1-1-3 DC/DC Converter ICs
SI-8000Q Series Surface Mount, Current Mode Cntrol Step-down Switching Mode
■Features
■Absolute Maximum Ratings
• Compact surface-mount package (HSOP8)
• Introduction of current mode control method
• Output current: 3.5 A
Parameter
Symbol
Ratings
Unit
V
Conditions
Input Voltage
Power Dissipation*1
Junction Temperature*2
VIN
30
PD
1.35
W
When mounted on glass-epoxy board, 30×30 mm (copper laminate area: 25×25 mm)
Tj
–30 to +150
–40 to +150
40
°C
• High efficiency: 90% (Vo = 5 V)
• Built-in reference oscillator (500 kHz)
• A ceramic capacitor can be used for output
Storage Temperature
Tstg
θj-c
°C
Thermal Resistance(junction to case)
Thermal Resistance(junction to ambient air)
°C/W
°C/W
θj-a
74
When mounted on glass-epoxy board, 30×30 mm (copper laminate area: 25×25 mm)
*1: Limited by thermal protection circuit
*2: Note that the detection temperature for thermal protection is about 140°C.
• Built-in drooping-type overcurrent and thermal
protection circuits
• Built-in soft start circuit
• Built-in on/off function (Active Hi)
• Low current consumption during off
■Applications
• DVD recorder, FPD-TV
• Onboard local power supplies
• OA equipment
■Recommended Operating Conditions
Ratings
SI-8005Q
Vo+3*1 to 28
0.5 to 24
Unit
Conditions
Parameter
Symbol
DC 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
*1: The minimum value of the input voltage range is 4.75 V or Vo +3 V, whichever is higher.
■Electrical Characteristics
(R1=4.2kΩ, R2=0.8kΩ when Ta = 25°C and Vo=5V)
Rating
SI-8005Q
typ.
Parameter
Symbol
VADJ
Unit
min.
max.
0.485
0.500
0.515
V
Reference Voltage
Conditions
∆VADJ/∆T
Conditions
VIN=12V, Io=1A
0.05
mV/°C
Temperature Coefficient of Reference Voltage
Efficiency
VIN=12V, Io=1A, Ta=–40 to +85°C
η
90
VIN=12V, Io=1A
500
%
kHz
mV
mV
A
Conditions
Conditions
fo
450
3.6
550
60
Oscillation Frequency
VIN=16V, Io=1A
30
∆VOLINE
Line Regulation
Conditions
VIN=8 to 28V, Io=1A
30
∆VOLOAD
60
Load Regulation
Conditions
VIN=12V, Io=0.1 to 3.5A
IS
6.0
Overcurrent Protection Starting Current
Conditions
Conditions
VIN=12V
18
Iq
mA
µA
µA
V
VIN=12V, Io=0A, VEN=open
Quiescent Circuit Current
Iq(OFF)
20
Conditions
VIN=12V, Io=0A, VEN=0V
ISSL
Vc/EN
Vc/EL
IC/EH
5
SS Pin Outflow Current at Low Voltage
High Level Voltage
Conditions
Conditions
Conditions
Conditions
VIN=16V, VSSL=0V
2.8
VIN=12V
2.2
V
EN Pin Low Level Voltage
Inflow Current at Low Low Voltage
VIN=12V
5
µA
VEN=0V
1000
800
Error Amplifier Voltage Gain
Error Amplifier Transformer Conductance
Current Sense Amplifier Impedance
Maximum ON Duty
AEA
GEA
V/V
µA/V
V/A
1/GCS
DMAX
DMIN
0.35
92
%
Minimum ON Time
100
nsec.
*: Pin 8 is the SS pin. Soft start at power on can be performed with a capacitor connected to this pin.
The SS pin is pulled up to the power supply in the IC, so applying the external voltage is prohibited.
SI-8008Q
8
SS
C8
ICs
26
Soft start
ETC [ ETC ]
