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| LT3497 Datasheet, PDF (14/20 Pages) Linear Integrated Systems – Dual Full Function White LED Driver with Integrated Schottky Diodes | |||
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LT3497
APPLICATIONS INFORMATION
BOARD LAYOUT CONSIDERATIONS
As with all switching regulators, careful attention must be
paid to the PCB board layout and component placement.
To prevent electromagnetic interference (EMI) problems,
proper layout of high frequency switching paths is essential.
Minimize the length and area of all traces connected to
the switching node pins (SW1 and SW2). Keep the sense
voltage pins (CAP1, CAP2, LED1 and LED2) away from
the switching node. Place the output capacitors (COUT1
and COUT2) next to the output pins (CAP1 and CAP2).
The placement of a bypass capacitor on VIN needs to be
in close proximity to the IC to ï¬lter EMI noise from SW1
and SW2. Always use a ground plane under the switching
regulator to minimize interplane coupling. Recommended
component placement is shown in Figure 12.
VIA TO
GROUND PLANE
VIA TO
GROUND
PLANE
SW2
L2
COUT2
CAP2
10
CIN
9
VIN
8
7
L1
6
CAP1
SW1
COUT1
LED2
5
4
3
2
1
LED1
CTRL2
GND
CTRL1
3497 F12
VIAS TO
GROUND PLANE
Figure 12. Recommended Component Placement
TYPICAL APPLICATIONS
Li-Ion to 1/2 White LEDs
VIN
3V TO 5V
C3
C1
C2
1µF
1µF
L1
L2
1µF
10µH
10µH
RSENSE1
10â¦
SW1 VIN SW2
CAP1
CAP2
LT3497
LED1
LED2
CTRL1 GND CTRL2
RSENSE2
10â¦
3497 TA02a
OFF ON
OFF ON
SHUTDOWN
AND DIMMING
CONTROL 1
SHUTDOWN
AND DIMMING
CONTROL 2
C1, C2: TAIYO YUDEN GMK212BJ105KG
C3: TAIYO YUDEN LMK212BJ105MG
L1, L2: MURATA LQH32CN100K53
14
Conversion Efï¬ciency
70
VIN = 3.6V
65 1/2LEDs
60
55
50
45
40
35
30
0
5
10
15
20
LED CURRENT (mA)
3497 TA02b
3497f
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