MAX17126/MAX17126A 19-4681 Rev 1 3/10 Multi-Output Power Supplies with VCOM Amplifier and High-Voltage Gamma Reference for LCD TVs General Description Features The MAX17126/MAX17126A generate all the supply rails S 8.0V to 16.5V IN Supply-Voltage Range for thin-film transistor liquid-crystal display (TFT LCD) S Selectable Frequency (500kHz/750kHz) TV panels operating from a regulated 12V input. They S Current-Mode Step-Up Regulator include a step-down and a step-up regulator, a positive Fast Load-Transient Response and a negative charge pump, an operational amplifier, High-Accuracy Output Voltage (1.0%) a high-accuracy high-voltage gamma reference, and Built-In 20V, 4.2A, 100mI MOSFET a high-voltage switch control block. The MAX17126/ High Efficiency MAX17126A can operate from input voltages from 8V Adjustable Soft-Start to 16.5V and is optimized for an LCD TV panel running Adjustable Current Limit directly from 12V supplies. Low Duty-Cycle Operation (13.2V - 13.5V AVDD) IN The step-up and step-down switching regulators feature S Current-Mode Step-Down Regulator internal power MOSFETs and high-frequency opera- Fast Load-Transient Response tion allowing the use of small inductors and capacitors, Built-In 20V, 3.2A, 100mI MOSFET resulting in a compact solution. The step-up regulator High Efficiency provides TFT source driver supply voltage, while the 3ms Internal Soft-Start step-down regulator provides the system with logic sup- S Adjustable Positive Charge-Pump Regulator ply voltage. Both regulators use fixed-frequency current- mode control architectures, providing fast load-transient S Adjustable Negative Charge-Pump Regulator response and easy compensation. A current-limit func- S Integrated High-Voltage Switch with Adjustable tion for internal switches and output-fault shutdown pro- Turn-On Delay tects the step-up and step-down power supplies against S High-Speed Operational Amplifier fault conditions. The MAX17126/MAX17126A provide Q200mA Short-Circuit Current soft-start functions to limit inrush current during startup. 45V/s Slew Rate In addition, the MAX17126/MAX17126A integrate a con- trol block that can drive an external p-channel MOSFET S High-Accuracy Reference for Gamma Buffer to sequence power to source drivers. Q1% Feedback Voltage Up to 30mA Load Current The positive and negative charge-pump regulators pro- Low-Dropout Voltage 0.5V at 60mA vide TFT gate-driver supply voltages. Both output volt- ages can be adjusted with external resistive voltage- S External p-Channel Gate Control for AVDD dividers. A logic-controlled, high-voltage switch block Sequencing allows the manipulation of the positive gate-driver supply. S PGOOD Comparator The MAX17126/MAX17126A include one high-current S Input Undervoltage Lockout and Thermal- operational amplifier designed to drive the LCD back- Overload Protection plane (VCOM). The amplifier features high output cur- S 48-Pin, 7mm x 7mm, Thin QFN Package rent (Q200mA), fast slew rate (45V/Fs), wide bandwidth (20MHz), and rail-to-rail outputs. Ordering Information Also featured in the MAX17126/MAX17126A is a high- accuracy, high-voltage adjustable reference for gamma PART TEMP RANGE PIN-PACKAGE correction. MAX17126ETM+ -40NC to +85NC 48 Thin QFN-EP* The MAX17126/MAX17126A are available in a small (7mm MAX17126AETM+ -40NC to +85NC 48 Thin QFN-EP* x 7mm), ultra-thin (0.8mm), 48-pin thin QFN package and +Denotes a lead(Pb)-free/RoHS-compliant package. operate over the -40NC to +85NC temperature range. *EP = Exposed pad. Applications LCD TV Panels Pin Configuration appears 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. EVALUATION KIT AVAILABLEMulti-Output Power Supplies with VCOM Amplifier and High-Voltage Gamma Reference for LCD TVs ABSOLUTE MAXIMUM RATINGS INVL, IN2, VOP, EN, FSEL to GND .......................-0.3V to +24V VREF I to GND ......................................................-0.3V to +24V PGND, OGND, CPGND to GND ..........................-0.3V to +0.3V VREF O to GND .......................................-0.3V, (V + 0.3)V REF I DLY1, GVOFF, THR, VL to GND ..........................-0.3V to +7.5V REF Short Circuit to GND ..........................................Continuous REF, FBP, FBN, FB1, FB2, COMP, SS, CLIM, RMS LX1 Current (total for both pins) .................................3.2 A PGOOD, VDET, VREF FB, OUT to GND ........-0.3V, (V + 0.3) RMS PGND CURRENT (total for both pins) ........................3.2 A L GD, GD I to GND ..................................................-0.3V to +24V RMS IN2 Current (total for both pins) .................................3.2 A LX1 to PGND .........................................................-0.3V to +24V RMS LX2 Current (total for both pins) .................................3.2 A OPP, OPN, OPO to OGND ......................... -0.3V to VOP + 0.3V RMS DRVN, DRVP Current ..................................................0.8A DRVP to CPGND ...................................... -0.3V to SUPP + 0.3V RMS VL Current ..................................................................50mA DRVN to CPGND ...................................... -0.3V to SUPN + 0.3V Continuous Power Dissipation (T +70NC) A = LX2 to PGND ................................................-0.7 to (IN2 + 0.3V) 48-Pin TQFN SUPN to GND .............................................-0.3V to (IN2 + 0.3V) (derated 38.5mW/NC above +70NC) .......................3076.9mW SUPP to GND .......................................... -0.3V to (GD I + 0.3V) Junction Temperature .....................................................+160NC BST to VL ...............................................................-0.3V to +30V Storage Temperature Range ............................ -65NC to +165NC VGH to GND ..........................................................-0.3V to +40V Lead Temperature (soldering, 10s) ................................+300NC VGHM, DRN to GND ..................................... -0.3V, VGH + 0.3V Soldering Temperature (reflow) ......................................+260NC VGHM to DRN .......................................................-0.3V to +40V 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 (Circuit of Figure 1, V = V = 12V, V = V = 15V, T = 0C to +85C. Typical values are at T = +25NC, unless oth- INVL IN2 VOP VREF I A A erwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS GENERAL INVL, IN2 Input-Voltage Range 8 16.5 V Only LX2 switching (V = V = 1.5V, V = 0V) FB1 FBP FBN INVL + IN2 Quiescent Current 8.5 20 mA EN = VL, FSEL = high LX2 not switching (V = V = V = 1.5V, FB1 FB2 FBP INVL + IN2 Standby Current 24 5 mA V = 0V), EN = VL, FSEL = high FBN FSEL = INVL or high impedance 630 750 870 SMPS Operating Frequency kHz FSEL = GND 420 500 580 INVL Undervoltage-Lockout INVL rising, 150mV typical hysteresis 6.0 7.0 8.0 V Threshold VL REGULATOR I = 25mA, V = V = V = 1.1V, V = 0.4V VL FB1 FB2 FBP FBN VL Output Voltage 4.85 5 5.15 V (all regulators switching) VL Undervoltage-Lockout VL rising, 50mV typical hysteresis 3.5 3.9 4.3 V Threshold REFERENCE REF Output Voltage No external load 1.2375 1.250 1.2625 V REF Load Regulation 0V < I < 50FA 5 mV LOAD REF Sink Current In regulation 10 FA REF Undervoltage-Lockout Rising edge, 250mV typical hysteresis 1.0 1.2 V Threshold 2 MAX17126/MAX17126A