LT1615/LT1615-1
Micropower Step-Up
DC/DC Converters
in ThinSOT
DESCRIPTIO
FEATURES
n
Low Quiescent Current: The LT 1615/LT1615-1 are micropower step-up DC/DC
20m A in Active Mode converters in a 5-lead low profile (1mm) ThinSOT pack-
<1m A in Shutdown Mode age. The LT1615 is designed for higher power systems
n
Operates with V as Low as 1V with a 350mA current limit and an input voltage range of
IN
n
Low V Switch: 250mV at 300mA 1.2V to 15V, whereas the LT1615-1 is intended for lower
CESAT
n
Uses Small Surface Mount Components power and single-cell applications with a 100mA current
n
High Output Voltage: Up to 34V limit and an extended input voltage range of 1V to 15V.
TM
n
Low Profile (1mm) ThinSOT Package Otherwise, the two devices are functionally equivalent.
Both devices feature a quiescent current of only 20m A at no
U
load, which further reduces to 0.5m A in shutdown. A
APPLICATIO S
current limited, fixed off-time control scheme conserves
operating current, resulting in high efficiency over a broad
n
LCD Bias
range of load current. The 36V switch allows high voltage
n
Handheld Computers
outputs up to 34V to be easily generated in a simple boost
n
Battery Backup
topology without the use of costly transformers. The
n
Digital Cameras
LT1615s low off-time of 400ns permits the use of 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.
ThinSOT is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
1-Cell Li-Ion to 20V Converter for LCD Bias
Efficiency
85
L1
D1
10H
80
V 20V
IN
V = 4.2V
2.5V TO 4.2V 12mA IN
75
R1
V SW
IN
V = 3.3V
IN
2M
V = 2.5V
70 IN
C2
LT1615
1F
65
SHDN FB
GND
C1
R2
4.7F 60
130k
55
C1: TAIYO YUDEN LMK316BJ475
1615/-1 TA01
C2: TAIYO YUDEN TMK316BJ105
D1: MOTOROLA MBR0530
50
L1: MURATA LQH3C100K24
0.1 0.3 1 3 10 30
LOAD CURRENT (mA)
1615/-1 TA01a
sn16151 16151fas
1
EFFICIENCY (%)
U
ULT1615/LT1615-1
UUW
ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
V , SHDN Voltage ................................................... 15V NUMBER
IN
SW Voltage .............................................................. 36V
LT1615ES5
TOP VIEW
FB Voltage .................................................................V
IN
LT1615ES5-1
SW 1 5 V
IN
Current into FB Pin ................................................. 1mA
LT1615IS5
GND 2
Junction Temperature........................................... 125 C
LT1615IS5-1
FB 3 4 SHDN
Operating Temperature Range (Note 2) .. 40 C to 85 C
S5 PACKAGE
Storage Temperature Range ................. 65 C to 150 C
S5 PART MARKING
5-LEAD PLASTIC SOT-23
Lead Temperature (Soldering, 10 sec).................. 300 C
T = 125 C, q = 256 C/W
JMAX JA
LTIZ
LTKH
LTXZ
LTBHT
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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 LT1615-1 1.0 V
LT1615 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 30 80 nA
FB
Switch Off Time V > 1V 400 ns
FB
V < 0.6V 1.5 m s
FB
Switch V I = 70mA (LT1615-1) 85 120 mV
CESAT SW
I = 300mA (LT1615) 250 350 mV
SW
Switch Current Limit LT1615-1 75 100 125 mA
LT1615 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 characterization and correlation with statistical process controls. The
of a device may be impaired. LT1615I/LT1615I-1 is guaranteed to meet performance specifications over
the 40 C to 85 C operating temperature range.
Note 2: The LT1615E and LT1615E-1 are guaranteed to meet performance
specifications from 0 C to 70 C. Specifications over the Note 3: Bias current flows into the FB pin.
40 C to 85 C operating temperature range are assured by design,
sn16151 16151fas
2
U WWW