MB3778P Fujitsu Microelectronics, Inc., MB3778P Datasheet - Page 24

• Manufacturer Part Number: MB3778P
• Description: Switching Regulator Controller
• Manufacturer: Fujitsu Microelectronics, Inc.

24
MB3778
Reference data
If an aluminum electrolytic smoothing capacitor (RC 1.0 ) is replaced with a low ESR electrolytic capacitor(OS
CON
60
40
20
20
40
60
40
20
20
40
0
0
10
10
TM
: RC
0.2 ), the phase margin is reduced by half(see Fig. 37 and 38).
100
100
A
V
A
V
Figure 38 DC/DC Converter 5 V output Gain vs. Phase
FB
DC/DC Converter A
Frequency f (Hz)
DC/DC Converter 5 V output Gain vs. Phase
1 k
1 k
C
NF
Error Amp.
62
10 k
10 k
V
REF
IN
IN
V
R
C
27
V
R
C
V
CC
V
R
/2
L
P
CC
L
P
vs.
OUT
1
25
0.1 F
25
0.1 F
10 V
10 V
characteristic Test Circuit
100 k
R
100 k
2
180
90
0
180
90
0
90
180
90
180
V
IN
A
Between these points
V
V
O
vs.
characteristic
R
R
C
C
0.2
1.0
22 F (16 V)
220 F (16 V)
OS CON
AI Capacitor
: f
: f
OSC
OSC
V
GND
V
GND
O
TM
O
1 kHz
1 kHz