Micrel, Inc.

MIC4685

January 2010

13

M9999-012610

Recommended Components for a Given Output Voltage (Bootstrap Configuration)

R1

R2

C1

D1

D2

L1

C4

5.0V

2.1A

3.01k

976Ω

7.5V – 16V

47µF, 20V

Vishay-Dale

595D476X0020D2T

3A, 30V

Schottky

+ Vishay

B330A

1A, 20V

Schottky

B120-E3

39µH

Sumida

CDRH127R-390MC

330µF, 6.3V

Vishay-Dale

594D337X06R3D2T

3.3V

2.2A

3.01k

1.78k

6.0V – 16V

47µF, 20V

Vishay-Dale

595D476X0020D2T

3A, 30V

Schottky

B330A

1A, 20V

Schottky

B120-E3

39µH

Sumida

CDRH127R-390MC

330µF, 6.3V

Vishay-Dale

594D337X06R3D2T

2.5V

2.0A

3.01k

2.94k

5.0V – 16V

47µF, 20V

Vishay-Dale

595D476X0020D2T

3A, 30V

Schottky

B330A

1A, 20V

Schottky

B120-E3

39µH

Sumida

CDRH127R-390MC

330µF, 6.3V

Vishay-Dale

594D337X06R3D2T

1.8V

2.0A

3.01k

6.49k

5.0V – 16V

47µF, 20V

Vishay-Dale

595D476X0020D2T

3A, 30V

Schottky

+ Vishay

B330A

1A, 20V

Schottky

B120-E3

39µH

Sumida

CDRH127R-390MC

330µF, 6.3V

Vishay-Dale

594D337X06R3D2T

*

Maximum output current at minimum input voltage. See SOA curves for maximum output current vs. Input voltage.

Table 1. Recommended Components for Common Output Voltages

SW

L1

39µH

IN

FB

GND

EN

D1

B330A

or

SS33

J2

J4

GND

U1 MIC4685_R

C2

0.1µF

50V

C1

47µF

20V

J1

D2

MBRX120

1A/20V

J3

GND

JP3

4, Tab

3

BS 1

6

2

5

ON

OFF

C5

330µF

6.3V

C4*

optional

C7

0.1µF

50V

C3

0.33µF

50V

R1

R2

* C4 can be used to provide additional stability

and improved transient response.

Figure 3. Schematic Diagram