lt3593 Linear Technology Corporation, lt3593 Datasheet - Page 8

• Manufacturer Part Number: lt3593
• Description: 1mhz White Led Driver With Output Disconnect And One Pin Current Programming
• Manufacturer: Linear Technology Corporation

APPLICATIONS INFORMATION
LT3593
Inductor Selection
A 10μH inductor is recommended for most LT3593 ap-
plications. Although small size and high effi ciency are
major concerns, the inductor should have low core losses
at 1MHz and low DCR (copper wire resistance). Some
inductors in this category with small size are listed in
Table 1. The effi ciency comparison of different inductors
is shown in Figure 4.
Table 1. Recommended Inductors
PART
LQH43CN100
LQH32CN100
NR3010T100M
VLF4012AT-100M
VLF3010AT-100M
DE2812-1098AS-100M
DB3015C-1068AS-100M
Capacitor Selection
The small size of ceramic capacitors makes them ideal
for LT3593 applications. Use only X5R and X7R types
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 1μF output capacitor are
suffi cient for most applications.
8
Figure 4. Effi ciency Comparison of Different Inductors
90.00
80.00
70.00
60.00
50.00
40.00
30.00
0.00
(μH)
5.00
10
10
10
10
10
10
10
L
LED CURRENT (mA)
DCR
0.24
0.44
0.45
0.20
0.58
0.29
0.38
(Ω)
NR3010T100M
VLF4012-AT-100MR50
LQH43CN100K03
VLF3010AT-100MR49
LQH32CN100K53
DB3015C-1068AS-100M
10.00
CURRENT
RATING
15.00
(mA)
650
450
500
500
490
580
400
3593 F04
20.00
VENDOR
Murata
Taiyo Yuden
TDK
TOKO
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
Diode Selection
Schottky diodes, with their low forward voltage drop and
fast reverse recovery, are the ideal choices for LT3593 ap-
plications. The forward voltage drop of a Schottky diode
represents the conduction losses in the diode, while the
diode capacitance (C
losses. For diode selection, both forward voltage drop and
diode capacitance need to be considered. Schottky diodes
with higher current ratings usually have lower forward
voltage drop and larger diode capacitance, which can
cause signifi cant switching losses at the 1.0MHz switching
frequency of the LT3593. A Schottky diode rated at 400mA
to 500mA is suffi cient for most LT3593 applications. Some
recommended Schottky diodes are listed in Table 3.
Table 3. Recommended Schottky Diodes
PART
NUMBER
CMDSH05-4
CMMSH1-40
ZLL5400
PMEG-
4005AEA
Taiyo Yuden
FORWARD
CURRENT
Murata
Kemet
AVX
(mA)
1000
500
520
500
VOLTAGE
500mA
400mA
500mA
0.47 at
0.55 at
0.50 at
0.47 at
DROP
T
(V)
1A
or C
CAPACITANCE
D
) represents the switching
15 at 30V
50 at 1V
80 at 4V
50 at 1V
DIODE
(pF)
www.t-yuden.com
www.avxcorp.com
www.murata.com
www.kemet.com
[phone]
[phone]
[phone]
[phone]
MANUFACTURER
Central
631-435-1110
www.centralsemi.com
Zetex
631-543-7100
www.zetex.com
Phillips
[phone]
www.semiconductors.
phillips.com
3593f