1-1-3 DC/DC Converter ICs
SI-8000FFE Series Full-Mold, Separate Excitation Step-down Switching Mode
■Features
• Compact full-mold package (equivalent to
■Lineup
Part Number
SI-8001FFE
Variable (0.8 to 24)
3.5
TO220)
Vo (V)
Io (A)
• Output current: 3.5 A
Function
Soft start
•
High efficiency: 83% (Vo = 5 V, VIN = 15 V, Io = 2 A)
• Requires only 6 discrete components
• Built-in reference oscillator (300 kHz)
■Absolute Maximum Ratings
Ratings
SI-8001FFE
43
Parameter
Symbol
Unit
V
Conditions
• Built-in drooping-type overcurrent and thermal
protection circuits
Input Voltage
VIN
PD1-1
PD1-2
PD2-1
PD2-2
Tj
• Built-in soft start circuit (Output ON/OFF
available)
Power Dissipation
22.7
Limited by thermal protection circuit, Tj=150°C
W
(With infinite heatsink)
Power Dissipation
18.2
Tj=125°C
Limited by thermal protection circuit, Tjmax=150°C
Tj=125°C
2.15
W
(Without heatsink)
1.72
■Applications
• DVD recorder, FPD-TV
Junction Temperature*1
Storage Temperature
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient Air)
+150
°C
°C
Tstg
–40 to +150
5.5
θj-c
°C/W
°C/W
• OA equipment, such as printers
• Onboard local power supplies
θj-a
58
*: 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.
■Recommended Operating Conditions
Ratings
SI-8001FFE
Vo+3*1 to 40
0.8 to 24
Parameter
Symbol
Unit
Input Voltage Range
VIN
VO
IO
V
V
Output Voltage Range
Output Current Range
0 to 3.5
A
Operating Junction Temperature Range
Operating Temperature Range
Tjop
Top
–30 to +125
–30 to +85
°C
°C
*: 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
VADJ
SI-8001FFE
Unit
min.
typ.
max.
0.784
0.800
0.816
V
Reference Voltage
Conditions
∆VADJ/∆T
Conditions
VIN=15V, Io=0.2A
±0.1
mV/°C
Temperature Coefficient of Reference Voltage
Efficiency
VIN=15V, Io=0.2A, Tc=0 to 100°C
η
83
VIN=15V, Io=2A
300
%
Conditions
Conditions
fo
270
3.6
330
kHz
Oscillation Frequency
Line Regulation
VIN=15V, Io=2A
55
∆VOLINE
80
mV
Conditions
VIN=10 to 30V, Io=2A
15
∆VOLOAD
50
mV
Load Regulation
Conditions
VIN=15V, Io=0.2 to 3.5A
IS
A
Overcurrent Protection Starting Current
Low Level Voltage
Conditions
VIN=15V
VSSL
ISSL
0.5
30
V
SS Pin
6
µA
Outflow Current at Low Voltage
Conditions
Conditions
VIN=15V, VSS=0V
6
Iq
mA
VIN=15V, Io=0A
200
Quiescent Circuit Current
Iq(OFF)
600
µA
Conditions
VIN=15V, Vss=0V
*: 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.
SI-8000FFE
SI-8000FFE
SI-8000FFE
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.
5
SS
5
SS
C3
5 SS
C3
VO.ON/OFF
Soft start
Soft start
+Vo. ON/OFF
ICs
44
ETC [ ETC ]
