LTC1261 - Switched Capacitor Regulated Voltage Inverter

Features

  • Regulated Negative Voltage from a Single Positive Supply
  • Can Provide Regulated -5V from a 3V Supply
  • REG Pin Indicates Output is in Regulation
  • Low Output Ripple: 5mV Typ
  • Supply Current: 600µA Typ
  • Shutdown Mode Drops Supply Current to 5µA
  • Up to 15mA Output Current
  • Adjustable or Fixed Output Voltages
  • Requires Only Three or Four External Capacitors
  • Available in SO-8 Packages

Typical Application

LTC1261 Typical Application
LTC1261 Typical Application

Description

The LTC1261 is a switched-capacitor voltage inverter designed to provide a regulated negative voltage from a single positive supply. The LTC1261CS operates from a single 3V to 8V supply and provides an adjustable output voltage from –1.25V to –8V. An on-chip resistor string allows the LTC1261CS to be configured for output voltages of –3.5V, –4V, –4.5V or –5V with no external components. The LTC1261CS8 is optimized for applications which use a 5V or higher supply or which require low output voltages. It requires a single external 0.1µF capacitor and provides adjustable and fixed output voltage options in 8-pin SO packages. The LTC1261CS requires one or two external 0.1µF capacitors, depending on input voltage. Both versions require additional external input and output bypass capacitors. An optional compensation capacitor at ADJ/COMP can be used to reduce the output voltage ripple. Each version of the LTC1261 will supply up to 12mA output current with guaranteed output regulation of 5%. The LTC1261 includes an open-drain REG output which pulls low when the output is within 5% of the set value. Output ripple is typically as low as 5mV. Quiescent current is typically 600µA when operating and 5µA in shutdown. The LTC1261 is available in a 14-pin narrow body SO package and an 8-pin SO 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
LTC1261CS#PBF SO-14 S C 05-08-1610 (S14) Yes
LTC1261CS#TRPBF SO-14 S C 05-08-1610 (S14) Yes
LTC1261CS8-4.5#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1261CS8-4.5#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1261CS8-4#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1261CS8-4#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1261CS8#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1261CS8#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LTC1261IS8#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LTC1261IS8#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes


LTC1261 Package Drawing
LTC1261 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
LTC1261CS#PBF SO-14 C $3.00 $2.50 Yes
LTC1261CS#TRPBF SO-14 C $2.56 Yes
LTC1261CS8-4.5#PBF SO-8 C $2.10 $1.75 Yes
LTC1261CS8-4.5#TRPBF SO-8 C $1.81 Yes
LTC1261CS8-4#PBF SO-8 C $2.10 $1.75 Yes
LTC1261CS8-4#TRPBF SO-8 C $1.81 Yes
LTC1261CS8#PBF SO-8 C $2.10 $1.75 Yes
LTC1261CS8#TRPBF SO-8 C $1.81 Yes
LTC1261IS8#PBF SO-8 I $2.50 $2.10 Yes
LTC1261IS8#TRPBF SO-8 I $2.16 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.

Click here to view our complete list of demo boards

Applications

  • GaAs FET Bias Generators
  • Negative Supply Generators
  • Battery-Powered Systems
  • Single Supply Applications

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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

Models for the following parts are available in LTspice:
LTC1261
LTC1261CS8
LTC1261CS8-4
LTC1261CS8-4.5
LTC1261LCS8
LTC1261LCS8-4
LTC1261LCS8-4.5

Technical Support