Power Management Inductorless (Charge Pump) DC/DC Converters Unregulated Doubling/Inverting Charge Pumps

Obsolete

For New Designs

LTC1550 - Low Noise, Switched Capacitor-Regulated Voltage Inverters

LTC1429 - Clock-Synchronized Switched Capacitor Regulated Voltage Inverter

Features

  • Obsolete - Datasheet For Information Purposes Only.  Contact Linear Technology for Potential Replacement
  • Regulated Negative Voltage from a Single Positive Supply
  • External Clock for Synchronization in Noise Sensitive Systems
  • REG Output Indicates Output is in Regulation
  • Low Output Ripple: 5mV Typ
  • Can Provide Regulated 5V from a 3V Supply
  • Supply Current: 600µA Typ
  • Shutdown Mode Drops Supply Current to 0.2µA
  • Up to 12mA Output Current
  • Adjustable or Fixed Output Voltages
  • Requries Only Three or Four External Caps
  • Output Regulation: 5%
  • Available in SO-8 Packages

Typical Application

LTC1429 Typical Application
LTC1429 Typical Application

Description

Obsolete - Datasheet For Information Purposes Only.  Contact Linear Technology for Potential Replacement

The LTC®1429 is a switched-capacitor voltage inverter designed to provide a regulated negative voltage from a single positive supply and permits clock synchronization in noise sensitive systems. The LTC1429CS 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 LTC1429CS to be configured for output voltages of -3.5V, -4V,-4.5V or -5V. The LTC1429CS8 is optimized for applications which require a fixed -4V output from a 5V supply and requires only a single external 0.1µF flying capacitor. The LTC1429CS 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 LTC1429 guarantees output regulation of 5%. The LTC1429 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. The LTC1429 requires an external clock applied to the SYNC/SD for normal operation and consumes a typical quiescent current of 600µA. Holding the SYNC/SD either high or low brings the device into shutdown and the supply current drops to 0.2µA. For applications which don’t have a clock signal available, the LTC1261 provides the same functionality with an internal oscillator. For applications which require output ripple below 1mV, see the LTC1550/LTC1551. The LTC1429CS is available in a 14-pin SO package and the LTC1429CS8 is available in an 8-pin SO package.

Packaging

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

LTC1429 Package Drawing
LTC1429 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

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

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Models for the following parts are available in LTspice:
LTC1429
LTC1429CS8-4

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