LT1617/LT1617-1
Micropower Inverting
DC/DC Converters
in SOT-23
FEATURES DESCRIPTIO
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Low Quiescent Current: The LT 1617/LT1617-1 are micropower inverting DC/DC
20m A in Active Mode converters in a 5-lead SOT-23 package. The LT1617 is
<1m A in Shutdown Mode designed for higher power systems with a 350mA current
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Operates with V as Low as 1V limit and an input voltage range of 1.2V to 15V, whereas
IN
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Low V Switch: 250mV at 300mA the LT1617-1 is intended for lower power and single-cell
CESAT
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Uses Small Surface Mount Components applications with a 100mA current limit and an extended
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High Output Voltage: Up to 34V input voltage range of 1V to 15V. Otherwise, the two
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Tiny 5-Lead SOT-23 Package devices are functionally equivalent. Both devices feature a
quiescent current of only 20m A at no load, which further
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reduces to 0.5m A in shutdown. A current limited, fixed off-
APPLICATIO S
time control scheme conserves operating current, result-
ing in high efficiency over a broad range of load current.
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LCD Bias
The 36V switch allows high voltage outputs up to 34V to
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Handheld Computers
be easily generated without the use of costly transformers.
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Battery Backup
The LT1617s low off-time of 400ns permits the use of
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Digital Cameras
tiny, low profile inductors and capacitors to minimize
footprint and cost in space-conscious portable applications.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
1-Cell Li-Ion to 15V Inverting Converter Efficiency
C3 80
L1 L2
0.22F
22H 22H
V 15V
IN
V = 4.2V
75
IN
2.5V TO 4.2V 12mA
5 1
V SW 70
IN
D1 267k V = 2.5V
IN
C2
LT1617
65
4.7F
43
SHDN NFB
GND
C1
60
24.9k
4.7F
2
55
C1: TAIYO YUDEN LMK316BJ475
1617/-1 TA01
C2: TAIYO YUDEN EMK316BJ475
50
C3: TAIYO YUDEN TMK316BJ224
0.1 1 10 30
L1, L2: MURATA LQH3C220K34
LOAD CURRENT (mA)
D1: MOTOROLA MBR0530
1617/-1 TA01a
1
EFFICIENCY (%)
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ULT1617/LT1617-1
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ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
TOP VIEW
V , SHDN Voltage ................................................... 15V NUMBER
IN
SW Voltage .............................................................. 36V
SW 1 5 V
IN
LT1617ES5
GND 2
NFB Voltage ............................................................. 3V
LT1617ES5-1
NFB 3 4 SHDN
Current into NFB Pin ............................................. 1mA
Junction Temperature........................................... 125 C
S5 PACKAGE
S5 PART MARKING
5-LEAD PLASTIC SOT-23
Operating Temperature Range (Note 2) .. 40 C to 85 C
T = 125 C, q = 256 C/W
JMAX JA LTKF
Storage Temperature Range ................. 65 C to 150 C
LTKA
Lead Temperature (Soldering, 10 sec).................. 300 C
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25 C. V = 1.2V, V = 1.2V unless otherwise noted.
A IN SHDN
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Input Voltage LT1617-1 1.0 V
LT1617 1.2 V
Quiescent Current Not Switching 20 30 m A
V = 0V 1 m A
SHDN
FB Comparator Trip Point l 1.205 1.23 1.255 V
FB Comparator Hysteresis 8mV
Output Voltage Line Regulation 1.2V < V < 12V 0.05 0.1 %/V
IN
FB Pin Bias Current (Note 3) V = 1.23V l 1.3 2 2.7 m A
NFB
Switch Off Time 400 ns
Switch V I = 60mA (LT1617-1) 85 120 mV
CESAT SW
I = 300mA (LT1617) 250 350 mV
SW
Switch Current Limit LT1617-1 75 100 125 mA
LT1617 300 350 400 mA
SHDN Pin Current V = 1.2V 2 3 m A
SHDN
V = 5V 8 12 m A
SHDN
SHDN Input Voltage High 0.9 V
SHDN Input Voltage Low 0.25 V
Switch Leakage Current Switch Off, V = 5V 0.01 5 m A
SW
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1617 and LT1617-1 are guaranteed to meet specifications
from 0 C to 70 C. Specifications over the 40 C to 85 C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: Bias current flows out of the NFB pin.
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