MIC4680 Micrel Semiconductor, MIC4680 Datasheet - Page 10

• Manufacturer Part Number: MIC4680
• Description: 1A 200kHz SuperSwitcher Buck Regulator Final Information
• Manufacturer: Micrel Semiconductor

MIC4680
Applications Information
Adjustable Regulators
Adjustable regulators require a 1.23V feedback signal. Rec-
ommended voltage-divider resistor values for common out-
put voltages are included in Figure 1b.
For other voltages, the resistor values can be determined
using the following formulas:
MIC4680
*
* *
*
V
1
2
3
5
6
* *
O
8 .
5 .
3 .
0 .
0 .
A
s
V
U
h
l l
V
V
V
V
V
s i
e i
T
e r
h
d l
R1 R2
V
V
a
s
e
- y
s i
OUT
REF
3
3
3
3
3
d
R
o t
D
0 .
0 .
0 .
0 .
0 .
m
o i
* 1
s r
1
1
1
1
1
a
d
k
k
k
k
k
1
g
, e
%
n
e
n I
1.23V
6
2
1
9
7
V
i t
R
. c
s c
4 .
9 .
7 .
7
8
REF
V
V
* 2
6
7
8 (
OUT
9
4
8
REF
f
r o
k
k
k
0
) 5
o l
A
w
4
R2
R1
4
V
R
6
1
X
4 -
I F
Figure 1b. Recommended Components for Common Ouput Voltages
8
T
a
0
1
p
0
P
p
1
S
c i l
5
E
t a
µ
C
1
o i
F
5
N I
n
3
6
s
5
0
V
3
5
R
0
2
0
0
S
B
S
2
2
6
6
0
A
2
G
A
e
V
n
6
s i
r e
0
h
V
l a
a
D
r o
- y
S
1
S
D
c
e
10
h
o i
m
o
d
t t
c i
, e
y k
o
SHUTDOWN
n
n I
ENABLE
d
c
u
* .
t c
* *
r o
Figure 1a. Adjustable Regulator Circuit
S
S
V
IN
u
u
C
m
m
C
IN
d i
d i
o
t l i
a
a
o r
C
C
6
2
1
i n
D
D
8
IN
SHDN
µ
R
R
s c
H
MIC4680BM
L
r o
r o
H
H
1
U
1
1
1
GND
5 .
P
2
2
5
4
2
A
5–8
6 -
6 -
B
6 -
8
8
0
0
SW
8
FB
M
M
0
C
C
3
4
* *
* *
A
D1
V
X
L1
T
P
2
S
2
0
E
C
µ
2
O
F
2
R1
R2
U
7
T
1
June 2000
0
0
1
V
0
R
Micrel
0
0
V
C
6
OUT
OUT
0