MAX1790/MAX8715 19-1563 Rev 3 9/05 Low-Noise Step-Up DC-DC Converters General Description Features The MAX1790/MAX8715 boost converters incorporate 90% Efficiency high-performance (at 1.2MHz), current-mode, fixed-fre- Adjustable Output from V to 12V IN quency, pulse-width modulation (PWM) circuitry with a built-in 0.21/0.15 n-channel MOSFET to provide a high- 1.6A, 0.21, 14V Power MOSFET (MAX1790) ly efficient regulator with fast response. 2.4A, 0.15, 14V Power MOSFET (MAX8715) High switching frequency (640kHz or 1.2MHz selectable) allows easy filtering and faster loop performance. An +2.6V to +5.5V Input Range external compensation pin provides the user flexibility in Pin-Selectable 640kHz or 1.2MHz Switching determining loop dynamics, allowing the use of small, low Frequency equivalent-series-resistance (ESR) ceramic output capaci- tors. The device can produce an output voltage as high as 0.1A Shutdown Current 12V from an input as low as 2.6V. Programmable Soft-Start Soft-start is programmed with an external capacitor, which Small 8-Pin MAX Package sets the input-current ramp rate. In shutdown mode, cur- rent consumption is reduced to 0.1A. The MAX1790/ MAX8715 are available in a space-saving 8-pin MAX package. The ultra-small package and high switching fre- Ordering Information quency allow the total solution to be less than 1.1mm high. MAX is a registered trademark of Maxim Integrated Products, PART TEMP RANGE PIN-PACKAGE Inc. MAX1790EUA -40C to +85C 8 MAX Applications MAX1790EUA+ -40C to +85C 8 MAX LCD Displays MAX8715EUA -40C to +85C 8 MAX PCMCIA Cards MAX8715EUA+ -40C to +85C 8 MAX Portable Applications + Denotes lead-free package. Hand-Held Devices Typical Operating Circuit Pin Configuration V IN 2.6V TO 5V TOP VIEW COMP 1 8 SS IN V OUT FB 2 7 FREQ ON/OFF SHDN LX MAX1790 MAX8715 SHDN 3 6 IN MAX1790 MAX8715 GND 4 5 LX FREQ GND MAX SS FB COMP 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. EVALUATION KIT AVAILABLELow-Noise Step-Up DC-DC Converters ABSOLUTE MAXIMUM RATINGS LX to GND ..............................................................-0.3V to +14V Operating Temperature Range IN, SHDN, FREQ, FB to GND ................................-0.3V to +6.2V MAX1790EUA/MAX8715EUA ........................-40C to +85C SS, COMP to GND.......................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C IN RMS LX Pin Current ..............................................................1.2A Storage Temperature Range .............................-65C to +150C Continuous Power Dissipation (T = +70C) Lead Temperature (soldering, 10s) .................................+300C A 8-Pin MAX (derate 4.1mW/C above +70C) .............330mW 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 = SHDN = 3V, FREQ = GND, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) IN A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Supply Range V 2.6 5.5 V IN V rising, typical hysteresis is 40mV, IN V Undervoltage Lockout UVLO 2.25 2.38 2.52 V IN LX remains off below this level V = 1.3V, not switching 0.18 0.35 FB MAX1790 V = 1.0V, switching 2 5 FB Quiescent Current I mA IN V = 1.3V, not switching 0.21 0.35 FB MAX8715 V = 1.0V, switching 2.5 5.0 FB Shutdown Supply Current I SHDN = GND 0.1 10 A IN ERROR AMPLIFIER Feedback Voltage V Level to produce V = 1.24V 1.222 1.24 1.258 V FB COMP MAX1790 0 40 FB Input Bias Current I V = 1.24V nA FB FB MAX8715 125 190 Feedback-Voltage Line Level to produce V = 1.24V, COMP 0.05 0.15 %/V Regulation 2.6V < V < 5.5V IN MAX1790 70 140 240 Transconductance g I = 5A S m MAX8715 70 160 240 Voltage Gain A 700 V/V V OSCILLATOR FREQ = GND 540 640 740 Frequency f kHz OSC FREQ = IN 1000 1220 1500 FREQ = GND 79 85 92 Maximum Duty Cycle DC % FREQ = IN 84 N-CHANNEL SWITCH V = 1V, MAX1790 1.2 1.6 2.3 FB Current Limit I duty cycle = A LIM MAX8715 1.8 2.4 3.4 65% (Note 1) MAX1790 0.21 0.5 On-Resistance R ON MAX8715 0.15 0.35 MAX1790 0.01 20 Leakage Current I V = 12V A LXOFF LX MAX8715 5 30 2 MAX1790/MAX8715