LT3496IFE(RevE) Просмотр технического описания (PDF) - Linear Technology

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Компоненты Описание

производитель

LT3496IFE
(Rev.:RevE)

Triple Output LED Driver

Linear Technology 

LT3496

APPLICATIONS INFORMATION

Table 1. Ceramic Capacitor Manufacturers

VENDOR

TYPE

Taiyo Yuden

Ceramic

AVX

Ceramic

Murata

Ceramic

Kemet

Ceramic

SERIES

X5R, X7R

X5R, X7R

X5R, X7R

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 I2R 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 VR 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, IF, through the diode

is a function of the switch duty cycle. Select a diode with

forward current rating of:

IF = IL • (1 – D)

where IL 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 2. Surface Mount Inductors

VALUE DCR

PART NUMBER (μH) (Ω MAX)

Sumida

CMD4D06

2.2

0.116

3.3

0.174

CDRH3D16

2.2

0.072

3.3

0.085

4.7

0.105

CDRH4D28

10

0.128

15

0.149

CDRH5D28

22

0.122

33

0.189

CooperET

SD3112

2.2

0.140

3.3

0.165

4.7

0.246

SD14

10

0.2058

SD20

15

0.1655

22

0.2053

SD25

33

0.2149

Tayio Yuden

NR3015

2.2

0.06

4.7

0.12

NP04SZB

4.7

0.075

10

0.100

15

0.180

22

0.210

IRMS (A)

0.95

0.77

1.20

1.10

0.90

1.00

0.76

0.9

0.75

0.97

0.90

0.74

1.1

1.25

1.12

1.11

1.48

1.02

1.6

1.2

0.95

0.77

SIZE

W × L × H (mm3)

3.5 × 4.3 × 0.8

3.8 × 3.8 × 1.8

5.0 × 5.0 × 3.0

6.0 × 6.0 × 3.0

3.1 × 3.1 × 1.2

5.0 × 5.0 × 1.4

5.0 × 5.0 × 2.0

5.0 × 5.0 × 2.5

3.0 × 3.0 × 1.5

4.0 × 4.0 × 1.8

Table 3. Schottky Diodes

PART NUMBER

ZETEX

VR (V)

ZLLS350

40

ZLLS400

40

IF (A)

0.38

0.52

PACKAGE

SOD523

SOD323

3496fe

11

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