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LT1316
Micropower
DC/DC Converter
with Programmable
Peak Current Limit
■
Precise Control of Peak Switch Current
■
Quiescent Current:
33µA in Active Mode
3µA in Shutdown Mode
■
Low-Battery Detector Active in Shutdown
■
Low Switch V
CESAT
: 300mV at 500mA
■
8-Lead MSOP and SO Packages
■
Operates with V
IN
as Low as 1.5V
■
Logic Level Shutdown Pin
FEATURES
DESCRIPTION
U
The LT
®
1316 is a micropower step-up DC/DC converter
that operates from an input voltage as low as 1.5V. A
programmable input current limiting function allows pre-
cise control of peak switch current. Peak switch current
can be set to any value between 30mA and 500mA by
adjusting one resistor. This is particularly useful for
DC/DC converters operating from high source impedance
inputs such as lithium coin cells or telephone lines.
The fixed off-time, variable on-time regulation scheme
results in quiescent current of only 33µA in active mode.
Quiescent current decreases to 3µA in shutdown with the
low-battery detector still active.
The LT1316 is available in 8-lead MSOP and SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
U
APPLICATIONS
U
■
Battery Backup
■
LCD Bias
■
Low Power –48V to 5V/3.3V Converters
2-Cell to 5V Step-Up Converter
V
IN
SW
R
SET
GND
FBSHDN
65
8
1
43
2
7
LBOLBI
LT1316
C2
47µF
NC NC
R5
10k
1%
C1
47µF
2 CELLS
L1
47µH
D1
5V
50mA
D1: MOTOROLA MBR0520L
L1: SUMIDA CD43-470
1316 TA01
+
+
R1
1M
1%
R2
324k
1%
LOAD CURRENT (mA)
0.1
60
EFFICIENCY (%)
80
90
1 10 100
1316 TA02
70
3.3V
IN
2.5V
IN
1.8V
IN
Efficiency vs Load Current
