MIC4681_05 Datasheet, PDF (15/16 Pages) Micrel Semiconductor – 2A-Peak SuperSwitcher SOP-8 Buck Regulator

MIC4681
Applications Circuits*
For continuously updated circuits using the MIC4681, see Application Hint 37 at www.micrel.com.
Micrel
J1
+30V max.
C1
22µF
35V
J3
GND
C2
100nF
OFF
ON
S1
NKK G12AP
U1 MIC4681
2 _IN
SW ³
1 _SHDN
FB ⁴
GND
SOP-8
5–8
D3
1N4148
L1
100µH
D1
MMBR140LT3
C3
220µF
10V
U2
LM4041DIM3-1.2
R6
10k
C5
220nF
R1
0.100Ω
R7
4.99k
C4
10nF
J2
5V ±2%
800mA ±5%
4
R4
16.2k ₃
R5
221k
D2
5
1N4148
U3
2 _MIC6211BM5
R2
3.01k
R3
976Ω
J4
GND
Figure 7. Constant Current and Constant Voltage Battery Charger
J1
+12V
J2
GND
C4
68µF
20V
U1 MIC4681
2 _IN
SW ³
C5
33µF
35V
1 _SHDN
FB ⁴
GND
SOP-8
5–8
L1
33µH
D1
ES1B
1A 100V
C3
0.022µF
50V
R1
8.87k
R2
1k
C1
68µF
20V
Figure 8. +12V to –12V/150mA Buck-Boost Converter
J3
GND
C2
0.1µF
J4
–12V/150mA
+4.5V to +17V
C1
100µF
20V
SHUTDOWN
ENABLE
U2
U1 MIC4681 MIC4417BM4
2 _IN
C6
0.1µF
50V _{1 SHDN}
SW ³
FB ⁴
R1
GND
1k
SOP-8
5–8
1%
Q1
* I_SAT = 7.5A
Si4425DY
L1*
R2
20mΩ
50µH
D1
5A
C2
470µF
6.3V
C3
470µF _{R3 R4}
6.3V _{1k 1k}
1% 1%
R5
16k
1%
Figure 9. 5V to 3.3V/5A Power Supply
C4
1000pF
R6
16k 1%
R7
3.01k
1%
D2
1N4148
U3
R8
MIC6211BM5 1.78k
1%
3.3V/5A
C5
0.1µF
GND
* See Application Hint 37 at www.micrel.com for bills of material.
April 2005
15
MIC4681