Maxim > Products > Power and Battery Management > MAX749

MAX749

Digitally Adjustable LCD Bias Supply

Capable for generating >-100V

Overview

Technical Documents

Ordering Info

Status

Active: In Production.

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.

Data Sheet

Download	Rev 1	(PDF, 120kB)
E-Mail

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

Key Specifications:

Inverting Switching Regulators

Part Number

V_IN
(V)

V_OUT
(V)

Max. I_OUT
(A)

Output Adjust. Method

DC-DC Outputs

Oper. Freq.
(kHz)

Package/Pins

Smallest Available Pckg.
(mm²)

Budgetary Price

min

max

min

max

≥

≤

max w/pins

See Notes

MAX749

-2

-100

0.1

Resistor

500

PDIP(N)/8

SOIC(N)/8

30.9

$2.79 @1k

See All Inverting Switching Regulators (25)

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Diagram

Typical Operating Circuit

Notes and Comments

Drives P-channel MOSFET or PNP

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Information Index

Overview		Technical Documents		Ordering Info		Related Products
Description Key Features Applications/Uses Key Specifications Diagram Notes and Comments		Data Sheet Application Notes Evaluation Kits Product Guides Reliability Reports Software/Models		Price and Availability Samples Buy Online Package Information Lead-Free Information		Similar Products by Function Similar Products by Application Evaluation Kits Products with Similar Part Numbers Products Used With This

Document Ref.: 19-0143 Rev 1; 1995-02-01
This page last modified: 2007-07-17