LT1618
Constant-Current/
Constant-Voltage 1.4MHz
Step-Up DC/DC Converter
FEATURES
■
■
■
■
■
■
■
DESCRIPTIO
Accurate Input/Output Current Control:
±5%
Over
Temperature
Accurate Output Voltage Control:
±1%
Wide V
IN
Range: 1.6V to 18V
1.4MHz Switching Frequency
High Output Voltage: Up to 35V
Low V
CESAT
Switch: 200mV at 1A
Available in (3mm
×
3mm
×
0.8mm) 10-Pin DFN and
10-Pin MSOP Packages
The LT
®
1618 step-up DC/DC converter combines a tradi-
tional voltage feedback loop and a unique current feedback
loop to operate as a constant-current, constant-voltage
source. This fixed frequency, current mode switcher oper-
ates from a wide input voltage range of 1.6V to 18V, and
the high switching frequency of 1.4MHz permits the use of
tiny, low profile inductors and capacitors. The current
sense voltage is set at 50mV and can be adjusted using the
I
ADJ
pin.
Available in the 10-Pin (3mm
×
3mm) Exposed Pad DFN
and 10-pin MSOP packages, the LT1618 provides a com-
plete solution for constant-current applications.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
■
■
■
■
LED Backlight Drivers
USB Powered Boost/SEPIC Converters
Input Current Limited Boost/SEPIC Converters
Battery Chargers
TYPICAL APPLICATIO
USB to 12V Boost Converter
(with Selectable 100mA/500mA Input Current Limit)
V
IN
5V
0.1Ω
L1
10µH
D1
V
OUT
12V
7
SW
LT1618
8
3.3V
OFF ON
0V
20k
9
V
IN
SHDN
I
ADJ
GND
4
3.3V
100mA 500mA
0V
5
V
C
10
2k
13k
10nF
FB
90
85
2
C1
4.7µF
3
ISN
ISP
1
R2
107k
C2
4.7µF
EFFICIENCY (%)
R1
909k
80
75
70
65
60
0
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN EMK316BJ475
D1: ON SEMICONDUCTOR MBR0520
L1: SUMIDA CR43-100
1618 TA01a
U
Efficiency Curve
60 80 100 120 140 160
40
LOAD CURRENT (mA)
1618 TA01b
U
U
sn1618 1618fas
1
LINER [ LINEAR TECHNOLOGY ]
