MAX17122 19-4951 Rev 1 11/09 Step-Up, Step-Down Regulator, Gate-On Charge Pump, and Boost-Buck Regulator for TV TFT LCD Display General Description Features S 8V to 16.5V Operating Range The MAX17122 multiple-output power-supply IC gener- ates all the supply rails for thin-film transistor (TFT) liquid- S 750kHz Switching Frequency crystal display (LCD) TV panels. It can operate from 8V S 22V Internal-Switch High-Performance Step-Up to 16.5V input voltages and is optimized for LCD TV Regulator panel applications running directly from 12V regulated Fast Load-Transient Response supplies. It includes a 22V internal-switch step-down Current-Mode PWM Operation regulator for digital logic, a 22V internal switch step- 100mI, 3.9A nMOS Switch up regulator to power the TFT source drivers, and a Capacitor-Adjustable Soft-Start High-Voltage Stress Function temperature-compensated 36V internal-switch boost- Drives External pMOS Shutdown Switch buck regulator that produces a negative output that can vary according to the temperature sensed by an exter- S 22V Internal-Switch Step-Down Regulator Preset 1% Accurate 3.3V Output Voltage or nal NTC thermistor. All three of these regulators feature Adjustable Output (Dual Mode) high-efficiency and fixed-frequency operation. High- Current-Mode PWM Operation frequency operation allows the use of small inductors 200mI, 2.5A nMOS Switch and capacitors, resulting in a compact solution. Capacitor-Adjustable Power-Good Output The MAX17122 includes a positive charge-pump linear S 36V Internal-Switch Boost-Buck Regulator regulator controller that uses an external pnp bipolar Temperature-Compensated Output junction transistor (BJT) to typically form a regulated Programmable Fixed Levels with Temperature- charge-pump doubler to supply the LCD positive gate- Controlled Transition driver supply voltage. A negative gate-driver supply is Current-Mode PWM Operation derived linearly between the boost-buck regulators out- 200mI, 1.8A pMOS Switch put and ground, using an external npn BJT connected to S Positive Charge-Pump Linear Regulator Controller ground and a small bypass capacitor. Adjustable 1% Accurate Output Voltage Uses External pnp Transistor Other features include an external-capacitor-timed, Regulates Switching-Node-Driven Charge- open-drain, power-good output that monitors the step- Pump Doubler down regulators feedback and a simple untimed output Power-Good Output that monitors the positive charge-pump linear regulators S Negative Linear Regulator Controller feedback. A high-voltage stress function is available for Adjustable 1.5% Accurate Output Voltage the step-up regulator output. The GATE output directly Uses External npn Transistor drives an external p-channel MOSFET to provide True S Soft-Start for All Outputs ShutdownK of the step-up output. S Adjustable Power-Up Sequence The MAX17122 is available in a 6mm x 6mm, 40-pin thin S Timed-Output Fault Protection with Restart for All QFN lead-free package and operates over the -40NC to Outputs +85NC temperature range. S Latched Thermal-Shutdown Protection Applications S 40-Pin, 6mm x 6mm Thin QFN Package LCD TV Panels Ordering Information PART TEMP RANGE PIN-PACKAGE MAX17122ETL+ -40NC to +85NC 40 TQFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. True Shutdown and Dual Mode are trademarks of Maxim Pin Configuration appears at end of data sheet. Integrated Products, Inc. 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 AVAILABLEStep-Up, Step-Down Regulator, Gate-On Charge Pump, and Boost-Buck Regulator for TV TFT LCD Display ABSOLUTE MAXIMUM RATINGS IN, IN2, IN3, EN1, EN2, LX1, GATE, BST2 to LX2 .............................................................-0.3V to +6V DRVP, RHVS to AGND ......................................-0.3V to +22V RMS LX1, GND1, IN2, IN3, LX3 Current (each pin) ............1.6A GATE to IN ...........................................................-6.5V to +0.3V RMS LX2 (total for both pins) ...............................................2.4A GND1 to AGND .................................................................Q0.3V RMS VL, DRVN, DRVP Current ..........................................50mA DLY1, DLY2, DEL, VL, RESET, GPGD, Continuous Power Dissipation (T = +70NC) A HVS to AGND ......................................................-0.3V to +6V 40-Pin Thin QFN FBP, FBN, FB1, FB2, FB3, COMP1, COMP3, OUTB (derate 35.7mW/NC above +70NC) .........................2857.1mW SET, NTC, SS to AGND ......................... -0.3V to (V + 0.3V) Operating Temperature Range .......................... -40NC to +85NC VL DRVN to VL ...........................................................-36V to +0.3V Junction Temperature .....................................................+160NC LX2 to GND1 ............................................ -0.3V to (V + 0.3V) Storage Temperature Range ............................ -65NC to +165NC IN2 Lead Temperature (soldering, 10s) ................................+300NC LX3 to IN3 ..............................................................-36V to +0.3V BST2 to VL .............................................................-0.3V to +22V Soldering Temperature (reflow) ......................................+260NC 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 = V = 12V, T = 0C to +85C. Typical values are at T = +25NC, unless otherwise noted.) IN IN2 IN3 A A PARAMETER CONDITIONS MIN TYP MAX UNITS GENERAL IN, IN2, IN3 8 16.5 V Input-Voltage Range Only LX2 and LX3 switching (V = V = 1.5V, V = FB1 FBP FB2 10 15 1.1V, V = 1.8V, V = 1.5V) V = V = 5V FB3 FBN EN1 EN2 IN + IN2 + IN3 mA Quiescent Current LX2 and LX3 not switching (V = V = V = 1.5V, FB1 FB2 FBP 2 4 V = 1.5V, V = 0) V = V = 5V FBN FB3 EN1 EN2 IN + IN2 + IN3 EN1 = EN2 = AGND (shutdown) 0.55 1 mA Shutdown Current SMPS Operating Frequency 638 750 862 kHz Step-down and boost-buck 180 Phase Difference Between Degrees Regulators Step-down and step-up 180 IN Undervoltage-Lockout V rising, 2.5% hysteresis 6 7 8 V IN Threshold VL REGULATOR I = 10mA, V = V = V = 1.1V, V = 0.75V, VL FB1 FB2 FBP FBN VL Output Voltage 4.9 5.0 5.1 V V = 1.8V (all regulators switching) FB3 VL Undervoltage-Lockout 3.6 4.0 4.4 V VL rising, 2.5% hysteresis Threshold STEP-DOWN REGULATOR 3.267 3.300 3.333 T = +25NC A OUTB Voltage in Fixed Mode FB2 = AGND, no load (Note 1) V 0NC < T < +85NC 3.25 3.35 A T = +25NC 1.2375 1.250 1.2625 A FB2 Voltage in Adjustable Mode V = 3.3V, no load (Note 1) V OUTB 0NC < T < +85NC 1.23 1.27 A FB2 Adjustable-Mode Dual-mode comparator 0.10 0.15 0.20 V Threshold Voltage 2 MAX17122