Document
19-3983; Rev 0; 1/06
KIT ATION EVALU E L B A AVAIL
TFT, LCD, DC-DC Converter with Operational Amplifiers
Features
♦ 1.8V to 5.5V Input Supply Range ♦ 600kHz/1.2MHz Current-Mode Step-Up Regulator Fast Transient Response to Pulsed Load High-Accuracy Output Voltage (1.5%) Built-In 14V, 1.9A, 0.2Ω n-Channel MOSFET High Efficiency (> 85%) Digital Soft-Start ♦ Two High-Performance Operational Amplifiers ±150mA Output Short-Circuit Current 7.5V/µs Slew Rate 12MHz, -3dB Bandwidth Rail-to-Rail Inputs/Outputs ♦ Logic-Controlled, High-Voltage Switch with Adjustable Delay ♦ Built-In Power-Up Sequence ♦ Input Supply Undervoltage Lockout ♦ Timer Delay Fault Latch for All Regulator Outputs ♦ Thermal-Overload Protection
General Description
The MAX8739 includes a high-performance, step-up regulator and two high-current operational amplifiers for active-matrix thin-film transistor (TFT) liquid-crystal displays (LCDs). The input supply voltage range of the MAX8739 is from 1.8V to 5.5V. The device also includes a logic-controlled, high-voltage switch with adjustable delay. The step-up DC-DC converter provides the regulated www.DataSheet4U.com supply voltage for the panel source driver ICs. The converter is a high-frequency (600kHz/1.2MHz) currentmode regulator with an integrated 14V n-channel MOSFET that allows the use of ultra-small inductors and ceramic capacitors. It provides fast transient response to pulsed loads while achieving efficiencies over 85%. The two high-performance operational amplifiers are designed to drive the LCD backplane (VCOM) and/or the gamma-correction-divider string. The devices feature high output current (±150mA), fast slew rate (7.5V/µs), wide bandwidth (12MHz), and rail-to-rail inputs and outputs. The MAX8739 is available in a 20-pin, 5mm × 5mm thin QFN package with a maximum thickness of 0.8mm for ultra-thin LCD panels.
MAX8739
Applications
Notebook Computer Displays LCD Monitor Panels Automotive Displays
Simplified Operating Circuit
VIN +1.8V TO +5.5V LX IN FB MAX8739 FREQ COMP NEG1 OUT1 TO VCOM BACKPLANE NEG2 OUT2 LDO POS1 POS2 AGND PGND SUP
VMAIN
Ordering Information
PART MAX8739ETP+ TEMP RANGE -40°C to +85°C PIN-PACKAGE PKG CODE
20 Thin QFN-EP* T2055-2 (5mm x 5mm)
+ Denotes lead-free package. * EP = Exposed pads.
DEL
Pin Configuration appears at end of data sheet.
FROM TCON CTL
SRC DRN COM
________________________________________________________________ Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
TFT, LCD, DC-DC Converter with Operational Amplifiers
IN, CTL, FREQ, LDO to AGND .................................-0.3V to +6V COMP, FB, DEL to AGND ........................-0.3V to (VLDO + 0.3V) PGND to AGND ..................................................................±0.3V LX to PGND ............................................................-0.3V to +14V SUP to AGND .........................................................-0.3V to +14V POS1, POS2, NEG1, NEG2, OUT1, OUT2 to AGND .....................................-0.3V to (VSUP + 0.3V) SRC to AGND .........................................................-0.3V to +30V COM, DRN to AGND ................................-0.3V to (VSRC + 0.3V) www.DataSheet4U.com COM RMS Output Current................................................±50mA
MAX8739
ABSOLUTE MAXIMUM RATINGS
OUT1, OUT2 Maximum Continuous Output Current ........±75mA LX Switch Maximum Continuous RMS Output Current .........1.6A Continuous Power Dissipation (TA = +70°C) 20-Pin, 5mm × 5mm, Thin QFN (derate 20.8mW/°C above +70°C).............................................................1667mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C
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
(VIN = 2.5V, VSUP = 10V, VSRC = 28V, FREQ = CTL = IN, PGND = AGND = 0, TA = 0°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.)
PARAMETER IN Supply Range IN Quiescent Current IN Undervoltage Lockout Threshold LDO Output Voltage LDO Undervoltage Lockout Threshold LDO Output Current SUP Supply Voltage Range SUP Undervoltage Fault Threshold SUP Supply Current Thermal Shutdown STEP-UP REGULATOR Operating Frequency Maximum Duty Cycle FREQ Input Low Voltage FREQ Input High Voltage FREQ Pulldown Current FB Regulation Voltage .