Datasheet

LT3582/LT3582-5/LT3582-12
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Choosing Inductors
Several series of inductors that work well with the LT3582
series are listed in Table 3. This table is not complete, and
there are many other manufacturers and parts that can
be used. Consult each manufacturer for more detailed
information and for their entire selection of related parts,
as many different sizes and shapes are available.
Table 3. Inductor Manufacturers
Coilcraft LPS3008-LPS4018 Series,
XPL2010 Series
www.coilcraft.com
Murata LQH32C, LQH43C Series www.murata.com
Sumida CDRH26D09, CDRH26D11,
CDRH3D14 Series
www.sumida.com
TDK VLF and VLCF Series www.tdk.com
Würth
Elektronik
WE-TPC Series Type T, TH,
XS and S
www.we-online.com
Inductances of 2.2H to 10µH typically result in a good
tradeoff between inductor size and system performance.
More inductance typically yields an increase in effi ciency
at the expense of increased output ripple. Less inductance
may be used in a given application depending on required
effi ciency and output current. For higher effi ciency, choose
inductors with high frequency core material, such as ferrite,
to reduce core losses. Also to improve effi ciency, choose
inductors with more volume for a given inductance. The
inductor should have low DCR (copper-wire resistance)
to reduce I
2
R losses, and must be able to handle the peak
inductor current without saturating. To minimize radiated
noise, use a toroidal or shielded inductor (note that the
inductance of shielded types will drop more as current
increases, and will saturate more easily).
Peak Current Rating: Real inductors can experience a drop
in inductance as current and temperature increase. The
inductors should have saturation current ratings higher
than the peak inductor currents. The peak inductor cur-
rents can be calculated as:
I
PK
≅I
LIMIT
+
V
LSWON
•T
OS
L
mA
where:
I
PK
= Peak inductor current
I
LIMIT
= Typically 350mA for Boost and 600mA
for Inverting
L = Inductance in µH
V
LSWON
= Maximum inductor voltage when the
power switch is “on.” Typically max V
IN
for the Boost and Inverting converters.
T
OS
= 100 for Boost and 125 for Inverting
APPLICATIONS INFORMATION