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Digitally Adjustable LCD Bias Supply

Capable for generating >-100V

Product Details

Key Features

Parametric specs for Inverting Switching Regulators
VIN (V) (min) 2
VIN (V) (max) 6
VOUT1 (V) (min) -2
VOUT1 (V) (max) -100
IOUT1 (A) (max) 0.1
Switch Type External
Output Adjust. Method Resistor
# DC-DC Outputs 1
Switching Frequency (kHz) 500
Package/Pins PDIP/8
SOIC (N)/8
Budgetary
Price (See Notes)
3.33
View Less

Simplified Block Diagram

Technical Docs

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Sampling:
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Parameters

Parametric specs for Inverting Switching Regulators
VIN (V) (min) 2
VIN (V) (max) 6
VOUT1 (V) (min) -2
VOUT1 (V) (max) -100
IOUT1 (A) (max) 0.1
Switch Type External
Output Adjust. Method Resistor
# DC-DC Outputs 1
Switching Frequency (kHz) 500
Package/Pins PDIP/8
SOIC (N)/8
Budgetary
Price (See Notes)
3.33

Key Features

  • +2.0V to +6.0V Input Voltage Range
  • Flexible Control of Output Voltage:
    • Digital Control
    • Potentiometer Adjustment
    • PWM Control
  • Output Voltage Range Set by One Resistor
  • Low, 60µA Max Quiescent Current
  • 15µA Max Shutdown Mode
  • Small Size - 8-Pin SO and Plastic DIP Packages

Applications/Uses

  • Communication Systems
  • Laptop Computers
  • Notebook Computers
  • Palmtop Computers
  • PDAs and Other Handheld Devices
  • Portable Data-Collection Terminals

Description

The MAX749 generates negative LCD-bias contrast voltages from 2V to 6V inputs. Full-scale output voltage can be scaled to -100V or greater, and is digitally adjustable in 64 equal steps by an internal digital-to-analog converter (DAC). Only seven small surface-mount components are required to build a complete supply. The output voltage can also be adjusted using a PWM signal or a potentiometer.

A unique current-limited control scheme reduces supply current and maximizes efficiency, while a high switching frequency (up to 500kHz) minimizes the size of external components. Quiescent current is only 60µA max and is reduced to under 15µA in shutdown mode. While shut down, the MAX749 retains the voltage set point, simplifying software control. The MAX749 drives either an external P-channel MOSFET or a PNP transistor.

Simplified Block Diagram

MAX749: Typical Operating Circuit MAX749: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.