1-1-3 DC/DC Converter ICs
SI-8000S Series
Full-Mold, Separate Excitation Step-down Switching Mode
■Features
• Compact full-mold package (equivalent to
TO220)
• Output current: 3.0A
• High efficiency: 79 to 91%
• Requires only 4 discrete components
• Internally-adjusted phase correction and output
voltage
• Built-in reference oscillator (60kHz)
• Built-in overcurrent and thermal protection
circuits
• Built-in soft start circuit (Output ON/OFF
available)
■Lineup
Part Number
V
O
(V)
I
O
(A)
SI-8033S
3.3
SI-8050S
5.0
SI-8090S
9.0
3.0
SI-8120S
12.0
SI-8150S
15.0
■Absolute
Maximum Ratings
Parameter
DC Input Voltage
Power Dissipation
Junction Temperature
Storage Temperature
SW Terminal Applied Reverse Voltage
Thermal Resistance(junction to case)
Symbol
V
IN
P
D1
P
D2
T
j
T
stg
V
SW
Ratings
43
*
18(With infinite heatsink)
1.5(Without heatsink, stand-alone operation)
+125
–40 to +125
–1
5.5
Unit
V
W
W
°C
°C
V
°C/W
θ
j-c
*35V for SI-8033S
■Applications
• Power supplies for telecommunication equip-
ment
• Onboard local power supplies
■Recommended
Operating Conditions
Ratings
Parameter
DC Input Voltage Range
Output Current Range
Operating Junction Temperature Range
Symbol
V
IN
I
O
T
jop
SI-8033S
5.5 to 28
SI-8050S
7 to 40
SI-8090S
12 to 40
0 to 3.0
–30 to +125
SI-8120S
15 to 40
SI-8150S
18 to 40
Unit
V
A
°C
■Electrical
Characteristics
Ratings
Parameter
SI-8000S*
1
Output Voltage
SI-8000SS
V
O
Conditions
Efficiency
Oscillation Frequency
Line Regulation
Load Regulation
Temperature Coefficient of
Output Voltage
Overcurrent Protection
Starting Current
Soft
Start Pin*
2
Low-Level Voltage
Outflow Current at
Low Voltage
Symbol
min.
3.17
3.234
SI-8033S
typ.
3.30
3.30
79
V
IN
=15V, I
O
=1.0A
60
V
IN
=15V, I
O
=1.0A
25
10
80
30
V
IN
=8 to 28V, I
O
=1.0A
V
IN
=15V, I
O
=0.5 to 1.5A
±0.5
3.1
V
IN
=15V
3.1
V
IN
=20V
max.
3.43
3.366
min.
4.80
4.90
SI-8050S
typ.
5.00
5.00
84
V
IN
=20V, I
O
=1.0A
60
V
IN
=20V, I
O
=1.0A
40
10
100
40
V
IN
=10 to 30V, I
O
=1.0A
V
IN
=20V, I
O
=0.5 to 1.5A
±0.5
3.1
V
IN
=21V
max.
5.20
5.10
V
IN
=21V, I
O
=1.0A
88
V
IN
=21V, I
O
=1.0A
60
V
IN
=21V, I
O
=1.0A
50
10
120
40
V
IN
=15 to 30V, I
O
=1.0A
V
IN
=21V, I
O
=0.5 to 1.5A
±1.0
3.1
V
IN
=24V
V
IN
=24V, I
O
=1.0A
90
V
IN
=24V, I
O
=1.0A
60
V
IN
=24V, I
O
=1.0A
60
10
130
40
V
IN
=18 to 30V, I
O
=1.0A
V
IN
=24V, I
O
=0.5 to 1.5A
±1.0
3.1
V
IN
=25V
V
IN
=25V, I
O
=1.0A
91
V
IN
=25V, I
O
=1.0A
60
V
IN
=25V, I
O
=1.0A
60
10
130
V
IN
=21 to 30V, I
O
=1.0A
40
V
IN
=25V, I
O
=0.5 to 1.5A
±1.0
min.
8.55
SI-8090S
typ.
9.00
max.
9.45
min.
11.50
SI-8120S
typ.
12.00
max.
12.50
min.
14.25
SI-8150S
typ.
15.00
max.
15.75
(T
a
=25°C)
Unit
V
V
IN
=15V, I
O
=1.0A
V
IN
=20V, I
O
=1.0A
η
Conditions
f
Conditions
∆V
OLINE
Conditions
∆V
OLOAD
Conditions
∆V
O
/∆T
a
I
S1
Conditions
V
SSL
I
SSL
Conditions
%
kH
Z
mV
mV
mV/°C
A
V
15
0.2
25
35
15
0.2
25
35
15
0.2
25
V
SSL
=0.2V
35
15
0.2
25
35
15
0.2
25
35
µ
A
*1:“S” may be printed to the right of the marking (except SI-8090S, SI-8120S, SI-8150S).
*2:Pin 5 is a soft start pin. Soft start at power on can be performed with a capacitor connected to
this pin.
The output can also be turned ON/OFF with this pin.
The output is stopped by setting the voltage of this pin to V
SSL
or lower.
Soft-start pin voltage can be changed with an open-collector drive circuit of a transistor.
When using both the soft-start and ON/OFF functions together, the discharge current from C
3
flows into the ON/OFF control transistor. Therefore, limit the current securely to protect the
transistor if C
3
capacitance is large.
The ON/OFF pin is pulled up to the power supply in the IC, so applying the external voltage is
prohibited.
If this pin is not used, leave it open.
SI-8000S
SI-8000S
SI-8000S
5 ON/OFF
5 ON/OFF
C3
5 ON/OFF
C3
V
OUT.
ON/OFF
Soft start
Soft start
+V
OUT.
ON/OFF
46
ICs
SI-8000S Series
■External
Dimensions (TO220F-5)
0.5
(Unit : mm)
4.2
±0.2
2.8
±0.2
10.0
±0.2
4.0
±0.2
7.9
±0.2
16.9
±0.3
φ
3.2
±0.2
(17.9)
2.6
±0.1
(2.0)
0.95
±0.15
+0.2
0.85
–0.1
0.45
–0.1
P1.7
±0.7
×4=6.8
±0.7
+0.2
Pin Assignment
q
V
IN
w
SW
OUT
e
GND
r
V
OS
t
S.S
Plastic Mold Package Type
Flammability: UL94V-0
Product Mass: Approx. 2.3g
(4.6)
3.9
±0.7
(4.3)
8.2
±0.7
1 2 3 4 5
Forming No. 1101
■Block
Diagram
V
IN
1
Reg.
OSC
Reset
OCP
2 SW
OUT
Drive
Comp.
TSD
4 V
OS
Amp.
V
REF
5 S.S.
3 GND
■Typical
Connection Diagram
V
IN
1
2
V
IN
SW
OUT
L
1
V
O
(8.0)
+
C
1
SI-8000S
V
OS
S.S
5
GND
3
4
D
1
+
C
2
C
1,2
: 1000
µ
F
L
1
: 150
µ
H
D
1
: RK46(Sanken)
GND
GND
■T
a
-P
D
Characteristics
20
Infinite heatsink
P
D
=V
O
•I
O
With Silicone Grease
Heatsink: Aluminum
100
–1
ηχ
–V
F
•I
O
1–
V
O
V
IN
Power Dissipation P
D
(W)
15
200×200×2mm
(2.3°C/W)
The efficiency depends on the input voltage and the output current.
Therefore, obtain the value from the efficiency graph and substi-
tute the percentage in the formula above.
V
O
V
IN
I
O
ηx
V
F
:
:
:
:
:
Output voltage
Input voltage
Output current
Efficiency (%)
Diode D
1
forward voltage
0.5V(RK46)
100×100×2mm
10 (5.2°C/W)
75×75×2mm
(7.6°C/W)
5
Without heatsink
0
–25
0
25
50
75
100
125
Operating Ambient Temperature T
a
(°C)
Thermal design for D
1
must be considered separately.
ICs
47
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