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AS1339

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

f .... Switching Frequency (2.0MHz typical)

L .... Inductor Value

Accepting larger values of ripple current allows the use of low inductance values, but results in higher output voltage

ripple, greater core losses, and lower output current capability. The total losses of the coil have a strong impact on the

efficiency of the dc/dc conversion and consist of both the losses in the dc resistance and the following frequency-

dependent components:

1. The losses in the core material (magnetic hysteresis loss, especially at high switching frequencies)

2. Additional losses in the conductor from the skin effect (current displacement at high frequencies)

3. Magnetic field losses of the neighboring windings (proximity effect)

4. Radiation losses

Note:

For highest efficiency, a low DC-resistance inductor is recommended.

Table 8. Recommended Inductors

Part Number

L

DCR

Current Rating Dimensions (L/W/T)

Manufacturer

MLP2520S1R5S

1.5µH

80m

Ω

1.5A

2.5x2.0x1.2mm

TDK

www.tdk.com

MLP2520S2R2S

2.2µH

110m

Ω

1.2A

2.5x2.0x1.2mm

MLP2520S3R3S

3.3µH

110m

Ω

1.0A

2.5x2.0x1.2mm

EPL2014-222MLC

2.2µH

120m

Ω

0.98A

2.2x2.0x1.4mm

Coilcraft

www.coilcraft.com

EPL2014-332MLC

3.3µH

152m

Ω

0.8A

2.2x2.0x1.4mm

EPL2014-472MLC

4.7µH

231m

Ω

0.65A

2.2x2.0x1.4mm

XPL2010-222ML

2.2µH

156m

Ω

1.2A

2.0x1.9x1.0mm

XPL2010-332ML

3.3µH

207m

Ω

0.925A

2.0x1.9x1.0mm

(EQ 3)

ΔI

L

V

OUT

V

IN

V

OUT

–

()

×

V

IN

fL

×

×

------------------------------------------------------

=

(EQ 4)

I

LMAX

I

OUTMAX

ΔI

L

2

--------

+

=