Datasheet

LT3590
8
3590f
Inductor Selection
A 220μH inductor is recommended for most LT3590 ap-
plications with V
IN
< 25V and 470μH is recommended for
applications with V
IN
> 25V. Although small size and high
effi ciency are major concerns, the inductor should have
low core losses at 850kHz and low DCR (copper wire
resistance). Several manufacturers and inductor series
that meet these criteria are listed in Table 1. The effi ciency
comparison of different inductors is shown in Figure 3.
Table 1. Inductor Manufacturers
VENDOR
PART
SERIES
INDUCTANCE
RANGE (μH)
(RELEVANT TO
THIS PART)
DIMENSIONS
(mm)
Coilcraft
www.coilcraft.com
DO1605
LPS4012
LPS3010
1812FS
MSS5131
100 TO 680
100 TO 680
100 TO 330
100 TO 680
100 TO 390
5.4 × 4.2 × 1.8
4.0 × 4.0 × 1.2
3.0 × 3.0 × 0.9
5.1 × 5.1 × 3.1
Sumida
www.sumida.com
CDC4D20 100 TO 680 4.8 × 4.8 × 2.0
Toko
www.tokoam.com
LLQ1608
LLQ2012
100 TO 270
100 TO 680
Würth Elektronik
www.we-online.com
WE-PD2
TYPE M
WE-PD2
TYPE L
100 TO 220
100 to 470
5.2 × 5.8 × 4.5
7.0 × 7.8 × 5.0
Coiltronics
www.cooperet.com
CTX32C 100 to 330 2.5 × 3.2 × 2.2
Murata
www.murata.com
LQH32M
LQH43M
100 to 560
100 to 680
3.2 × 2.5 × 2.0
4.5 × 3.2 × 2.0
APPLICATIONS INFORMATION
Figure 3. Effi ciency Comparison of Different Inductors
Capacitor Selection
The small size of ceramic capacitors make them ideal
for LT3590 applications. X5R and X7R types are recom-
mended because they retain their capacitance over wider
voltage and temperature ranges than other types such as
Y5V or Z5U. A 1μF input capacitor and a 0.1μF regulator
capacitor are suffi cient for most applications. For the
output capacitor, 1μF is generally recommended, but if
the voltage across the capacitor exceeds 10V, a 0.47μF
capacitor may be used instead. For applications driving
one or two LEDs a 2.2μF output capacitor is needed.
Table 2 shows a list of several ceramic capacitor manufac-
turers. Consult the manufacturers for detailed information
on their entire selection of ceramic parts.
Table 2: Recommended Ceramic Capacitor Manufacturers
Taiyo Yuden [phone]
www.t-yuden.com
AVX [phone]
www.avxcorp.com
Murata [phone]
www.murata.com
Kemet [phone]
www.kemet.com
LED CURRENT (mA)
0
92
90
88
86
84
30
10 20
40 50
EFFICIENCY (%)
3590 F03
TDK SLF70145-471MR22-PF
MURATA QH32CN471K23
MURATA LQH43CN471K03
COILCRAFT LP06013-474KLB
COILCRAFT 1008PS-474KLB
COILCRAFT LPS4012-474ML
V
IN
= 48V
10 LEDs
FRONT PAGE
APPLICATION
CIRCUIT