9 Peak Current
(Pulse Load)
10 Using DC-DC
Converters
(2) In the case of Forced Air Cooling (1m/s)
(3) Temperature Measuring Points in the case of Forced Air Cool-
ing (1m/s)
1
SU10
¡
In the case of forced air cooling, please have sufficient ventilation
to keep the temperature of point A in Fig.8.15 at 105
C
or below.
Please also make sure that the ambient temperature does not ex-
ceed 85
C
.
2
SUC10
¡
In the case of forced air cooling, please have sufficient ventilation
to keep the temperature of point B in Fig.8.16 at 95
C
or below.
Please also make sure that the ambient temperature does not ex-
ceed 85
C
.
¡
If a load connected to a converter is a pulse load, you can provide
a pulse current by connecting an electrolytic capacitor externally
to the output side.
¡
The average output current lav is expressed in the following for-
mula.
¡
Required electrolytic capacitor C can be obtained from the follow-
ing formula.
¡
To Operate a Linear IC from 5V Output Power Supply
On-board type
Instruction Manual
G-46
SU.SUC
On-board type
Instruction Manual
G-47
SU.SUC
Fig.8.14 Derating Curve for Forced Air Cooling (1m/s) (SU/SUC10)
Fig.8.15 Temperature Measuring Point in the case of Forced Air Cooling
Fig.8.16 Temperature Measuring Point in the case of Forced Air Cooling
(Upper Surface of the Case)
Ambient Temperature [
C
]
Lo
ad F
ac
to
r [
%
]
-40
-20
0
20
40
60
80
100
0
50
100
(85)
(71)
A
B
Output Voltage(V)
Input Voltage(V)
3.3
5
12
15
�
12
�
15
5
B
B
B
B
A
A
12
B
B
B
B
A
A
24
B
B
B
B
A
A
48
B
B
B
B
B
B
Point A
Point B (Center of the Case)
(Iop - Is)
X
t
T
lav = ls+
(Iop - Iav)
X
t
D
Vo
C =
AC
0
+5V
0
+12V
-15V
0
+15V
-Vin
+Vin
-Vout
+Vout
-Vin
+Vin
-Vout
COM
+Vout
Logic IC
Linear IC
Regulated
DC Power
Supply
Iop
COM
C
+Vin
-Vin
+Vout
-Vout
Pulse Load
External Electrolytic
Capacitor
Vo
D
Vo:Fluctuation of
Output Voltage
Is :Steady-state Current
Iop:Current at Peak
0
0
Iop
Is
D
T
t
Waveform of Pulse
Load Current
Waveform of
Output Voltage
Vo
