General Description The MAX8728 generates all the supply rails for thin-film transistor (TFT) liquid-crystal display (LCD) panels in TVs and monitors. It includes step-down and step-up regula- tors, positive and negative charge pumps, and a dual- mode, logic-controlled high-voltage switch control block. The MAX8728 can operate from input voltages from 7V to 13.2V and is optimized for LCD TV panel and LCD moni- tor applications running directly from 12V supplies.The step-up and step-down regulators feature internal power MOSFETs and high-frequency operation allow- ing the use of small inductors and capacitors, resulting in a compact solution. Both switching regulators use fixed-frequency, current-mode control architectures, providing fast load-transient response and easy com- pensation. The positive and negative charge-pump reg- ulators provide TFT gate-driver supply voltages. Both output voltages can be adjusted with external resistive voltage-dividers. The MAX8728 is available in a small (5mm x 5mm), low- profile (0.8mm), 32-pin TQFN package and operates over the -40C to +85C temperature range.Applications LCD MonitorsLCD TVsFeatures Optimized for 10.8V to 13.2V Input Supply 7V to 13.2V Input Supply Range Selectable Frequency (500kHz/1MHz/1.5MHz) Current-Mode Step-Down Regulator 14V Internal n-Channel MOSFET 1.5% Accurate Output Current-Mode Step-Up Regulator 19V Internal n-Channel MOSFET 1% Accurate Output True Shutdown (Output Goes to Zero) 180 Out-of-Phase Switching Adjustable Positive/Negative Charge Pumps Soft-Start and Timer Delay Fault Latch for All Outputs Logic-Controlled, High-Voltage Switches Power-Up and Power-Down Sequences Thermal-Overload ProtectionMAX8728Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs_ Maxim Integrated Products1Ordering InformationMAX8728AVDDVGONGATEINLVINOUT1VGOFFVLVLLX1ON/OFFOUT1FBI FSELGND1GNDFBPSRCREFVCCGONDRNMODETHRCOMPSHDN LCD ENABLEENFROM TCONCTLDELFB2LX2 GND2FBN DRVN SUPPDRVPVLBST INVINSimplified Operating Circuit19-3910; Rev 0; 1/06For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.PARTTEMP RANGEPIN- PACKAGEPACKAGE CODEMAX8728ETJ+-40C to +85C32 TQFN-EP* 5mm x 5mmT3255-4Pin ConfigurationMAX8728TQFNTOP VIEW29302827121113OUT1CTLINLX1BST14GND1FB2DRNGONFBNSRCFSEL12EN4567232422201918MODEDELFBPREFGNDSHDNDRVNTHR3213110COMPVCC329FB1VLGATE2615GNDPLX22516DRVPINLSUPP817GND2+Denotes lead-free package. *EP = Exposed pad.True Shutdown is a trademark of Maxim Integrated Products, Inc.MAX8728Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs2_ABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICS(Circuit of Figure 1, VIN= VINL= VSUPP= 12V, VOUT1= +3.3V, VSRC= 28V, GND1 = GND2 = GNDP = GND = 0, IREF= 0, TA= 0C to +85C. Typical values are at TA= +25C, unless otherwise noted.)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.IN, INL, SUPP to GND.-0.3V to +14V SUPP to IN.0.3V DRVP to GNDP.-0.3V to VSUPP + 0.3V CTL, EN, SHDN, OUT1, VL, VCCto GND.-0.3V to +6V COMP, FB1, FB2, FBN, FBP, FSEL, DEL, THR, MODE, REF to GND.-0.3V to VCC + 0.3V GND1, GND2, GNDP to GND.0.3V BST to GND1.-0.3V to +20V LX1 to BST.-6V to +0.3V LX2 to GND2 .-0.3V to +19V DRVN, LX1, GATE to GND1 .-0.3V to VIN + 0.3V GON, SRC to GND.-0.3V to +40V SRC to GON.-0.3V to +40V SRC to SUPP.-0.3V to +30V SRC to SUPP (momentary).-14V to +30V GON to SUPP.-14V to +30VSRC to DRN.-0.3V to +40V DRN to GND.-0.3V to +40V GON to DRN.-0.3V to +30V VLShort Circuit to GND.Momentary REF Short Circuit to GND.