qSI-8400L/8500L
Series
SI-8400L/8500L Series
Separate Excitation Switching Type with Coil
sFeatures
•
•
•
•
•
•
Integrated switching IC and coil construction
Requires 2 external components only
Low switching noise
Heatsink not required
Built-in overcurrent and thermal protection circuits
Built-in soft start circuit (Output ON/OFF control)...SI-8500L Series
sApplications
• Telephone power supplies
• Onboard local power supplies
sLineup
Part Number
V
O
(V)
I
O
(A)
SI-8401L
5.0
0.5
SI-8402L
12.0
0.4
SI-8403L
3.3
0.5
SI-8405L
15.0
0.4
SI-8501L
5.0
SI-8502L
12.0
SI-8503L
3.3
1.0
SI-8504L
9.0
SI-8505L
15.0
sAbsolute
Maximum Ratings
Parameter
DC Input Voltage
Power Dissipation
Junction Temperature
Storage Temperature
Symbol
SI-8400L
V
IN
P
D
T
j
T
stg
1.25
+100
–25 to +85
35
3
Ratings
SI-8500L
V
W
°C
°C
Unit
sRecommended
Operating Conditions
Parameter
DC Input Voltage Range
Output Current Range
Operating Temperature Range
Symbol
SI-8401L
V
IN
I
O
T
op
7 to 33
0 to 0.5
15 to 33
0 to 0.4
Ratings
SI-8402L
SI-8403L
5.3 to 33
0 to 0.5
SI-8405L
18 to 33
0 to 0.4
V
A
°C
Unit
–20 to +85
Parameter
DC Input Voltage Range
Output Current Range
Operating Temperature Range
Symbol
SI-8501L
V
IN
I
O
T
op
7 to 33
SI-8502L
15 to 33
Ratings
SI-8503L
5.3 to 33
0 to 1.0
–20 to +85
SI-8504L
12 to 33
SI-8505L
18 to 33
Unit
V
A
°C
96
qSI-8400L/8500L
Series
sT
a
-P
D
Characteristics
1.5
3.0
SI-8400L
Power Dissipation P
D
(W)
SI-8500L
P
D
=V
O
•I
O
100
–1
ηχ
Power Dissipation P
D
(W)
1.0
2.0
V
O
:Output voltage
I
O
:Output current
ηχ
:Efficiency (%)
The efficiency depends on the input
voltage and the output current. Thus,
obtain the value from the efficiency
graph and substitute the percentage
in the formula above.
0.5
1.0
0
0
25
50
75
100
0
0
25
50
75
100
Ambient Temperature T
a
(°C)
Ambient Temperature T
a
(°C)
sSI-8500L
application circuit
Terminal no.2 is for soft start. Connecting a capacitor to the terminal
enables the soft start function. See page 85 for the formulas to calcu-
late delay time and rise time. Output can be turned on and off by
using the soft start terminal. To stop output, set the soft start terminal
voltage to V
SSL
(0.2V typ.) or less. To switch the potential of the soft
start terminal, drive the open collector of the transistor. Since the
discharge current from C
3
flows to the ON/OFF control transistor, limit
the current for protection. The SS terminal is pulled up to the power
supply in the IC and no external voltage can be applied.
SI-8500L
SI-8500L
SI-8500L
2 S.S.
2 S.S.
C
3
2 S.S.
C
3
V
O.
ON/OFF
Soft start
Soft start +V
O
ON/OFF
sCaution
1. Allocation of Components
For the best operating environment, the ground should be a single ground line at the GND terminal (terminal 2 on the SI-8400L, terminal 3 on
the SI-8500L), and the wiring from C
1
and C
2
to ground should be as short as possible.
2. Capacitors C
1
and C
2
1) They must satisfy the breakdown voltage and allowable ripple current.
Exceeding the ratings of these capacitors or using them without derating shortens their service lives and may also cause abnormal
oscillation of the IC.
2) C
2
must be a low-impedance type capacitor to ensure minimum ripple voltage and stable switching operation.
3) C
3
(SI-8500L only) is a capacitor for soft start. When not using soft start, leave terminal 2 open. It is pulled up inside the IC.
3. Terminals LIN and NC in the connection diagram must be left unconnected to other circuits.
4. The IC's metalic heatsink is electrically floating. Do not connect it to GND or any other circuit.
5. Since the SI-8400L and 8500L series have an open-package construction, they can only be operated in specific environments. Verify the
operating environment and use the conditions indicated in the reliability data.
99
qSI-8400L/8500L
Series
sTypical
Characteristics (SI-8400L Series)
Rise Characteristics(SI-8401L)
6
T
a
=25°C
Efficiency Characteristics(SI-8401L)
100
T
a
=25°C
Load Regulation(SI-8401L)
5.3
T
a
=25°C
5
90
20V
25V
33V
10V
7V
5.2
Output Voltage V
O
(V)
Output Voltage V
O
(V)
0.1A
Efficiency
η
(%)
4
A
80
V
IN
7V
10V
5.1
V
IN
=33V
5.0
10V
7V
20V
=0
3
2
I
O
0.5
A
0.3A
70
20V
60 25V
33V
50
4.9
1
4.8
0
0
0
0
2
4
6
8
10
0
0
0.1
0.2
0.3
0.4
0.5
0.1
0.2
0.3
0.4
0.5
Input Voltage V
IN
(V)
Output Current I
O
(A)
Output Current I
O
(A)
Temperature Characteristics(SI-8401L)
100
V
IN
=20V, I
O
=0.3A
5.3
5.2
5.1
5.0
4.9
f
50
40
0 –40
–20
0
20
40
60
80
4.8
4.7
100 0
Overcurrent Protection Characteristics(SI-8401L)
6
T
a
=25°C
Thermal Protection Characteristics(SI-8401L)
6
V
IN
=20V, I
O
=20mA
Efficiency
η
(%) Frequency f (kHz)
90
80
70
60
η
5
5
20V
Output Voltage V
O
(V)
Output Voltage V
O
(V)
Output Voltage V
O
(V)
1.5
2.0
4
3
=7
V
4
V
V
IN
V
O
2
33
3
2
1
0
0
1
0
0.5
1.0
0
50
100
150
200
Ambient Temperature T
a
(°C)
Output Current I
O
(A)
Case Temperature T
C
(°C)
Note on Thermal Protection:
The thermal protection circuit is intended for pro-
tection against heat during instantaneous short-
circuiting. Its operation is not guaranteed for short-
circuiting over extended periods of time.
Rise Characteristics(SI-8402L)
14
12
T
a
=25°C
Efficiency Characteristics(SI-8402L)
100
T
a
=25°C
Load Regulation(SI-8402L)
12.3
T
a
=25°C
90
12.2
33
24
V
I
V
V
N
=
15
V
Output Voltage V
O
(V)
Efficiency
η
(%)
10
Output Voltage V
O
(V)
0.2A
80
12.1
V
IN
=33V
24V
20V
15V
11.9
0.
4A
I
O
=
8
6
4
2
0
0
0A
70
12.0
60
50
0
0
11.8
5
10
15
20
0.1
0.2
0.3
0.4
0
0
0.1
0.2
0.3
0.4
Input Voltage V
IN
(V)
Output Current I
O
(A)
Output Current I
O
(A)
100
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