LTC1522 Datasheet, PDF (1/8 Pages) Linear Technology – Micropower, Regulated 5V Charge Pump DC/DC Converter

LTC1522
Micropower, Regulated
5V Charge Pump
DC/DC Converter
FEATURES
s _{Ultralow Power: Typical Operating ICC = 6µA}
s _{Short-Circuit/Thermal Protected}
s _{Regulated 5V ±4% Output Voltage}
s _{2.7V to 5V Input Range}
s _{No Inductors}
s _{Very Low ICC in Shutdown: < 1µA}
s _{Output Current: 10mA (VIN ≥ 2.7V)}
20mA (V_IN ≥ 3V)
s _{Shutdown Disconnects Load from VIN}
s _{Internal Oscillator: 700kHz}
s _{Compact Application Circuit (< 0.1 in}²₎
s _{8-Pin MSOP and SO Packages}
U
APPLICATIONS
s _{SIM Interface Supplies for GSM Cellular Telephones}
s _{Li-Ion Battery Backup Supplies}
s _{Local 3V to 5V Conversion}
s _{Smart Card Readers}
s _{PCMCIA Local 5V Supplies}
DESCRIPTION
The LTC^®1522 is a micropower charge pump DC/DC
converter that produces a regulated 5V output from a 2.7V
to 5V input supply. Extremely low supply current (6µA
typical with no load, < 1µA in shutdown) and low external
parts count (one 0.22µF flying capacitor and two 10µF
capacitors at V_IN and V_OUT) make the LTC1522 ideally
suited for small, light load battery-powered applications.
Typical efficiency (V_IN = 3V) exceeds 75% with load
currents between 50µA and 20mA. Modulating the SHDN
pin keeps the typical efficiency above 75% with load
currents all the way down to 10µA.
The LTC1522 has thermal shutdown and can survive a
continuous short from V_OUT to GND. In shutdown the
load is disconnected from V_IN. The part is available in
8-pin MSOP and SO packages. The LTC1522 is pin
compatible with the LTC1516 in applications where
V_IN ≥ 2.7V and I_OUT ≤ 20mA.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
Regulated 5V Output from a 2.7V to 5V Input
V_IN
2.7V TO 5V ₊
1 _NC
NC ⁸
10µF
2 _VIN
SHDN ⁷ ON/OFF
LTC1522
3 _VOUT
GND ⁶
+
10µF _{4 C+}
C^{– 5}
0.22µF
V_OUT = 5V ±4%
I_OUT = 0mA TO 10mA, V_IN ≥ 2.7V
I_OUT = 0mA TO 20mA, V_IN ≥ 3V
1522 TA01
Efficiency vs Output Current
90
V_IN = 3V
80
LOW I_Q MODE
(SEE FIGURE 2)
70
SHDN = 0V
60
50
0.01
0.1
1
10
OUTPUT CURRENT (mA)
100
1522 TA02
1