lt3497eddb-trpbf Linear Technology Corporation, lt3497eddb-trpbf Datasheet - Page 14

• Manufacturer Part Number: lt3497eddb-trpbf
• Description: Dual Full Function White Led Driver With Integrated Schottky Diodes
• Manufacturer: Linear Technology Corporation

LT3497
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
APPLICATIONS INFORMATION
TYPICAL APPLICATIONS
14
R
SENSE1
1µF
C1
10Ω
AND DIMMING
C1, C2: TAIYO YUDEN GMK212BJ105KG
C3: TAIYO YUDEN LMK212BJ105MG
L1, L2: MURATA LQH32CN100K53
Li-Ion to 1/2 White LEDs
SHUTDOWN
OFF ON
CONTROL 1
10µH
L1
CAP1
LED1
CTRL1
SW1 V
LT3497
3V TO 5V
GND
IN
V
IN
CTRL2
AND DIMMING
SW2
CAP2
LED2
SHUTDOWN
CONTROL 2
GROUND
L2
10µH
VIA TO
PLANE
OFF ON
Figure 12. Recommended Component Placement
R
10Ω
SENSE2
C2
1µF
C
L2
L1
SW2
SW1
IN
C
GROUND PLANE
OUT1
3497 TA02a
V
IN
VIA TO
GROUND PLANE
CAP2
CAP1
VIAS TO
C3
1µF
10
C
9
8
7
6
OUT2
the switching node. Place the output capacitors (C
and C
The placement of a bypass capacitor on V
in close proximity to the IC to fi 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.
LED2
5
4
3
2
1
LED1
OUT2
) next to the output pins (CAP1 and CAP2).
70
65
60
55
50
45
40
35
30
GND
0
V
1/2LEDs
IN
= 3.6V
Conversion Effi ciency
CTRL2
CTRL1
5
LED CURRENT (mA)
3497 F12
10
15
3497 TA02b
20
IN
needs to be
OUT1
3497f