LTC1516
Micropower, Regulated
5V Charge Pump
DC/DC Converter
FEATURES
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DESCRIPTION
The LTC
®
1516 is a micropower charge pump DC/DC
converter that produces a regulated 5V output from a 2V
to 5V supply. Extremely low supply current (12µA typical
with no load, < 1µA in shutdown) and low external parts
count (two 0.22µF flying capacitors and two 10µF capaci-
tors at V
IN
and V
OUT
) make the LTC1516 ideally suited for
small, light load battery-powered applications. Typical
efficiency (V
IN
= 3V) exceeds 70% with load currents
between 50µA and 50mA. Modulating the SHDN pin keeps
the typical efficiency above 70% with load currents all the
way down to 10µA.
The LTC1516 operates as either a doubler or a tripler
depending on V
IN
and output load conditions to improve
overall efficiency. The part has thermal shutdown and can
survive a continuous short from V
OUT
to GND. In shut-
down the load is disconnected from V
IN
.
The LTC1516 is available in an 8-pin SO package in both
commercial and industrial temperature grades.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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Ultralow Power: Typical Operating I
CC
= 12µA
Short Circuit/Thermal Protection
Regulated 5V
±4%
Output
2V to 5V Input Range
No Inductors
I
CC
in Shutdown: < 1µA
Output Current: 20mA (V
IN
> 2V)
50mA (V
IN
> 3V)
Shutdown Disconnects Load from V
IN
Internal Oscillator: 600kHz
Compact Application Circuit (0.1 in
2
)
8-Pin SO Package
APPLICATIONS
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2-Cell to 5V Conversion
Li-Ion Battery Backup Supplies
Local 3V to 5V Conversion
5V Flash Memory Programmer
Smart Card Readers
TYPICAL APPLICATION
0.22µF
Efficiency vs Output Current
90
V
IN
= 3V
1
2
C1
+
V
IN
V
OUT
C2
+
0.22µF
C1
–
SHDN
LTC1516
GND
C2
–
8
80
+
10µF
3
10µF 4
EFFICIENCY (%)
V
IN
= 2V TO 5V
7
6
5
ON/OFF
70
+
SHDN = 0V
60
V
OUT
= 5V
±4%
I
OUT
= 0mA TO 20mA, V
IN
≥
2V
I
OUT
= 0mA TO 50mA, V
IN
≥
3V
50
0.01
1516 • F01
Figure 1. Regulated 5V Output from a 2V to 5V Input
U
U
U
LOW I
Q
MODE
(SEE FIGURE 3)
0.1
1
10
OUTPUT CURRENT (mA)
100
1516 • TA01
1
LINER [ LINEAR TECHNOLOGY ]
