MAX1730 19-1618 Rev 0 4/00 50mA Regulated Step-Down Charge Pump for 1.8V or 1.9V Logic General Description Features The MAX1730 regulated step-down charge pump gen- > 85% Peak Efficiency erates up to 50mA at fixed output voltages of 1.8V or 50mA Guaranteed Output Current 1.9V from an input voltage in the 2.7V to 5.5V range. Dual-Mode 1.8V or 1.9V Output Specifically designed to provide high-efficiency logic supplies in applications that demand a compact 3% Output Voltage Accuracy design, the MAX1730 employs fractional conversion Up to 2MHz Operating Frequency techniques to provide efficiency exceeding that of a lin- ear regulator. Small 0.22F Capacitors The MAX1730 operates at up to 2MHz, permitting the No Inductor Required use of small 0.22F flying capacitors while maintaining 2.7V to 5.5V Input Voltage Range low 75A quiescent supply current. Proprietary soft- start circuitry prevents excessive current from being Output Disconnects from Input in Shutdown Mode drawn from the supply during startup, making the Small 10-Pin MAX Package (1.09mm max height) MAX1730 compatible with higher impedance sources such as alkaline and lithium-ion cells. The MAX1730 is available in a space-saving 10-pin MAX package that is only 1.09mm high and occupies one-half the area of an 8-pin SO. Applications Ordering Information Low-Voltage Logic Supplies PART TEMP. RANGE PIN-PACKAGE MAX1730EUB -40C to +85C 10 MAX Wireless Handsets PDAs PC Cards Hand-Held Instruments Pin Configuration Typical Operating Circuit INPUT TOP VIEW 2.7V TO 5.5V 1 F FB 1 10 IN OUTPUT SHDN 2 9 OUT 1.8V OR 1.9V, UP TO 50mA IN MAX1730 SHDN OUT C1P 3 8 C2P 4.7 F C1N 4 7 C2N MAX1730 GND 5 6 PGND C1P C2P MAX 0.22 F 0.22 F C1N C2N FB PGND GND 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 1-800-835-8769.50mA Regulated Step-Down Charge Pump for 1.8V or 1.9V Logic ABSOLUTE MAXIMUM RATINGS IN, OUT, SHDN, FB to GND .....................................-0.3V to +6V Junction Temperature......................................................+150C Operating Temperature Range ...........................-40C to +85C C1P, C1N, C2P, C2N to GND......................-0.3V to (V + 0.3V) IN GND to PGND.....................................................................0.3V Storage Temperature Range .............................-65C to +150C Lead Temperature Range (soldering, 10s)......................+300C Output Short-Circuit Duration ........................................Indefinite Continuous Power Dissipation (T = +70C) A 10-Pin MAX (derate 5.6mW/C above +70C) ...........444mW 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 = +3.6V, FB = GND, SHDN = IN, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) IN A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Voltage Range V 2.7 5.5 V IN Input Undervoltage Lockout Falling edge (100mV hysteresis) 2.3 2.6 V FB = GND 1.746 1.80 1.854 V = 2.7V to 5.5V, IN Output Voltage V V OUT I = 0 to 50mA OUT FB = IN 1.843 1.90 1.957 OUT forced to 1.8V, V = 1.8V to 5.5V, IN Output Leakage Current 15 A SHDN = GND No-Load Supply Current SHDN = IN 75 150 A Shutdown Supply Current V = 4.2V, SHDN = GND, V = 1.8V or GND 15 A IN OUT Output Short-Circuit Current V = GND 45 125 mA OUT Oscillator Frequency 1.5 2.0 2.5 MHz Thermal Shutdown Threshold 150 C Thermal Shutdown Threshold C 15 Hysteresis From 1:1 to 2:3 3.1 3.2 3.35 V Transition Voltage IN FB = GND V (V Rising) IN From 2:3 to 1:2 4.00 4.12 4.30 Startup Timer 4.1 ms SHDN Logic Input High Voltage V V = 2.7V to 5.5V 1.4 V IH IN V V = 2.7V to 5.5V 0.6 V SHDN Logic Input Low Voltage IL IN Shutdown Logic Input Current I SHDN = IN or GND -1 1 A SHDN 2 MAX1730