Datasheet

12
LT1937
1937f
PART NUMBER DESCRIPTION COMMENTS
LT1615 Micropower Step-Up Converter in ThinSOT Up to 36V Output; 20µA I
Q
, V
IN
: 1V to 15V,
Can Drive Up to Six LEDs, ThinSOT Package
LT1618 Constant Current/Voltage Step-Up DC/DC 1.4MHz, Drives Up to 20 LEDs, MS10 Package
LT1932 White LED Step-Up Converter in ThinSOT 1.2MHz, V
IN
= 1V to 10V, Drives Up to Eight LEDs from 3V Input,
ThinSOT Package
LT1944/LT1944-1 Dual Micropower Step-Up Converter V
IN
= 1.2V to 15V, Two Independent DC/DCs, Up to 36V
OUT
, 20µA I
Q
,
MS10 Package
LTC
®
3200/LTC3200-5 Low Noise White LED Charge Pump Converter 2MHz, 100mA, No Inductor Required, MS8/ThinSOT Packages
For up to 6 LEDs
LTC3201 Ultralow Noise White LED Charge Pump Converter 1.8MHz, 100mA, No Inductor Required, DAC Brightness Adj,
For up to 6 LEDs MS8 Package
LTC3202 Low Noise White LED Fractional Charge Pump Converter 1.5MHz, 125mA, No Inductor Required, Digital Brightness Adjust,
For up to 6 LEDs MS8 Package
LT/TP 0702 2K • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2002
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone]
●
FAX: [phone]
●
www.linear.com
Li-Ion to Four White LEDs
Four LED Efficiency
V
IN
SW
LT1937
L
22µH
C
OUT
0.22µF
C
IN
1µF
C
IN
: TAIYO YUDEN JMK107BJ105
C
OUT
: AVX 0603YD224
D: CENTRAL CMDSH-3
L: MURATA LQH3C220
1937 TA02a
V
IN
3V TO 5V
SHDN
R1
4Ω
5k
90k
FB
D
V
DC
DIMMING
GND
LOAD CURRENT (mA)
0
60
EFFICIENCY (%)
70
75
80
85
510
1937 TA02b
15 20
V
IN
= 3V
V
IN
= 3.6V
U
TYPICAL APPLICATIO
RELATED PARTS
0.2µs/DIV
1937 TA02c
V
SW
10V/DIV
I
SW
100mA/DIV
V
OUT
100mV/DIV
V
IN
= 3.6V
FOUR LEDs
15mA
Switching Waveforms