LT3494EDDB#PBF Linear Technology, LT3494EDDB#PBF Datasheet - Page 10

• Manufacturer Part Number: LT3494EDDB#PBF
• Manufacturer: Linear Technology

Specifications of LT3494EDDB#PBF

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Pin Count: 8
• Mounting: Surface Mount
• Package Type: DFN EP
• Case Length: 3mm
• Screening Level: Industrial
• Lead Free Status / RoHS Status: Compliant

LT3494/LT3494A
the CAP pin will improve effi ciency and lower the stress
placed on the internal Schottky diode.
Board Layout Considerations
As with all switching regulators, careful attention must be
paid to the PCB board layout and component placement.
To maximize effi ciency, switch rise and fall times are made
as short as possible. To prevent electromagnetic interfer-
ence (EMI) problems, proper layout of the high frequency
switching path is essential. The voltage signal of the SW pin
has sharp rising and falling edges. Minimize the length and
area of all traces connected to the SW pin and always use
a ground plane under the switching regulator to minimize
interplane coupling. In addition, the FB connection for
the feedback resistor R1 should be tied directly from the
Vout pin to the FB pin and be kept as short as possible,
ensuring a clean, noise-free connection. Recommended
component placement is shown in Figure 4.
TYPICAL APPLICATIONS
APPLICATIONS INFORMATION
10
Figure 5. One Li-Ion Cell Input Boost Converter with the LT3494
V
3V TO 4.2V
25
24
23
22
21
20
19
18
17
16
15
OUT
V
IN
V
C1, C2: X5R OR X7R WITH SUFFICIENT VOLTAGE RATING
C3: MURATA GRM31MR71E225K
L1: MURATA LQH32CN150K53
R1 VALUE REQUIRED
OUT
TURN ON/OFF
DIMMING
C2
4.7μF
(MΩ)
3.57
3.40
3.24
3.09
2.94
2.80
2.67
2.49
2.37
2.21
2.05
15μH
L1
3
5
4
V
SHDN
CTRL
SW
CC
1
LT3494
MAXIMUM OUTPUT CURRENT AT
V
CAP
GND
OUT
FB
8
7
6
2
3V INPUT (mA)
R1
3494 F05
C1
0.22μF
10.0
10.6
11.3
12.1
12.9
13.6
14.8
16.0
17.2
8.6
9.3
C3
2.2μF
V
OUT
90
80
50
40
30
20
70
60
0.1
V
Figure 4. Recommended Layout
IN
VIAS TO GROUND PLANE REQUIRED
TO IMPROVE THERMAL PERFORMANCE
= 3.6V
3.6V to 16V Effi ciency
CTRL
LOAD CURRENT (mA)
1
SW
GND
V
CTRL
CC
LOAD FROM
CAPACITOR
LOAD FROM
V
GND
GND
OUT
10
SHDN
V
CAP
OUT
FB
3494 TA01c
SHDN
100
280
240
200
160
120
80
40
0
3494 F04
3494fb