MAX1748/MAX8726 19-3430 Rev 0 10/04 Triple-Output TFT-LCD DC-DC Converters General Description Features The MAX1748/MAX8726 triple-output DC-DC converters Three Integrated DC-DC Converters in a low-profile TSSOP package provide the regulated 1MHz Current-Mode PWM Boost Regulator voltages required by active-matrix, thin-film transistor Up to +13V Main High-Power Output (TFT) liquid-crystal displays (LCDs). One high-power 1% Accuracy DC-DC converter and two low-power charge pumps High Efficiency (93%) convert the +3.3V to +5V input supply voltage into three independent output voltages. Dual Charge-Pump Outputs Up to +40V Positive Charge-Pump Output The primary 1MHz DC-DC converter generates a boost- Down to -40V Negative Charge-Pump Output ed output voltage (V ) up to 13V using ultra-small MAIN inductors and ceramic capacitors. The low-power Internal Supply Sequencing BiCMOS control circuitry and the low on-resistance Internal Power MOSFETs (0.35) of the integrated power MOSFET allows effi- +2.7V to +5.5V Input Supply ciency up to 93%. 0.1A Shutdown Current The dual charge pumps independently regulate one 0.6mA Quiescent Current positive output (V ) and one negative output (V ). POS NEG These low-power outputs use external diode and Internal Soft-Start capacitor stages (as many stages as required) to regu- Power-Ready Output late output voltages up to +40V and down to -40V. A Ultra-Small External Components proprietary regulation algorithm minimizes output rip- ple, as well as capacitor sizes for both charge pumps. Thin TSSOP Package (1.1mm max) For both the MAX1748 and MAX8726, the supply sequence is V first, V next, and finally V . MAIN NEG POS The MAX1748 soft-starts each supply as soon as the Ordering Information previous supply finishes. The MAX8726 adds a delay PART TEMP RANGE PIN-PACKAGE between the startups of V and V and also MAIN NEG between V and V . MAX1748EUE -40C to +85C 16 TSSOP NEG POS The MAX1748/MAX8726 are available in the ultra-thin MAX8726EUE -40C to +85C 16 TSSOP TSSOP package (1.1mm max height). Applications Pin Configuration TFT Active-Matrix LCD Displays TOP VIEW Passive-Matrix LCD Displays RDY 1 16 TGND PDAs FB 2 15 LX Digital Still Cameras INTG 3 14 PGND Camcorders IN 4 MAX1748 13 SUPP MAX8726 GND 5 12 DRVP REF 6 11 SUPN FBP 7 10 DRVN FBN 8 9 SHDN TSSOP A SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES. Typical Operating Circuit appears at end of data sheet. Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. EVALUATION KIT AVAILABLETriple-Output TFT-LCD DC-DC Converters 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 MAX1748EUE/MAX8726EUE..........................-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 = 470pF, T = 0C to +85C, unless IN SUPP SUPN REF INTG A 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 0.6 1 mA IN FB FBP FBN SUPP Quiescent Current I V = 1.5V 0.4 0.8 mA SUPP FBP SUPN Quiescent Current I V = -0.1V 0.4 0.8 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 T = 0C to +85C 1.235 1.248 1.261 V FB A FB Input Bias Current I V = 1.25V, INTG = GND -50 +50 nA FB FB Operating Frequency f 0.85 1 1.15 MHz OSC Oscillator Maximum Duty Cycle 78 85 90 % Load Regulation I = 0 to 200mA, V = 10V 0.2 % MAIN MAIN Line Regulation 0.1 % / V Integrator Gm 320 mho LX Switch On-Resistance R I = 100mA 0.35 0.7 LX(ON) LX LX Leakage Current I V = 13V 0.01 20 A LX LX Phase I = soft-start (1.0ms) 0.275 0.380 0.500 Phase II = soft-start (1.0ms) 0.75 LX Current Limit I A LX(MAX) Phase III = soft-start (1.0ms) 1.12 Phase IV = fully on (after 3.0ms) 1.1 1.5 2.0 Maximum RMS LX Current 1A 3072 / Soft-Start Period t Power-up to the end of phase III s SS f OSC FB Fault Trip Level 1.07 1.1 1.14 V POSITIVE CHARGE PUMP V Input Supply Range V 2.7 13.0 V SUPP SUPP 2 MAX1748/MAX8726