RP401x SERIES HIGH EFFICIENCY, SMALL PACKAGES, STEP-UP DC/DC CONVERTERS NO.EA-260-160812 OUTLINE RP401x Series are high efficiency, step-up DC/DC converter ICs packaged in compact 5pin SOT23-5 or 6pin DFN(PLP)1820-6. This IC can start up from low voltage (Typ.0.6V), therefore, it is suitable for using with single or 2 serial alkaline batteries, or a nickel-metal-hydride (NiMH) battery, or one-cell Lithium-ion (Li+) battery. This IC consists of an oscillator, a reference voltage unit with soft start, a chip enable circuit, an error amplifier, phase compensation circuits, a slope circuit, a PWM control circuit, a start-up circuit, a PWM/VFM mode control circuit, internal switches and a protection circuit. A low ripple high efficiency step-up DC/DC converter can be composed of the RP401x with only an inductor, a diode, (resisters for adjustable type), and capacitors. The output voltage of the RP401K001s is adjustable, and others are fixed internally. The output voltage range is from 1.8V to 5.5V. RP401Kxx1A/B series have a MODE pin to alternate between PWM fix and PWM/VFM automatic shift to improve the efficiency at light load. If MODE pin is set, the mode is PWM fix, and when the MODE pin is set, PWM/VFM automatic shift. The RP401xxx1C and D do not have MODE pin. The RP401xxx1C is PWM/PFM alternative type, and the RP401xxx1D is PWM fixed type. FEATURES Low Start-up Voltage guaranteed Typ. 0.6V Input Voltage Range 0.6V ~ 5.5V High Efficiency 86% (100mA / 3.3V, V = 1.5V, 25C) IN Output current 500mA / 1.8V (V = 1.5V) / 5.0V (V = 3.3V) IN IN Built-in Lx switch NMOS: 0.4 (V = 3.3V, 25C) OUT PWM Oscillator Frequency 1.2MHz Output Voltage Range Fixed type: 1.8V to 5.5V with 0.1V Stepwise Adjustable: 1.8V ~ 5.5V (Recommendation range of output voltage) Lx peak current limit function Typ. 1.0A Latch protection delay time 3.3ms (Only applied to A version) Small Packages DFN(PLP)1820-6, SOT23-5 APPLICATIONS MP3 players, PDA, cellular phones Digital Still Cameras LCD Bias Supplies Portable blood pressure meter Wireless Handset GPS 1 RP401x BLOCK DIAGRAMS Fixed output RP401Kxx1A/B V IN VFM STARTUP CURRENT OSCILLATOR LX CONTROL CIRCUIT PROTECTION VREF SWITCHING PWM CONTROL E/A SOFT CURRENT START FEEDBACK RAMP COMPENSATION CHIP CE ENABLE VOUT MODE CONTROL MODE GND Adjustable output type: RP401K001C/D V IN VFM CURRENT STARTUP OSCILLATOR LX CONTROL* CIRCUIT PROTECTION VREF SWITCHING PWM CONTROL E/A SOFT CURRENT START FEEDBACK RAMP COMPENSATION CHIP CE ENABLE VOUT VFB GND *) Applied to PWM/VFM automatic shift, RP401K001C only. 2