Datasheet

LT3486
16
3486fe
TYPICAL APPLICATIONS
3486 TA05A
3V TO 5V
C
OUT1
2.2µF
C
OUT2
2.2µF
25mA
PWM2
100Hz
8.06Ω 8.06Ω
25mA
OFF ON
D1
Q1
5V
100k
100k
2.8k
2.8k
63.4k
Q2
D2
C
IN
10µF
L1
10µH
L2
10µH
V
IN
V
IN
4.7nF
4.7nF
8 LEDs 8 LEDs
C
OUT1
, C
OUT2
: 35V, X5R OR X7R
C
IN
: 10V, X5R OR X7R
C
REF
0.1µF
V
C1
V
C2
R
T
SW1 SW2
V
IN
LT3486
OVP2
CTRL2
REF
PWM2
FB2
OVP1
CTRL1
SHDN
PWM1
FB1
PWM1
100Hz
D1, D2: ZETEX ZLLS400
L1, L2: TOKO D53LC (TYPE A)
Q1, Q2: FAIRCHILD 2N7002
1 Li-Ion Cell to 8/8 White LEDs
PWM DUTY CYCLE (%)
0
75
80
85
80
3486 TA05b
70
65
20 40 60 100
60
55
50
25
30
35
20
15
10
5
0
EFFICIENCY (%)
LED CURRENT (mA)
V
IN
= 3.6V
8/8 LEDs
EFFICIENCY
LED CURRENT
LED Current and Efficiency vs PWM Duty Cycle
Wide (250:1) Dimming Range
(LED Current 0.1mA to 25mA)
I
L
200mA/DIV
LED CURRENT
20mA/DIV
PWM
5V/DIV
2ms/DIV
3486 TA05c
V
IN
= 3.6V
CTRL1 = 3.6V
8 LEDs/25mA
PWM FREQ = 100Hz
DUTY CYCLE (%)
0.1
LED CURRENT (mA)
10
100
1 10 100
3486 TA05d
1
0.10
0.01
V
IN
= 3.6V
8/8 LEDs
PWM FREQ = 100Hz
PWM Dimming Waveforms