LTC3240

PRODUCTION

3.3V/2.5V Step-Up/Step-Down Charge Pump DC/DC Converter

Part Models: 4
1ku List Price: Starting From $2.15

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Overview

Step-Up/Step-Down Charge Pumps Generate Fixed 3.3V or 2.5V Outputs
V_IN 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: I_Q = 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

The LTC3240-3.3/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 operating current (65µA typical) and ultralow operating current in shutdown (<1µA). Built-in soft-start circuitry prevents excessive inrush current during start-up. Thermal shutdown 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.

Applications

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

Part Models: 4
1ku List Price: Starting From $2.15

Documentation

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LTC3240EDC-2.5#TRMPBF	6-Lead DFN (2mm x 2mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3240EDC-2.5#TRPBF	6-Lead DFN (2mm x 2mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3240EDC-3.3#TRMPBF	6-Lead DFN (2mm x 2mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3240EDC-3.3#TRPBF	6-Lead DFN (2mm x 2mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Tools & Simulations

LTspice 2

Models for the following parts are available in LTspice:

LTC3240-2.5
LTC3240-3.3

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

Evaluation Kits

LTC3240EDC-2.5 Demo Board | Regulated Buck-Boost Charge Pump, 1.8V ≤ VIN ≤ 5.5V, VOUT = 2.5V @ Up to 150mA

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Product Details

Demonstration circuit 903 is a step-up/step-down charge pump dc-dc converter. It comes with two assembly versions, DC903A-A and DC903A-B featuring the 150mA output current LTC3240-3.3 (3.3V output) and LTC3240-2.5 (2.5V output) respectively, each in a tiny 2mm x 2mm DFN package. The DC903A-A and DC903A-B operate with an input voltage from 1.8V to 5.5V.

When using the DC903A-A, the output current can reach up to 150mA when the input voltage is above 2.5V. The maximum output current of the DC903A-B is 60mA with a 1.8V input voltage. The DC903A optimizes the output efficiency by operating in the LDO step-down mode during the time the input is higher than the output voltage. When the input voltage drops low enough, The LTC3240 automatically switches to charge-pump doubling mode to extend system run-time. Built-in soft-start limits inrush current at turn-on, and short-circuit current limit/thermal protection help the part survive a continuous short-circuit.

Additionally, the DC903A features Automatic Burst Mode operation at light load to achieve low supply current (65µA, no load).