MIC4685

Micrel

MIC4685

12

September 2002

V

OUT

I

R2

V

IN

C1

D1

D2

L1

C4

5.0V

2.1A

3.01k

976

Ω

7.5V–16V

47

µF, 20V

3A, 30V

1A, 20V

39

µH

330

µF, 6.3V

Vishay-Dale

Schottky

Schottky

Sumida

Vishay-Dale

595D476X0020D2T

B330A

MBRX120 CDRH127R-390MC 594D337X06R3D2T

3.3V

2.2A

3.01k

1.78k

6.0V–16V

47

µF, 20V

3A, 30V

1A, 20V

39

µH

330

µF, 6.3V

Vishay-Dale

Schottky

Schottky

Sumida

Vishay-Dale

595D476X0020D2T

B330A

MBRX120 CDRH127R-390MC 594D337X06R3D2T

2.5V

2.0A

3.01k

2.94k

5.0V–16V

47

µF, 20V

3A, 30V

1A, 20V

39

µH

330

µF, 6.3V

Vishay-Dale

Schottky

Schottky

Sumida

Vishay-Dale

595D476X0020D2T

B330A

MBRX120 CDRH127R-390MC 594D337X06R3D2T

1.8V

2.0A

3.01k

6.49k

5.0V–16V

47

µF, 20V

3A, 30V

1A, 20V

39

µH

330

µF, 6.3V

Vishay-Dale

Schottky

Schottky

Sumida

Vishay-Dale

595D476X0020D2T

B330A

MBRX120 CDRH127R-390MC 594D337X06R3D2T

*

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

Table 1. Recommended Components for Common Ouput Voltages

Recommended Components for a Given Output Voltage (Bootstrap Configuration)

SW

L1

39

µH

IN

FB

GND

EN

D1

B330A

or

SS33

J2

J4

GND

U1 MIC4685BR

C2

0.1

µF

50V

C1

47

µF

20V

J1

D2

MBRX120

1A/20V

J3

GND

JP3

4, Tab

3

BS

1

6

2

5

ON

OFF

C5

330

µF

6.3V

C4*

optional

C7

0.1

µF

50V

C3

0.33

µF

50V

R1

R2

* C4 can be used to provide additional stability

and improved transient response.

Figure 3. Schematic Diagram