19-0197; Rev 1; 1/95
CCFL Backlight and
LCD Contrast Controllers
The MAX753/MAX754 drive cold-cathode fluorescent
lamps (CCFLs) and provide the LCD backplane bias
(contrast) power for color or monochrome LCD panels.
These ICs are designed specifically for backlit notebook-computer applications.
Both the backplane bias and the CCFL supply can be
shut down independently. When both sections are shut
down, supply current drops to 25µA. The LCD contrast
and CCFL brightness can be adjusted by clocking separate digital inputs or using external potentiometers.
LCD contrast and backlight brightness settings are preserved in their respective counters while in shutdown.
On power-up, the LCD contrast counter and CCFL
brightness counter are set to one-half scale.
The ICs are powered from a regulated 5V supply. The
magnetics are connected directly to the battery, for
maximum power efficiency.
The CCFL driver uses a Royer-type resonant architecture. It can provide from 100mW to 6W of power to one
or two tubes. The MAX753 provides a negative LCD
bias voltage; the MAX754 provides a positive LCD bias
voltage.
________________________Applications
Notebook Computers
Palmtop Computers
Pen-Based Data Systems
Personal Digital Assistants
Portable Data-Collection Terminals
____________________________Features
♦ Drives Backplane and Backlight
♦ 4V to 30V Battery Voltage Range
♦ Low 500µA Supply Current
♦ Digital or Potentiometer Control of CCFL
Brightness and LCD Bias Voltage
♦ Negative LCD Contrast (MAX753)
♦ Positive LCD Contrast (MAX754)
♦ Independent Shutdown of Backlight and
Backplane Sections
♦ 25µA Shutdown Supply Current
______________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX753CPE
0°C to +70°C
16 Plastic DIP
MAX753CSE
MAX753C/D
MAX753EPE
MAX753ESE
MAX754CPE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
16 Narrow SO
Dice*
16 Plastic DIP
16 Narrow SO
16 Plastic DIP
MAX754CSE
MAX754C/D
MAX754EPE
MAX754ESE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
16 Narrow SO
Dice*
16 Plastic DIP
16 Narrow SO
* Contact factory for dice specifications.
__________________Pin Configuration
TOP VIEW
VDD 1
16 LFB
LADJ 2
15 BATT
LON 3
CON 4
CADJ 5
14 LX
MAX753
MAX754
13 LDRV
12 PGND
GND 6
11 CDRV
REF 7
10 CS
CFB 8
9
CC
DIP/SO
Block Diagram located at end of data sheet.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX753/MAX754
_______________General Description
