SPI-8001TW/SPI-8002TW/SPI-8003TW
sTypical
Connection Diagram
V
IN
3
V
CC
2
V
IN1
Ch1
V
REF1
5
DGND1
SPI-8000TW
15
V
IN2
SWout2
13
V
02
L2
11
R6
SS2
Ch2
10
Di2
R3
+
V
C/E
14
C/E
SWout1
4
L1
V
01
Di1
R1
+
V
IN
3
V
CC
2
V
IN1
Ch1
V
REF1
5
DGND1
SPI-8003TW
16
V
IN2
SWout2
14
7
15
C/E
SWout1
4
L1
V
C/F
V
C1
Di1
R1
+
6
R5
SS1
6
C2
C7
7
SS1
R5
C2
I
REF1
R2
C7
I
REF1
R2
C4
+
C5
+
C6
C1
C4
C1
V
C2
L2
Di2
R3
+
12
C3
C8
SS2
V
REF2
Ch2
12
R6
V
REF2
11
DGND2
AGND
1, 9
I
REF2
13
C3
DGND2
AGND
1, 9
8
C9
C
ORC
R
CSC
10
R7
I
REF2
R4
C8
R4
C5
GND
C6
GND
C1
C2, C3
C4, C5
C6, C7, C8
: 220
µ
F/50V
: 470
µ
F/25V
: 1
µ
F
: 0.1
µ
F
R5, R6
L1, L2
Di1, Di2
(Sanken)
: 1kΩ
: 47
µ
H
: SJPB-H6
GND
GND
C1
C2, C3
C4
C5, C6
C7, C8
: 220
µ
F/50V
: 470
µ
F/25V
: 1
µ
F/50V
: 1
µ
F/10V
: 0.1
µ
F/50V
C9
L1, L2
R2, R4
R5, R6
Di1, Di2
: 100pF/10V
: 47
µ
H
: 1kΩ
: 1kΩ
: SJPB-H6 (Sanken)
Diodes Di1, Di2
• Be sure to use Schottky-barrier diodes for Di1 and Di2.
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 coils L1, L2
• 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 2.0A, take care concerning heat radiation from the choke coil caused by magnetic saturation due to
overload or short-circuited load.
• Use a closed-magnetic-path coil to prevent interference between the channels SW
out
1 and SW
out
2.
Capacitors C1, C2, C3
• As large ripple currents flow through C1, C2 and C3, use high-frequency and low-impedance capacitors suitable for switching mode power supplies.
Especially when the impedance of C2 and C3 are high, the switching waveforms may become abnormal at low temperatures. For C2 and C3, do not use
capacitors with extremely low equivalent series resistance (ESR) such as OS capacitors or tantalum capacitors, which may cause abnormal oscillation.
Resistors R1, R2, R3, R4
• R1, R2, R3 and R4 are resistors for setting output voltages. Set the resistors so that I
REF
is approx. 1 mA. For example, R1 and R2 can be calculated as
shown below.
R1=
(V
O1
–V
REF1
)
(V
O1
–V)
V
REF1
1
.
=
1(K
)
=
(
), R2=
=
1
×
10
–3
I
REF1
1
×
10
–3
.
I
REF1
To create the optimum operating conditions, place the components as close as possible to each other.
sT
a
-P
D
Characteristics
3.5
θ
j-a (Copper Laminate Area)
35.8°C/W (30.8 cm
2
)
3.0
38.2°C/W (15.6 cm
2
)
42.6°C/W (8.64 cm
2
)
Power Dissipation P
D
(W)
P
D
= V
O
·I
O
2.5
52.3°C/W (3.34 cm
2
)
100
V
O
–1 – V
F
·I
O
1–
ηχ
V
IN
2.0
69.2°C/W (0.84 cm
2
)
1.5
1.0
0.5
0.0
–25
V
O
:
V
IN
:
I
O
:
ηχ
:
V
F
:
Output Voltage
Input Voltage
Output Current
Efficiency (%)
D
1
Forward Voltage
SJPB-H6···0.45V (I
O
=1A)
0
25
50
75
100
125 135 150
Ambient Temperature T
a
(°C)
Note 1: The efficiency depends on the input voltage and the output current. Therefore, obtain 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.
ICs
89
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