Micrel, Inc.
MIC4685
Recommended Components for a Given Output Voltage (Standard Configuration)
VOUT
IOUT
*
R1
R2
VIN
C1
D1
L1
C5
5.0V
2.0A
3.01k
976Ω
8V – 30V
33µF, 35V
Vishay-Dale
3A, 40V
Schottky
39µH
Sumida
330µF, 6.3V
Vishay-Dale
595D336X0035R2T B340A-E3 CDRH127-390MC
594D337X06R3D2T
3.3V
2.5V
1.8V
2.4A
3.01k
3.01k
3.01k
1.78k
2.94k
6.49k
8V – 26V
7V – 23V
6V – 16V
33µF, 35V
Vishay-Dale
3A, 40V
Schottky
39µH
Sumida
330µF, 6.3V
Vishay-Dale
594D337X06R3D2T
595D336X0035R2T B340A-E3 CDRH127-390MC
2.35A
2.0A
33µF, 35V
Vishay-Dale
3A, 40V
Schottky
39µH
Sumida
330µF, 6.3V
Vishay-Dale
594D337X06R3D2T
595D336X0035R2T B340A-E3 CDRH127-390MC
33µF, 35V
Vishay-Dale
3A, 40V
Schottky
39µH
Sumida
330µF, 6.3V
Vishay-Dale
595D336X0035R2T + Vishay
B340A-E3
CDRH127-390MC
594D337X06R3D2T
*
Maximum output current at minimum input voltage. See SOA curves for maximum output current vs. Input voltage.
Table 2. Recommended Components for Common Output Voltages
D2***
B340
JP3
J1
VIN
J2
VOUT
2A
L1
39µH
U1 MIC4685_R
(34V transient)
2
5
6
IN
SW
C3
0.33µF
50V
1
3
C2
0.1µF
50V
BS
FB
C4*
R1
optional
C1
33µF
35V
J3
GND
3.01k
ON
EN
C5
330µF
6.3V
C7
0.1µF
50V
OFF
D1
B340A
R2
6.49k
R3
2.94k
R4
1.78k
R5
C6**
GND
4, Tab
976W
1
2
3
5
7
JP1a
1.8V
JP1b
2.5V
JP1c
3.3V
JP1d
5.0V
J4
GND
8
4
6
* C4 can be used to provide additional stability
and improved transient response.
Note: optimized for 5VOUT
** C6 Optional
*** D2 is not used for standard configuration and JP3 is open.
Figure 4. Evaluation Board Schematic Diagram
M9999-012610
January 2010
14
MICREL [ MICREL SEMICONDUCTOR ]
