SANKEN SI-8000SD_11

1-1-3 DC/DC Converter ICs
SI-8000SD Series
Surface Mount, Separate Excitation Step-down Switching Mode
■Features
■Lineup
• Surface-mount package (TO263-5)
Part Number
SI-8033SD
VO (V)
3.3
• Output current: 3.0A
SI-8050SD
5.0
IO (A)
• High efficiency: 79% typ. (SI-8033SD), 84%
typ. (SI-8050SD)
3
■Absolute Maximum Ratings
• Requires only 4 discrete external components
Parameter
• Internally-adjusted phase correction and
output voltage
• Built-in reference oscillator (60kHz)
Symbol
Ratings
Unit
DC Input Voltage
VIN
43*1
V
Power Dissipation*2
PD
3
W
°C
Conditions
When mounted on glass-epoxy board 40 × 40 mm
(copper area: 100%)
• Built-in overcurrent and thermal protection
circuits
Junction Temperature
Tj
+125
Storage Temperature
Tstg
–40 to +125
°C
Thermal Resistance (Junction to Case)
θ j-c
3
°C/W
• Output ON/OFF available
Thermal Resistance
(Junction to Ambient Air)
θ j-a
33.3
°C/W
• Soft start available by S.S pin
When mounted on glass-epoxy board 40 × 40 mm
(copper area: 100%)
*1: 35V for SI-8033SD
*2: Limited by thermal protection circuit.
■Applications
• Power supplies for telecommunication equipment
• Onboard local power supplies
■Recommended Operating Conditions
Ratings
Parameter
Symbol
SI-8033SD
SI-8050SD
5.5 to 28
7 to 40
Unit
DC Input Voltage Range
VIN1
Output Current Range*
IO
0 to 3.0
V
A
Operating Junction Temperature Range
Tjop
–30 to +125
°C
Operating Temperature Range*
Top
–30 to +125
°C
*: Limited by Ta-PD characteristics.
■Electrical Characteristics
(Ta=25°C)
Ratings
Parameter
Symbol
SI-8033SD
min.
Output Voltage
Line Regulation
Load Regulation
Temperature Coefficient of Output Voltage
Overcurrent Protection
Starting Current
Start
f
Conditions
∆VO/∆Ta
20
5.0
5.2
79
84
VIN=20V, IO=1A
60
60
V
%
kHZ
VIN=20V, IO=1A
80
40
100
mV
VIN=10 to 30V, IO=1A
30
10
40
VIN=15V, IO=0.5 to 1.5A
VIN=20V, IO=0.5 to 1.5A
±0.5
±0.5
mV
mV/°C
3.1
VIN=15V
VIN=20V
0.2
0.2
30
Conditions
40
20
A
V
30
40
µA
VSSL=0.2V
SI-8000SD
SI-8000SD
5 ON/OFF
5 ON/OFF
C3
VOUT. ON/OFF
ICs
max.
VIN=15V, IO=1A
* 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 VSSL 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 C3
flows into the ON/OFF control transistor. Therefore, limit the current securely to protect the
transistor if C3 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.
20
Unit
typ.
VIN=20V, IO=1A
3.1
Conditions
ISSL
4.8
10
Conditions
Outflow Current at
Low Voltage
3.43
VIN=8 to 28V, IO=1A
∆VOLOAD
VSSL
3.3
25
Conditions
Low-Level Voltage
min.
VIN=15V, IO=1A
∆VOLINE
IS1
max.
VIN=15V, IO=1A
Conditions
Oscillation Frequency
Pin*
3.17
η
Efficiency
Soft
VO
Conditions
SI-8050SD
typ.
Soft start
SI-8000SD
5 ON/OFF
C3
Soft start
+VOUT. ON/OFF
SI-8000SD Series
■External Dimensions (TO263-5)
(Unit : mm)
±0.2
10.0
(4.4)
1.2
±0.2
4.5
15.30
±0.3
±0.3
±0.1
±0.2
±0.3
2.0
2.54
±0.2
(0.75)
(R0.3)
0 to 6°
(0.5)
±0.1
±0.1
0.8
±0.25
)
(1.7
±0.25
(1.7
)
1
2
3
4
Plastic Mold Package Type
Flammability: 94V-0
Product Mass: Approx. 1.48g
±0.2
2.4
(R0.3)
4.9
15.3
9.2±
±0.2
±0.15
0.10
(3°)
(3°)
4.9
±0.10
0.88
±0.2
(2×R0.45)
(3°)
(6.8)
±0.2
φ1.5 Dp:
1.3 +0.10
–0.05
9.2
(4.6)
3-R0.3
(1.75)
(15°)
Pin Assignment
q VIN
w SWOUT
e GND
r VOS
t S.S
(8.0)
±0.2
(0.40)
Case temperature
measurement point
(1.7
±0.25
)
0.8
±0.25
(1.7
)
5
±0.2
9.9
(3°)
(3°)
2-R0.3
±0.02
10.0
■Block Diagram
■Reference Data
Copper Laminate Area on Glass Epoxy Board vs.
thermal resistance (junction to ambient air) (Typical Value)
VIN
SWOUT
2
Thermal resistance (junction to ambient air)
θ j-a (°C/W)
1
Overcurrent
protection
Internal power
supply
Oscillator
Reset
Latch & driver
Thermal
protection
Comparator
VOS
4
Error
amplifier
Reference voltage
S.S
55
50
With glass epoxy board of 40 × 40 mm
45
40
35
30
0
200
400
600
800
1000
1200
1400
1600
1800
Copper Laminate Area (mm2)
GND
5
3
■Typical Connection Diagram
L1
1
VIN
SWOUT
VIN
SI-8000SD
C1
+
S.S
5
GND
3
VOS
2
VOUT
4
+
D1
C2
C1 : 50V/1000µF
C2 : 50V/1000µF
C3 : 0.01µF
(only when soft start function is used)
L1 : 150µH
D1 : SPB-G56 (Sanken)
C3
GND
GND
Diode D1
• Be sure to use Schottky-barrier diode as D1.
If other diodes like fast recovery diodes are used, ICs may be destroyed because of the reverse voltage generated by the recovery voltage or ON
voltage.
Choke coil L1
• 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 about 3.5 A, take care concerning heat radiation from the choke coil caused by magnetic saturation
due to overload or short-circuited load.
Capacitors C1, C2, and C3
• As large ripple currents flow through C1 and C2, use high-frequency and low-impedance capacitors aiming for switching-mode-power-supply use.
Especially when the impedance of C2 is high, the switching waveform may become abnormal at low temperatures.
For C2, 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.
• C3 is a capacitor for soft start. Leave pin 5 open if the soft start function is not used.
This pin is pulled up with a pull-up resistor inside the ICs.
To create the optimum operating conditions, place the components as close as possible to each other.
ICs
21