LTC3240 - 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

Typical Application

LTC3240 Typical Application
LTC3240 Typical Application

Description

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 VOUT 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.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LTC3240EDC-2.5#PBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC3240EDC-2.5#TRMPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC3240EDC-2.5#TRPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC3240EDC-3.3#PBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC3240EDC-3.3#TRMPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes
LTC3240EDC-3.3#TRPBF 2x2 DFN-6 DC6 E 05-08-1703 Yes


LTC3240 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC3240EDC-2.5#PBF 2x2 DFN-6 E $2.36 Yes
LTC3240EDC-2.5#TRMPBF 2x2 DFN-6 E $2.36 $1.65 Yes
LTC3240EDC-2.5#TRPBF 2x2 DFN-6 E $2.36 $1.60 Yes
LTC3240EDC-3.3#PBF 2x2 DFN-6 E $2.36 Yes
LTC3240EDC-3.3#TRMPBF 2x2 DFN-6 E $2.36 $1.65 Yes
LTC3240EDC-3.3#TRPBF 2x2 DFN-6 E $2.36 $1.60 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC903A-A LTC3240EDC-3.3 Demo Board | Regulated Buck-Boost Charge Pump, 1.8V ≤ VIN ≤ 5.5V, Vout = 3.3V @ Up to 150mA $75.00
DC903A-B LTC3240EDC-2.5 Demo Board | Regulated Buck-Boost Charge Pump, 1.8V ≤ VIN ≤ 5.5V, Vout = 2.5V @ Up to 150mA $75.00
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Click here to view our complete list of demo boards

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

Product Notifications

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LTC3240-2.5
LTC3240-3.3

Technical Support