LTC3240-3.3_15 Datasheet, PDF (1/12 Pages) Linear Technology – 3.3V/2.5V Step-Up/ Step-Down Charge Pump DC/DC Converter

LTC3240-3.3/LTC3240-2.5
3.3V/2.5V Step-Up/
Step-Down Charge Pump
DC/DC Converter
FEATURES
■ _{Step-Up/Step-Down Charge Pumps Generate Fixed}
3.3V or 2.5V Outputs
■ _{VIN Range: 1.8V to 5.5V}
■ _{Output Current up to 150mA}
■ _{Automatic Mode Switching}
■ _{Constant Frequency (1.2MHz) Operation in}
Step-Up Mode
■ _{Low Dropout Regulator Operation in}
Step-Down Mode
■ _{Low No-Load Quiescent Current: IQ = 65µA}
■ _{Built-In Soft-Start Reduces Inrush Current}
■ _{Shutdown Disconnects Load from Input}
■ _{Shutdown Current < 1µA}
■ _{Short-Circuit/Thermal Protection}
■ _{Available in a 6-Lead (2mm × 2mm) DFN Package}
U
APPLICATIO S
■ _{2 AA to 2.5V}
■ _{2-3 AA/Li-Ion to 3.3V}
■ _{Low Power Supplies for Cameras, I/O Supplies,}
Audio, PC Cards, Misc. Logic, etc., in a Wide Variety
of Handheld Products
DESCRIPTIO
The LTC^®3240-3.3/LTC3240-2.5 are step-up/step-down
charge pump DC/DC converters that produce a fixed
regulated output voltage of 3.3V or 2.5V over a wide input
voltage range (1.8V to 5.5V).
With input voltages greater than the regulated output
voltage the LTC3240 operates as a low dropout regulator.
Once the input voltage drops within 100mV of the regulated
output voltage the part automatically switches to step-up
mode. In step-up mode the LTC3240 operates as a constant
frequency (1.2MHz) doubling charge pump.
The LTC3240-3.3/LTC3240-2.5 feature low no load operat-
ing current (65µA typical) and ultralow operating current
in shutdown (<1µA). Built-in soft-start circuitry prevents
excessive inrush current during start-up. Thermal shut-
down and current-limit circuitry allow the parts to survive
a continuous short-circuit from V_OUT to GND.
The LTC3240-3.3/LTC3240-2.5 require only three tiny
external ceramic capacitors for an ultrasmall application
footprint. The LTC3240-3.3/LTC3240-2.5 are available in a
6-pin (2mm × 2mm) DFN package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6411531.
TYPICAL APPLICATIO
Li-Ion to 3.3V at Up to 150mA
1µF
2.7V TO 4.5V
Li-Ion OR
1µF
3-CELL NiMH
C^–
V_IN
C⁺
V_OUT
LTC3240-3.3
GND
3.3V
I_OUT = 150mA
4.7µF
OFF ON
SHDN
3240 TA01a
Output Voltage vs Input Voltage (Full Range)
3.50
I_OUT = 30mA
3.45
3.40
3.35
3.30
3.25
3.20
3.15
3.10
1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7
INPUT VOLTAGE (V)
3240 TA01b
3240fb
1