MAX754ESE+ Maxim Integrated Products, MAX754ESE+ Datasheet
MAX754ESE+
Specifications of MAX754ESE+
Related parts for MAX754ESE+
MAX754ESE+ Summary of contents
Page 1
... Notebook Computers Palmtop Computers Pen-Based Data Systems Personal Digital Assistants Portable Data-Collection Terminals ________________________________________________________________ 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. CCFL Backlight and LCD Contrast Controllers ____________________________Features ♦ ...
Page 2
CCFL Backlight and LCD Contrast Controllers ABSOLUTE MAXIMUM RATINGS V to GND .................................................................-0.3V, +7V DD PGND to GND.....................................................................±0.3V BATT to GND.............................................................-0.3V, +36V LX to GND............................................................................±50V CS to GND.....................................................-0.6V, (V Inputs/Outputs to GND (LADJ, CADJ, LON, CON, REF, CFB, CC, CDRV, ...
Page 3
ELECTRICAL CHARACTERISTICS (continued 5V, BATT = 15V, CON = LON = 5V GND = PGND = 0V unless otherwise noted.) A MIN MAX PARAMETER Feedback Voltage (CFB) Feedback-Amplifier ...
Page 4
CCFL Backlight and LCD Contrast Controllers ______________________________________________________________Pin Description PIN NAME Power-Supply Input DD 2 LADJ Digital Input for LCD Backplane Bias Adjustment. See Table 1. 3 LON Digital Input to Control LCD Bias Section. See Table 1. ...
Page 5
CS BATT D1B D1A C1 MAX754CSE 4 CON 5 CADJ 3 LON 2 LADJ D2B D2A 11 CDRV REF C4 13 LDRV 12 PGND 16 LFB 6 GND CFB ...
Page 6
CCFL Backlight and LCD Contrast Controllers 1250 1221 1191 811 782 753 402 372 343 DAC CODE MID SCALE ZERO SCALE Figure 2. CCFT DAC Transfer Function MAX754 FULL-SCALE = 1.250V HALF-SCALE = ...
Page 7
V (t) SEC I (t) LAMP Figure 4. Simple Model of the CCFL The minimum operating input voltage is determined by the transformer turns ratio (n), the lamp operating volt- age (V ), and the ballast capactor (C10). Using a ...
Page 8
CCFL Backlight and LCD Contrast Controllers +5V INPUT C1 0.22µ LADJ LON V ON/OFF CONTROL PRESET 6-BIT COUNTER CLK MAX754 6-BIT DAC PGND GND 12 6 Figure 6. MAX754 Positive LCD-Bias Generator Table 1. CCFL Circuit Component Descriptions ...
Page 9
Table 1. CCFL Circuit Component Descriptions (continued) ITEM The ballast capacitor linearizes the CCFL impedance and guarantees no DC current through the lamp. 15pF will work with just about any lamp. Depending on the lamp, you can try higher values, ...
Page 10
CCFL Backlight and LCD Contrast Controllers Table 2. CCFL Circuit Design Example (Note 1) PARAMETER CCFL Specifications Strike Voltage ( Discharging Tube Current ( Discharging Tube Voltage ( LCD Contrast Voltage Specifications Bias Voltage ...
Page 11
Table 3. Spreadsheet Design Equations PARAMETER CCFL Specifications Strike Voltage ( Discharging Tube Current ( Discharging Tube Voltage ( LCD Contrast Voltage Specifications Bias Voltage Output Current Royer Specifications T1 Turns Ratio (Sec/Pri) T1 ...
Page 12
CCFL Backlight and LCD Contrast Controllers Table 4. Bill of Materials RESISTOR VALUE (Ω) TOLERANCE (%) R1 100,000 R2 100,000 R3 1,000,000 R4 40,200 R5 100,000 R6 13,300 R7 100,000 R8 549 R10 680 R16 100,000 R17 100,000 R18 100,000 ...
Page 13
Positive LCD Bias: MAX754 The voltage-regulation loop is comprised of resistors R3 and R4, the pulse-skip comparator, the internal DAC, the on-time and off-time logic, and the external power components. The comparator compares a fraction of the output voltage to ...
Page 14
CCFL Backlight and LCD Contrast Controllers Table 5. Logic-Signal Truth Table CCF CONTROL LON LADJ LCD BIAS CONTROL LON LADJ 0→1 Hold = maintain last ...
Page 15
INPUT C1 0.22µ LADJ LON V DD ON-TIME LOGIC ON/OFF CONTROL PRESET 6-BIT COUNTER CLK MAX753 6-BIT DAC PGND GND 12 6 Figure 8. MAX753 Negative LCD-Bias Generator 1240 1230 1220 937 928 918 645 ...
Page 16
... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 1995 Maxim Integrated Products ___________________Chip Topography ...