LT1618_1 Datasheet, PDF (1/16 Pages) Linear Technology – Constant-Current/Constant-Voltage 1.4MHz Step-Up DC/DC Converter

LT1618
Constant-Current/
Constant-Voltage 1.4MHz
Step-Up DC/DC Converter
FEATURES
■ _{Accurate Input/Output Current Control: ±5% Over}
Temperature
■ _{Accurate Output Voltage Control: ±1%}
■ _{Wide VIN Range: 1.6V to 18V}
■ _{1.4MHz Switching Frequency}
■ _{High Output Voltage: Up to 35V}
■ _{Low VCESAT Switch: 200mV at 1A}
■ _{Available in (3mm × 3mm × 0.8mm) 10-Pin DFN and}
10-Pin MSOP Packages
U
APPLICATIO S
■ _{LED Backlight Drivers}
■ _{USB Powered Boost/SEPIC Converters}
■ _{Input Current Limited Boost/SEPIC Converters}
■ _{Battery Chargers}
DESCRIPTIO
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.
TYPICAL APPLICATIO
USB to 12V Boost Converter
(with Selectable 100mA/500mA Input Current Limit)
V_IN
5V
C1
4.7µF
3.3V
OFF ON
0V
L1
0.1Ω
10µH
D1
2
7
ISN
SW
3
ISP
LT1618
8
1
V_IN
FB
9
SHDN
20k
I_ADJ GND V_C
4 5 10
V_OUT
12V
R1
909k
C2
4.7µF
R2
107k
3.3V
100mA 500mA
0V
2k
13k
10nF
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN EMK316BJ475
D1: ON SEMICONDUCTOR MBR0520
L1: SUMIDA CR43-100
1618 TA01a
Efficiency Curve
90
85
80
75
70
65
60
0 20 40 60 80 100 120 140 160
LOAD CURRENT (mA)
1618 TA01b
sn1618 1618fas
1