π
1
(Ro + ESR)
Lo × Co ×
(Ro ⁺ RL)
Lo = 15 µH
Co = 14.1 µF
Ro = 4.2 Ω
RL = 30 mΩ
ESR = 100 mΩ
<3Pole2Zero>
DC/DC output
< Additional ESR>
−
+
Board Pattern
or connected
resistor
40