ST1S15

Application information

DocID023280 Rev 4

17/27

8

Application information

8.1

Input and output capacitors

Ceramic capacitors with X5R or X7R dielectric and low ESR should be used. The input

capacitor filters any disturbance present in the input line so to obtain a stable operation.

The output capacitor satisfies the output voltage ripple requirement. The output voltage

Equation 1

where ΔI

capacitors with voltage ratings higher than 1.5 times the maximum input or output voltage

is recommended.

8.2

Inductor

The inductor is the key passive component for switching converters. The internal

In addition to the inductance value, in order to avoid saturation, the maximum saturation

The peak current of the inductor has to be calculated as follows:

Equation 2

The following inductor part numbers from different suppliers have been tested in the

ST1S15 converters.

Table 8: Inductors

Manufacturer

Part numbers

Dimension (mm)

Murata

LQM21PNR47MC0D

2.0 x 1.25 x 0.5

LQM21PNR54MG0D

2.0 x 1.25 x 0.5

LQH32PNR47NN0L

3.2 x 2.7 x 1.55

TDK

MLP2012SR47T

2.0 x 1.25 x 0.5

VLS2010ET-1R0N

2.0 x 2.0 x 1.0

1

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

+

L

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

+

=

I

–

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

+