MAX1779 19-1795 Rev 1 9/05 Low-Power Triple-Output TFT LCD DC-DC Converter General Description Features The MAX1779 triple-output DC-DC converter provides Three Integrated DC-DC Converters highly efficient regulated voltages required by small 250kHz Current-Mode PWM Boost Regulator active matrix, thin-film transistor (TFT) liquid-crystal dis- Up to +13V Main High-Power Output plays (LCDs). One high-power DC-DC converter and 1% Accuracy two low-power charge pumps convert the +2.7V to High Efficiency (91%) +5.5V input supply voltage into three independent out- put voltages. Dual Charge-Pump Outputs Up to +40V Positive Charge-Pump Output The primary high-power DC-DC converter generates a Down to -40V Negative Charge-Pump Output boosted output voltage (V ) up to 13V that is regu- MAIN lated within 1%. The low-power BiCMOS control cir- Internal Supply Sequencing cuitry and the low on-resistance (1) of the integrated Internal Power MOSFETs power MOSFET allows efficiency up to 91%. The +2.7V to +5.5V Input Supply 250kHz current-mode pulse-width modulation (PWM) 0.1A Shutdown Current architecture provides fast transient response and allows the use of ultra-small inductors and ceramic 0.5mA Quiescent Current capacitors. Internal Soft-Start The dual charge pumps independently regulate one Power-Ready Output positive output (V ) and one negative output (V ). POS NEG Ultra-Small External Components These low-power outputs use external diode and capacitor stages (as many stages as required) to regu- Thin TSSOP Package (1.1mm max) late output voltages up to +40V and down to -40V. A proprietary regulation algorithm minimizes output rip- ple, as well as capacitor sizes for both charge pumps. Ordering Information The MAX1779 is available in the ultra-thin TSSOP pack- age (1.1mm max height). PART TEMP RANGE PIN-PACKAGE MAX1779EUE -40C to +85C 16 TSSOP MAX1779EUE+ -40C to +85C 16 TSSOP + Denotes lead-free package. Pin Configuration Applications TOP VIEW TFT Active-Matrix LCD Displays RDY 1 16 TGND Passive-Matrix LCD Displays FB 2 15 LX PDAs INTG 3 14 PGND Digital-Still Cameras IN 4 MAX1748 13 SUPP Camcorders MAX8726 GND 5 12 DRVP REF 6 11 SUPN FBP 7 10 DRVN FBN 8 9 SHDN TSSOP Typical Operating Circuit appears at end of data sheet. A SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Low-Power Triple-Output TFT LCD DC-DC Converter ABSOLUTE MAXIMUM RATINGS Continuous Power Dissipation (T = +70C) IN, SHDN, TGND to GND.........................................-0.3V to +6V A 16-Pin TSSOP (derate 9.4mW/C above +70C) ..........755mW DRVN to GND.........................................-0.3V to (V + 0.3V) SUPN DRVP to GND..........................................-0.3V to (V + 0.3V) Operating Temperature Range SUPP MAX1779EUE ..................................................-40C to +85C PGND to GND.....................................................................0.3V RDY to GND ...........................................................-0.3V to +14V Junction Temperature......................................................+150C Storage Temperature Range .............................-65C to +150C LX, SUPP, SUPN to PGND .....................................-0.3V to +14V Lead Temperature (soldering, 10s) .................................+300C INTG, REF, FB, FBN, FBP to GND...............-0.3V to (V + 0.3V) IN 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 (V = +3.0V, SHDN = IN, V = V = +10V, TGND = PGND = GND, C = 0.22F, C = 2200pF, T = 0C to +85C, IN SUPP SUPN REF INTG A unless otherwise noted. Typical values are at T = +25C.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Supply Range V 2.7 5.5 V IN Input Undervoltage Threshold V V rising, 40mV hysteresis (typ) 2.2 2.4 2.6 V UVLO IN IN Quiescent Supply Current I V = V = +1.5V, V = -0.2V 0.5 1 mA IN FB FBP FBN SUPP Quiescent Current I V = +1.5V 0.25 0.55 mA SUPP FBP SUPN Quiescent Current I V = -0.1V 0.25 0.55 mA SUPN FBN IN Shutdown Current V = 0, V = +5V 0.1 10 A SHDN IN SUPP Shutdown Current V = 0, V = +13V 0.1 10 A SHDN SUPP SUPN Shutdown Current V = 0, V = +13V 0.1 10 A SHDN SUPN MAIN BOOST CONVERTER Output Voltage Range V V 13 V MAIN IN FB Regulation Voltage V 1.235 1.248 1.261 V FB FB Input Bias Current I V = +1.25V, INTG = GND -50 50 nA FB FB Operating Frequency f 212 250 288 kHz OSC Oscillator Maximum Duty Cycle 79 85 92 % Load Regulation I = 0 to 50mA, V = +5V 0.1 % MAIN MAIN Line Regulation 0.1 % / V Integrator Gm 320 s LX Switch On-Resistance R I = 100mA 1.0 2.0 LX(ON) LX LX Leakage Current I V = +13V 0.01 20 A LX LX LX Current Limit I 350 450 650 mA LIM Maximum RMS LX Current 250 mA FB Fault Trip Level Falling edge 1.07 1.1 1.14 V POSITIVE CHARGE PUMP V Input Supply Range V 2.7 13 V SUPP SUPP 2 MAX1779