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AS1331

Datasheet - A p p l i c a t i o n I n f o r m a t i o n

9 Application Information

Component Selection

Only three power components are required to complete the design of the buck-boost converter. For the adjustable

allow the use of low value, low profile inductors and tiny external ceramic capacitors.

Inductor Selection

For best efficiency, choose an inductor with high frequency core material, such as ferrite, to reduce core losses. The

inductor should have low DCR (DC resistance) to reduce the I²R losses, and must be able to handle the peak inductor

current without saturating. A 6.8µH inductor with a >600mA current rating and <400m

Ω DCR is recommended.

Capacitor Selection

The buck-boost convertor requires two capacitors. Ceramic X5R or X7R types will minimize ESL and ESR while

capacitor should be between 10µF and 47µF. A larger output capacitor should be used if lower peak to peak output

capacitors for input and output capacitor selection.

Table 4. Recommended Inductors

Part Number

L

DCR

Current Rating Dimensions (L/W/T)

Manufacturer

LPS3015-682M

6.8µH

300m

Ω

0.89A

3.0x3.0x1.5mm

Coilcraft

www.coilcraft.com

EPL2014-682M

6.8µH

287m

Ω

0.80A

2.0x2.0x1.4mm

XPL2010-682M

6.8µH

336m

Ω

0.73A

2.0x1.9x1.0mm

Table 5. Recommended Input Capacitor

Part Number

C

TC Code

Rated Voltage

Dimensions (L/W/T)

Manufacturer

GRM188R61A225KE34

2.2µF

X5R

10V

0603, T=0.87mm

Murata

www.murata.com

GRM188R60J475KE19

4.7µF

X5R

6.3V

0603, T=0.87mm

GRM219R60J106KE19

10µF

X5R

6.3V

0805, T=0.95mm

Table 6. Recommended Output Capacitor

Part Number

C

TC Code

Rated Voltage

Dimensions (L/W/T)

Manufacturer

GRM21BR61A106KE19

10µF

X5R

10V

0805, T=1.35mm

Murata

www.murata.com

GRM319R61A106KE19

10µF

X5R

10V

1206, T=0.95mm

GRM319R61A106KE19

10µF

X5R

10V

1210, T=0.95mm

GRM31CR61C226KE15

22µF

X5R

16V

1206, T=1.8mm

GRM31CR60J475ME19

47µF

X5R

6.3V

1206, T=1.75mm