
89
I
Standard External Circuit
I
Notes of Pattern Design
1) Thick lines in the Standard External Circuit are lines through which a large current flows. Make these pattern lines as thick as possible.
2) Place capacitor C
1
on the input side as closely as possible to terminals no.2 and no.4 of the STR7000/7100 series. C
1
may be used in
combination with a smoothing capacitor for rectifying, but the above points must be taken into consideration. In cases where C
1
is not provided
or it is placed too far from the terminals stated above, abnormal oscillation due to poorer transient response or increased ringing may occur.
3) Connect voltage sensing terminal V
O.S
and GND as closely as possible to output capacitor C
4
(a current of approximately 1mA flows into the
V
O.S
terminal). If they are placed too far from C
4
, abnormal oscillation due to decreased regulation or increased switching ripple may occur.
4) Connect current sensing terminal C.S and GND as closely as possible to the detection resistor Rs (a current of approximately 0.5mA flows
from the CS terminal).
If they are placed too far from Rs, a decrease of the overcurrent setting point due to the voltage drop in the pattern, or malfunction of the
protection circuit due to increased ringing may occur.
I
T
a
-P
D
Characteristics
STR7000 Series
STR7100 Series
3
2
9
4
V
IN
C
1
C
5
330P
*
C
2
330p
C
3
10
μ
F
2200
μ
F
C
4
1500
μ
F
×
2 (parallel)
V
O
GND
*
C
5
STR7100 Series only
1
2
5
5
1
10
8
6
7
3
4
V
IN
GND
F/W
DRIVE
STR7000
STR7100
SERIES
SW
V
IN
V
O.S
R
S
V
O
. ADJ
OSC. OUT
SHUT DOWN
V
REF
C.S
C.A
C.B
GND
DRIVE
L
6A ... 0.02
5V ... 200
μ
H
12V ...
μ
H
250
μ
H
SI-8020
SERIES
40
35
30
25
20
15
10
5
0
0
25
50
75
100
125
P
D
Ambient Temperature T
a
(
°
C)
200
×
300
×
2
200
×
200
×
2
100
×
200
×
2
100
×
100
×
2
75
×
75
×
2
Without heatsink
Without Mica
With Silicon Grease
Heatsink: Aluminum
Unit: mm
40
35
30
25
20
15
10
5
0
0
25
50
75
100
125
P
D
Ambient Temperature T
a
(
°
C)
200
×
300
×
2
200
×
200
×
2
100
×
200
×
2
100
×
100
×
2
75
×
75
×
2
Without heatsink
Without Mica
With Silicon Grease
Heatsink: Aluminum
Unit: mm
G
STR7000+SI-8020 Series