Datasheet

LT3496
11
3496ff
Table 1. Ceramic Capacitor Manufacturers
VENDOR TYPE SERIES
Taiyo Yuden Ceramic X5R, X7R
AVX Ceramic X5R, X7R
Murata Ceramic X5R, X7R
Kemet Ceramic X5R, X7R
Inductor Selection
Several inductors that work well with the LT3496 are listed
in Table 2. However, there are many other manufacturers
and devices that can be used. Consult each manufacturer
for more detailed information and their entire range of
parts. Ferrite core inductors should be used to obtain the
best efficiency. Choose an inductor that can handle the
necessary peak current without saturating, and ensure that
the inductor has a low DCR (copper-wire resistance) to
minimize I
2
R power losses. An inductor with a magnetic
shield should be used to prevent noise radiation and cross
coupling among the three channels.
Diode Selection
The Schottky diode conducts current during the interval
when the switch is turned off. Select a diode V
R
rated
for the maximum SW voltage. It is not necessary that
the forward current rating of the diode equal the switch
current limit. The average current, I
F
, through the diode
is a function of the switch duty cycle. Select a diode with
forward current rating of:
I
F
= I
L
• (1 – D)
where I
L
is the inductor current.
If using the PWM feature for dimming, it is important to
consider diode leakage, which increases with the tem-
perature from the output during the PWM low interval.
Therefore, choose the Schottky diode with sufficient low
leakage current. Table 3 shows several Schottky diodes
that work well with the LT3496.
Table 3. Schottky Diodes
PART NUMBER V
R
(V) I
F
(A) PACKAGE
ZETEX
ZLLS350 40 0.38 SOD523
ZLLS400 40 0.52 SOD323
applications inForMation
Table 2. Surface Mount Inductors
PART NUMBER
VALUE
(µH)
DCR
(Ω MAX) I
RMS
(A)
SIZE
W × L × H (mm3)
Sumida
CMD4D06 2.2 0.116 0.95
3.5 × 4.3 × 0.8
3.3 0.174 0.77
CDRH3D16 2.2 0.072 1.20
3.8 × 3.8 × 1.8
3.3 0.085 1.10
4.7 0.105 0.90
CDRH4D28 10 0.128 1.00
5.0 × 5.0 × 3.0
15 0.149 0.76
CDRH5D28 22 0.122 0.9
6.0 × 6.0 × 3.0
33 0.189 0.75
CooperET
SD3112 2.2 0.140 0.97
3.1 × 3.1 × 1.2
3.3 0.165 0.90
4.7 0.246 0.74
SD14 10 0.2058 1.1
5.0 × 5.0 × 1.4
SD20 15 0.1655 1.25
5.0 × 5.0 × 2.0
22 0.2053 1.12
SD25 33 0.2149 1.11
5.0 × 5.0 × 2.5
Taiyo Yuden
NR3015 2.2 0.06 1.48
3.0 × 3.0 × 1.5
4.7 0.12 1.02
NP04SZB 4.7 0.075 1.6
4.0 × 4.0 × 1.8
10 0.100 1.2
15 0.180 0.95
22 0.210 0.77