1-1-3 DC/DC Converter ICs
SI-8000FD Series Surface Mount, Separate Excitation Step-down Switching Mode
■Lineup
■Features
• Surface-mount package (TO263-5)
Part Number
SI-8001FDE
Soft start
SI-8001FDL
ON/OFF
• Output current: 3.5 A
VO(V)
Variable(0.8 to 24)
3.5
IO(A)
• High efficiency: 83% (Vo = 5 V, VIN = 15 V, Io = 2 A)
• Requires only 6 discrete components
• Built-in reference oscillator (300 kHz)
Function
■Absolute Maximum Ratings
• Built-in drooping-type overcurrent and thermal
protection circuits
Ratings
SI-8001FDE SI-8001FDL
43
Parameter
Symbol
Unit
Conditions
• Built-in soft start circuit (Output ON/OFF
available)
Input Voltage
VIN
Vc
V
V
- SI-8001FDE
ON/OFF Control Voltage
–
VIN
Power Dissipation*1
Junction Temperature*2
PD
Tj
3
+150
W
°C
When mounted on glass-epoxy board measuring 40×40 mm (copper laminate area: 100%)
• Built-in on/off function (active Low)
- SI-8001FDL
Storage Temperature
Tstg
θj-c
θj-a
–40 to +150
3*1
33.3*1
°C
• Low current consumption during off
- SI-8001FDL
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient Air)
°C/W
°C/W
When mounted on glass-epoxy board measuring 40×40 mm (copper laminate area: 100%)
When mounted on glass-epoxy board measuring 40×40 mm (copper laminate area: 100%)
*1 : Limited by thermal protection circuit
■Applications
• DVD recorder, FPD-TV
*2 : This product has built-in thermal protection circuits that may activate when the junction temperature exceeds 130°C.
The recommended design for the junction temperature during IC operation is below 125°C.
• OA equipment, such as printers
• Onboard local power supplies
■Recommended Operating Conditions
Ratings
Parameter
Symbol
Unit
SI-8001FDE
SI-8050FDL
Input Voltage Range
VIN
VO
IO
Vo+3*1 to 40
0.8 to 24
V
V
Output Voltage Range
Output Current Range
0 to 3.5
A
Operating Junction Temperature Range
Operating Temperature Range
Tjop
Top
–30 to +100
–30 to +85
°C
°C
*1: The minimum value of the input voltage range is 4.5 V or Vo + 3 V, whichever is higher.
■Electrical Characteristics
(R1=4.2kΩ, R2=0.8kΩ when Ta = 25°C and Vo=5V)
Ratings
Parameter
Symbol
SI–8001FDE
SI–8001FDL
Unit
min.
typ.
max.
min.
0.784
typ.
max.
VADJ
Conditions
∆VADJ/∆T
Conditions
η
0.784
0.800
0.816
0.800
0.816
V
mV/°C
%
Reference Voltage
VIN=15V, Io=0.2A
VIN=15V, Io=0.2A
±0.1
±0.1
Temperature Coefficient of Reference Voltage
Efficiency
VIN=15V, Io=0.2A, Tc=0 to 100°C
VIN=15V, Io=0.2A, Tc=0 to 100°C
83
83
Conditions
fO
VIN=15V, Io=2A
300
VIN=15V, Io=2A
300
270
3.6
330
80
270
330
80
kHz
mV
Oscillation Frequency
Line Regulation
Conditions
∆VOLINE
Conditions
∆VOLOAD
Conditions
IS
VIN=15V, Io=2A
VIN=15V, Io=2A
VIN=10 to 30V, Io=2A
VIN=15V, Io=0.2 to 3.5A
VIN=15V
VIN=10 to 30V, Io=2A
50
50
mV
Load Regulation
VIN=15V, Io=0.2 to 3.5A
3.6
A
V
Overcurrent Protection Starting Current
Low Level Voltage
Conditions
VSSL
VIN=15V
0.5
30
–
–
–
–
–
–
–
–
SS Pin*1
Outflow Cuurent
ISSL
6
µA
at Low Voltage
Conditions
Vc, IH
Vc, IL
Ic, IH
VIN=15V, VSS=0V
–
ON/OFF Control Voltage (Output on)
ON/OFF Control Voltage (Output off)
–
–
–
–
–
–
–
0.8
V
V
–
2.0
ON/OFF Pin*2
–
6
100
200
ON/OFF Controll Current (Output on)
µA
mA
µA
Conditions
Iq
–
Vc=2V
6
6
Conditions
Iq(OFF)
Conditions
VIN=15V, Io=0A
200
VIN=15V, Io=0A
30
Quiescent Circuit Current
600
VIN=15V, Vss=0V
VIN=15V, Vc=2V
*1: Pin 5 is the 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 VSSL or lower. 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 C3 flows into the ON/OFF control transistor.
Therefore, limit the current securely to protect the transistor if C3 capacitance is large. The
SS pin is pulled up (3.7 V typ.) to the power supply in the IC, so applying the external
voltage is prohibited. If this pin is not used, leave it open.
SI-8001FDE
SI-8001FDE
SI-8001FDE
5
SS
5
SS
C3
5 SS
C3
*2: Output is OFF when the output control terminal VC is open. Each input level is equivalent to
LS-TTL. Therefore, the device can be driven directly by LS-TTLs.
VO.ON/OFF
Soft start
Soft start
+Vo. On/OFF
ICs
28
ETC [ ETC ]
