LT3590
APPLICATIONS INFORMATION
Inductor Selection
Capacitor Selection
A 220μH inductor is recommended for most LT3590 ap-
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 sufficient 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.
plications with V < 25V and 470μH is recommended for
IN
applications with V > 25V. Although small size and high
IN
efficiency 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 efficiency
comparison of different inductors is shown in Figure 3.
Table 1. Inductor Manufacturers
INDUCTANCE
RANGE (μH)
(RELEVANT TO
THIS PART)
Table 2 shows a list of several ceramic capacitor manufac-
turers. Consultthemanufacturersfordetailedinformation
on their entire selection of ceramic parts.
PART
SERIES
DIMENSIONS
(mm)
VENDOR
Coilcraft
DO1605
LPS4012
LPS3010
1812FS
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
www.coilcraft.com
Table 2: Recommended Ceramic Capacitor Manufacturers
Taiyo Yuden
(408) 573-4150
www.t-yuden.com
MSS5131
5.1 × 5.1 × 3.1
4.8 × 4.8 × 2.0
Sumida
www.sumida.com
CDC4D20
100 TO 680
AVX
(803) 448-9411
www.avxcorp.com
Murata
Kemet
(714) 852-2001
Toko
LLQ1608
LLQ2012
100 TO 270
100 TO 680
www.murata.com
www.tokoam.com
(408) 986-0424
www.kemet.com
Würth Elektronik
www.we-online.com
WE-PD2
TYPE M
WE-PD2
TYPE L
100 TO 220
5.2 × 5.8 × 4.5
7.0 × 7.8 × 5.0
100 to 470
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
92
TDK SLF70145-471MR22-PF
V
= 48V
IN
MURATA QH32CN471K23
MURATA LQH43CN471K03
COILCRAFT LP06013-474KLB
COILCRAFT 1008PS-474KLB
COILCRAFT LPS4012-474ML
10 LEDs
FRONT PAGE
APPLICATION
CIRCUIT
90
88
86
84
40
50
0
10
20
30
LED CURRENT (mA)
3590 F03
Figure 3. Efficiency Comparison of Different Inductors
3590f
8
Linear [ Linear ]
