LT3465_15 Datasheet, PDF (8/16 Pages) Linear Technology – 1.2MHz/2.4MHz White LED Drivers with Built-in Schottky in ThinSOT

LT3465/LT3465A
APPLICATIO S I FOR ATIO
skipping using a 1k resistor from FB to GND. The photo
in Figure 3b details circuit operation driving three white
LEDs at a 0.2mA load. Peak inductor current is less
than 30mA.
Inductor Selection
A 22µH inductor is recommended for most LT3465 appli-
cations. Although small size and high efficiency are major
concerns, the inductor should have low core losses at
1.2MHz and low DCR (copper wire resistance). Some
inductors in this category with small size are listed in
Table 1. The efficiency comparison of different inductors
is shown in Figure 4a. A 22µH or 10µH inductor is recom-
mended for most LT3465A applications. The inductor
should have low core losses at 2.4MHz and low DCR. The
efficiency comparison of different inductors is shown in
figure 4b.
Table 1. Recommended Inductors
PART
NUMBER
CURRENT RATING
DCR (Ω)
(mA)
LQH32CN220
0.71
250
LQH2MCN220
2.4
185
ELJPC220KF
4.0
160
CDRH3D16-220 0.53
350
LB2012B220M 1.7
75
LEM2520-220
5.5
125
MANUFACTURER
Murata
814-237-1431
www.murata.com
Panasonic
714-373-7334
www.panasonic.com
Sumida
847-956-0666
www.sumida.com
Taiyo Yuden
408-573-4150
www.t-yuden.com
Taiyo Yuden
408-573-4150
www.t-yuden.com
85
V_IN = 3.6V
4 LEDs
80
75
70
65
60
MURATA LQH32CN220
55
TAIYO YUDEN LB2012B220M
TAIYO YUDEN CB2012B220
50
0
5
10
15
20
LED CURRENT (mA)
3465A F04b
Figure 4a. Efficiency Comparison of Different Inductors (LT3465)
80
V_IN = 3.6V
4 LEDs
75
70
65
60
MURATA LQH32CN220
MURATA LQH32CN100
MURATA LQH2MCN220
55
TOKO D312-220
TOKO D312-100
TAIYO YUDEN LB2012B220
50
0
5
10
15
20
LED CURRENT (mA)
3465A F04b
Figure 4b. Efficiency Comparison of Different Inductors (LT3465A)
Capacitor Selection
The small size of ceramic capacitors makes them ideal for
LT3465 and LT3465A applications. X5R and X7R types are
recommended 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 0.22µF
output capacitor are sufficient for most LT3465 and
LT3465A applications.
Table 2. Recommended Ceramic Capacitor Manufacturers
MANUFACTURER
PHONE
URL
Taiyo Yuden
408-573-4150
www.t-yuden.com
Murata
814-237-1431
www.murata.com
Kemet
408-986-0424
www.kemet.com
3465afa
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