OUTLINE

The RH5RH××1A/××2B/××3B Series are PWM Step-up DC/DC converter ICs by CMOS process. The RH5RH××1A IC consists of an oscillator, a PWM control circuit, a driver transistor (Lx switch), a reference voltage unit, an error amplifier, a phase compensation circuit, resistors for voltage detection, a soft-start circuit, and an Lx switch protection circuit. A low ripple, high efficiency step-up DC/DC converter can be constructed of this RH5RH××1A IC with only three external components, that is, an inductor, a diode and a capacitor. These RH5RH××1A/××2B/××3B ICs can achieve ultra-low supply current (no load) –TYP. 15µA –by a new ly developed PWM control circuit, equivalent to the low supply current of a VFM (chopper) Step-up DC/DC converter.

FEATURES

• Small Number of External Components ..........Only an inductor, a diode and a capacitor(RH5RH××1A)

• Low Supply Current........................................... TYP. 15µA (RH5RH301A)

• Low Ripple and Low Noise

• Low Start-up Voltage (when the output current is 1mA)..................MAX. 0.9V

• High Output Voltage Accuracy..........................±2.5

• High Efficiency...................................................TYP. 85

• Low Temperature-Drift Coefficient of Output Voltage......................TYP. ±50 ppm/˚C

• Soft-Start.............................................................MIN. 500µs

• Small Packages...................................................SOT-89 (RH5RH××1A, RH5RH××2B), SOT-89-5 (RH5RH××3B)