MAX753/MAX754 19-0197 Rev 1 1/95 CCFL Backlight and LCD Contrast Controllers General Description Features The MAX753/MAX754 drive cold-cathode fluorescent Drives Backplane and Backlight lamps (CCFLs) and provide the LCD backplane bias 4V to 30V Battery Voltage Range (contrast) power for color or monochrome LCD panels. These ICs are designed specifically for backlit note- Low 500A Supply Current book-computer applications. Digital or Potentiometer Control of CCFL Both the backplane bias and the CCFL supply can be Brightness and LCD Bias Voltage shut down independently. When both sections are shut down, supply current drops to 25A. The LCD contrast Negative LCD Contrast (MAX753) and CCFL brightness can be adjusted by clocking sep- Positive LCD Contrast (MAX754) arate digital inputs or using external potentiometers. LCD contrast and backlight brightness settings are pre- Independent Shutdown of Backlight and served in their respective counters while in shutdown. Backplane Sections On power-up, the LCD contrast counter and CCFL 25A Shutdown Supply Current 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 Ordering Information maximum power efficiency. The CCFL driver uses a Royer-type resonant architec- PART TEMP. RANGE PIN-PACKAGE ture. It can provide from 100mW to 6W of power to one MAX753CPE 0C to +70C 16 Plastic DIP or two tubes. The MAX753 provides a negative LCD MAX753CSE 0C to +70C 16 Narrow SO bias voltage the MAX754 provides a positive LCD bias voltage. MAX753C/D 0C to +70C Dice* MAX753EPE -40C to +85C 16 Plastic DIP Applications MAX753ESE -40C to +85C 16 Narrow SO Notebook Computers MAX754CPE 0C to +70C 16 Plastic DIP Palmtop Computers MAX754CSE 0C to +70C 16 Narrow SO MAX754C/D 0C to +70C Dice* Pen-Based Data Systems MAX754EPE -40C to +85C 16 Plastic DIP Personal Digital Assistants MAX754ESE -40C to +85C 16 Narrow SO Portable Data-Collection Terminals * Contact factory for dice specifications. Pin Configuration TOP VIEW V LFB DD 1 16 LADJ BATT 2 15 LON LX 3 14 CON LDRV 4 MAX753 13 MAX754 CADJ 5 PGND 12 GND 6 11 CDRV REF CS 7 10 CFB 8 9 CC DIP/SO Block Diagram located at end of data sheet. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.CCFL Backlight and LCD Contrast Controllers ABSOLUTE MAXIMUM RATINGS V to GND.................................................................-0.3V, +7V Operating Temperature Ranges DD PGND to GND.....................................................................0.3V MAX75 C ........................................................0C to +70C BATT to GND.............................................................-0.3V, +36V MAX75 E ......................................................-40C to +85C LX to GND............................................................................50V Junction Temperature......................................................+150C CS to GND.....................................................-0.6V, (V + 0.3V) Storage Temperature Range .............................-65C to +160C DD Inputs/Outputs to GND (LADJ, CADJ, LON, Lead Temperature (soldering, 10sec) .............................+300C CON, REF, CFB, CC, CDRV, LDRV, LFB) .....-0.3V, (V + 0.3V) DD Continuous Power Dissipation (T = +70C) A Plastic DIP (derate 10.53mW/C above +70C) ...........842mW Narrow SO (derate 8.70mW/C above +70C) .............696mW Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = 5V, BATT = 15V, CON = LON = 5V, LX = GND = PGND = 0V, I = 0mA, all digital input levels are 0V or 5V, DD REF T = T to T , unless otherwise noted.) A MIN MAX PARAMETER CONDITIONS MIN TYP MAX UNITS SUPPLY AND REFERENCE BATT Input Range 430 V V Supply Range 4.5 5.5 V DD REF Output Voltage No external load 1.21 1.25 1.29 V REF Line Regulation 4V < V < 6V 0.1 %/V DD REF Load Regulation 0A < I < 100A 515 mV L LON = CON = CS = LFB = CFB = V Quiescent Current 0.5 2 mA DD LADJ = CADJ = 5V LON = CON = CS = LFB = CFB = LADJ V Shutdown Current 25 40 A DD = CADJ = LX = BATT = 0V (Note 1) DIGITAL INPUTS AND DRIVER OUTPUTS Input Low Voltage LON, CON, CADJ, LADJ V = 4.5V 0.8 V DD Input High Voltage LON, CON, CADJ, LADJ V = 5.5V 2.4 V DD Input Leakage Current LON, CON, CADJ, LADJ V = 0V or 5V 1 A IN Driver Sink/Source Current LDRV = CDRV = 2V 0.5 A Output high 10 LDRV, CDRV Driver On-Resistance V = 4.5V DD Output low 7 CCFT CONTROLLER Zero-Crossing-Comparator Threshold Voltage (CS) -10 20 mV Overcurrent-Comparator Threshold Voltage (CS) 1.2 1.3 V CS Input Bias Current V = 0V -5 A CS Minimum, CFB = 5V 32 47 VCO Frequency kHz Maximum, CFB = 0V 85 115 DAC Resolution Guaranteed monotonic 5 Bits 2 MAX753/MAX754