EVALUATION KIT AVAILABLE MAX17126B Multi-Output Power Supplies with VCOM Amplifier and High-Voltage Gamma Reference for LCD TVs General Description Features The MAX17126B generates all the supply rails for thin- S 8.0V to 16.5V IN Supply Voltage Range film transistor liquid-crystal display (TFT LCD) TV panels S Selectable Frequency (500kHz/750kHz) operating from a regulated 12V input. They include a S Current-Mode Step-Up Regulator step-down and a step-up regulator, a positive and a Fast Load-Transient Response negative charge pump, an operational amplifier, a high- High-Accuracy Output Voltage (1.0%) accuracy high-voltage gamma reference, and a high- Built-In 20V, 3.5A, 100mI MOSFET voltage switch control block. The device can operate High Efficiency from input voltages from 8V to 16.5V and is optimized Adjustable Soft-Start for an LCD TV panel running directly from 12V supplies. Adjustable Current Limit The step-up and step-down switching regulators feature Low Duty-Cycle Operation (13.2V - 13.5V AVDD) IN internal power MOSFETs and high-frequency opera- S Current-Mode Step-Down Regulator tion allowing the use of small inductors and capacitors, Fast Load-Transient Response resulting in a compact solution. The step-up regulator Built-In 20V, 3.2A, 100mI MOSFET provides TFT source driver supply voltage, while the High Efficiency step-down regulator provides the system with logic sup- 3ms Internal Soft-Start ply voltage. Both regulators use fixed-frequency current- S Adjustable Positive Charge-Pump Regulator mode control architectures, providing fast load-transient response and easy compensation. A current-limit func- S Adjustable Negative Charge-Pump Regulator tion for internal switches and output-fault shutdown S Integrated High-Voltage Switch with Adjustable protects the step-up and step-down power supplies Turn-On Delay against fault conditions. The device provides soft-start S High-Speed Operational Amplifier functions to limit inrush current during startup. In addi- 200mA Short-Circuit Current tion, the device integrates a control block that can drive 45V/s Slew Rate an external p-channel MOSFET to sequence power to source drivers. S High-Accuracy Reference for Gamma Buffer 1% Feedback Voltage The positive and negative charge-pump regulators pro- Up to 30mA Load Current vide TFT gate-driver supply voltages. Both output volt- Low-Dropout Voltage 0.5V at 60mA ages can be adjusted with external resistive voltage- dividers. A logic-controlled, high-voltage switch block S External p-Channel Gate Control for AVDD allows the manipulation of the positive gate-driver supply. Sequencing The device includes one high-current operational ampli- S XAO Comparator fier designed to drive the LCD backplane (VCOM). The S Input Undervoltage Lockout and Thermal- amplifier features high output current (Q200mA), fast Overload Protection slew rate (45V/Fs), wide bandwidth (20MHz), and rail-to- S 48-Pin, 7mm x 7mm, TQFN Package rail outputs. Also featured in the device is a high-accuracy, high- Ordering Information voltage adjustable reference for gamma correction. The device is available in a small (7mm x 7mm), ultra-thin PART TEMP RANGE PIN-PACKAGE (0.8mm), 48-pin TQFN package and operates over the MAX17126BETM+ 48 TQFN-EP* -40NC to +85NC -40NC to +85NC temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Applications LCD TV Panels Visit www.maximintegrated.com/products/patents for product patent marking information. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-6050 Rev 0 9/11MAX17126B Multi-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) ..................................3.2A XAO, VDET, VREF FB, OUT to GND .............-0.3V, (V + 0.3) RMS PGND CURRENT (total for both pins) .........................3.2A L GD, GD I to GND ..................................................-0.3V to +24V RMS IN2 Current (total for both pins) ..................................3.2A LX1 to PGND .........................................................-0.3V to +24V RMS LX2 Current (total for both pins) ..................................3.2A 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) TQFN (derated 38.5mW/NC above +70NC) ............3076.9mW SUPN to GND .............................................-0.3V to (IN2 + 0.3V) Junction Temperature .....................................................+160NC SUPP to GND ..........................................-0.3V to (GD I + 0.3V) Storage Temperature Range ............................ -65NC to +165NC BST to VL ...............................................................-0.3V to +30V Lead Temperature (soldering, 10s) ................................+300NC VGH to GND ..........................................................-0.3V to +40V Soldering Temperature (reflow) ......................................+260NC VGHM, DRN to GND ..................................... -0.3V, VGH + 0.3V 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 10 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 Maxim Integrated