LT1937
U
TYPICAL APPLICATIO
Li-Ion to Four White LEDs
L
D
22µH
V
IN
3V TO 5V
C
C
OUT
0.22µF
IN
1µF
V
DC
DIMMING
V
SW
FB
IN
90k
LT1937
SHDN
GND
5k
R1
4Ω
C
C
: TAIYO YUDEN JMK107BJ105
OUT
IN
1937 TA02a
: AVX 0603YD224
D: CENTRAL CMDSH-3
L: MURATA LQH3C220
Four LED Efficiency
85
80
75
70
Switching Waveforms
V
SW
10V/DIV
V
IN
= 3V
V
= 3.6V
IN
I
SW
100mA/DIV
V
OUT
100mV/DIV
1937 TA02c
= 3.6V
0.2µs/DIV
V
IN
FOUR LEDs
15mA
60
0
5
10
15
20
LOAD CURRENT (mA)
1937 TA02b
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
Up to 36V Output; 20µA I , V : 1V to 15V,
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LTC®3200/LTC3200-5 Low Noise White LED Charge Pump Converter
For up to 6 LEDs
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Ultralow Noise White LED Charge Pump Converter
For up to 6 LEDs
1.8MHz, 100mA, No Inductor Required, DAC Brightness Adj,
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LTC3202
Low Noise White LED Fractional Charge Pump Converter
For up to 6 LEDs
1.5MHz, 125mA, No Inductor Required, Digital Brightness Adjust,
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1937f
LT/TP 0702 2K • PRINTED IN USA
12 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
LINEAR TECHNOLOGY CORPORATION 2002
Linear [ Linear ]
