1-1-3 DC/DC Converter ICs
SI-8000GL Series
■Features
Compact, Separate Excitation Step-down Switching Mode
■Absolute
Maximum Ratings
Parameter
DC Input Voltage
Power Dissipation
Junction Temperature
Storage Temperature
Thermal Resistance (junction to case)
Thermal Resistance (junction to ambient air)
Symbol
V
IN
P
D*1
T
j
T
stg
Ratings
53
1
+125
–40 to +125
28
100
Unit
V
W
°C
°C
°C/W
°C/W
• DIP 8 pin package
• Output current: 1.5A
• High efficiency: 86% (at V
IN
= 20V, l
O
= 1A, V
O
= 5V)
• Capable of downsize a choke-coil due to IC's
high switching frequency (250kHz). (Com-
pared with conventional Sanken devices)
• The output-voltage-variable type can vary its
output voltage from 1V to 14V because of its
low reference voltage (Vref) of 1V.
• Wide Input Voltage Range (8 to 50V)
• Output ON/OFF available
• Built-in overcurrent protection and thermal
protection circuits
θ
j-c
θ
j-a
*1: Limited by thermal protection.
■Applications
• Onboard local power supplies
• OA equipment
• For stabilization of the secondary-side output voltage of switching power supplies
■Recommended
Operating Conditions
Ratings
Parameter
DC Input Voltage Range
Output Voltage Range
Output Current Range
*2
Operating Junction Temperature Range
Operating Temperature Range
Symbol
V
IN
V
O
I
O
T
jop
T
op
SI-8010GL
(8 or V
O
+3)
*1
to 50
1 to 14
0.02 to 1.5
*2
–30 to +125
–30 to +125
Unit
V
V
A
°C
°C
*1: The minimum value of an input voltage range is the higher of either 8V or V
O
+3V.
*2: Please be sure to let the output current run more than 20 mA. When using by less than 20 mA, there is a possibility that the output voltage becomes unstable.
■Electrical
Characteristics
Ratings
Parameter
Symbol
min.
Reference Voltage
Efficiency
Oscillation Frequency
Line Regulation
Load Regulation
Temperature Coefficient
of Reference Voltage
Overcurrent Protection
Starting Current
Quiescent Circuit Current
Circuit Current at Output OFF
CE/SS
*
Terminal
Low Level Voltage
Terminal Outflow
Current at Low Voltage
V
REF
Conditions
Eff
Conditions
F
OSC
Conditions
∆V
OLINE
Conditions
∆V
OLOAD
Conditions
∆V
REF
/∆T
a
I
S
Conditions
I
q
Conditions
I
q
(
OFF
)
Conditions
V
SSL
I
SSL
Conditions
V
SSL
=0V
V
IN
=12V, V
ON/OFF
=0.3V
0.5
50
1.6
V
IN
=12V
7
V
IN
=12V, I
O
=0A
400
0.97
SI-8010GL (Variable type)
typ.
1.00
V
IN
=12V, I
O
=1A
86
V
IN
=20V, I
O
=1A, V
O
=5V
250
V
IN
=12V, I
O
=1A
20
V
IN
=10 to 30V, I
O
=1A
10
V
IN
=12V, I
O
=0.1 to 1.5A
±0.5
30
40
max.
1.03
(T
a
=25°C)
Unit
V
%
kH
Z
mV
mV
mV/°C
A
mA
µ
A
V
µ
A
*: Pin 2 is the CE/SS 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. CE/SS-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
4
flows into the ON/OFF control transistor. Therefore, limit the current securely to
protect the transistor if C
3
capacitance is large. The CE/SS pin is pulled up to the power
supply in the IC, so applying the external voltage is prohibited.
SI-8000GL
SI-8000GL
SI-8000GL
2 CE/SS
2 CE/SS
C4
2 CE/SS
C4
V
O.
ON/OFF
Soft start
Soft start
+V
O.
ON/OFF
38
ICs
SI-8000GL Series
■External
Dimensions (DIP8)
6.5±0.2
(Unit: mm)
8
7
6
5
1
2
3
4
9.4±0.3
4.2±0.3
1.0
+0.3
-0.05
1.5
+0.3
-0.05
7.5±0.5
7.6
Pin Assignment
1. GND
2. CE/SS
3. Reg
4. SW
OUT
5. V
IN
6. B.S
7. C
omp
8. V
REF
Plastic Mold Package Type
Flammability: UL 94V-0
Product Mass: Approx. 0.49 g
3.4±0.1
+0.1
0.25
-0.05
0.5±0.1
2.54
0.89 TYP
3.3±0.2
0.25
M
0° to 15°
■Block
Diagram
SI-8010GL
■T
a
-P
D
Characteristics
2
1.8
P
D
=V
O
• I
O
100
V
O
–1 –V
F
• I
O
1–
ηχ
V
IN
Power Dissipation P
D
(W)
V
IN
1.6
1.4
1.2
θ
j-a:100°C/W
UVLO
CE/SS
CE/SS
P.REG
OCP
BS
Boot REG
TSD
1
0.8
0.6
0.4
0.2
DRIVE
Reg
OSC
+
-
PWM
LOGIC
SW
OUT
Note 1: The efficiency depends on the input volt-
age and the output current. Therefore, ob-
tain the value from the efficiency graph and
substitute the percentage in the formula
above.
Note 2: Thermal design for D
1
must be considered
separately.
25
50
75
100
125
V
REF
Comp
-
Amp
+
0
–25
0
Ambient Temperature T
a
(°C)
1V
GND
V
O
: Output voltage
V
IN
: Input voltage
I
O
: Output current
ηχ
: Efficiency
V
F
: Diode D
1
forward voltage
RK16···0.4V(I
O
=1A)
■Typical
Connection Diagram
SI-8010GL
6
B.S
5
R1
L1
C3
V
IN
2
C1
V
IN
CE/SS
C7
SI-8010GL
Comp
7
C5
C6
SW
OUT
4
D1 R2
V
0
+
Reg
3
C4
GND
1
V
REF
+
C2
C8
I
REF
8
R3
C1: 220
µ
F/63V
C2: 470
µ
F/25V
C3: 0.1
µ
F
C4: 1000pF
C5: 0.1
µ
F
C6: 0.047
µ
F
C7: 0.1
µ
F
R2=
C8: 0.1
µ
F
R1: 47Ω
L1: 47
µ
H
D1: RK16
(Sanken)
GND
GND
Diode D
1
• Be sure to use a Schottky-barrier diode as D
1
. If other diodes like fast recovery diodes are used, IC may be destroyed because of the reverse voltage generated
by the recovery voltage or ON voltage.
Choke coil L
1
• If the winding resistance of the choke coil is too high, the efficiency may drop below the rated value.
• As the overcurrent protection starting current is approx. 2.5 A, take care concerning heat radiation from the choke coil caused by magnetic saturation due to
overload or short-circuited load.
Capacitor C
1
, C
2
• As large ripple currents flow through C
1
and C
2
, use high-frequency and low-impedance capacitors aiming for switching-mode-power-supply use. Especially
when the impedance of C
2
is high, the switching waveform may become abnormal at low temperatures. For C
2
, do not use a capacitor with an extremely low
equivalent series resistance (ESR) such as an OS capacitor or a tantalum capacitor, which may cause an abnormal oscillation.
Resistors R
2
, R
3
• R
2
and R
3
are the resistors to set the output voltage. Set their values so that I
REF
becomes approx. 2 mA. Obtain R
2
and R
3
values by the following formula above.
* To create the optimum operating conditions, place the components as close as possible to each other.
V
REF
(V
OUT
–V
REF
) (V
OUT
–1)
1
.
= 500(Ω)
=
(Ω), R3 =
=
.
–3
–3
2×10
I
REF
2×10
I
REF
ICs
39
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