Global

RN5RK Series

VFM STEP-UP DC/DC CONVERTER

Data Sheet / Flyer

The RN5RKxx1A/xx1B/xx2A Series are CMOS-based VFM (Chopper) Step-up DC/DC converter ICs with ultra low supply current and high output voltage accuracy.

Each of the RN5RKxx1A/xx1B consists of an oscillator, a VFM control circuit, a driver transistor to have low ON resistance (Lx switch), a reference voltage unit, a high speed comparator, resistors for voltage detection, an Lx switch protection circuit and an internal chip enable circuit. A low ripple, high efficiency step-up DC/DC converter can be composed of this RN5RKxx1A/xx1B with only three external components: an inductor, a diode and a capacitor.

The RN5RKxx2A uses the same chip as what is employed in the RN5RKxx1A/1B IC and has a drive pin (EXT) for an external transistor instead of an Lx pin. As it is possible to load a large output current with a power transistor which has a low saturation voltage, RN5RKxx2A IC is recommendable to users who need an output current as large as between several tens mA and several hundreds mA.

Using the chip enable function, it is possible to make the supply current on standby minimized.

Since the package for these ICs is SOT-23-5, high density mounting of the ICs on board is possible.

Small Number of External Components	Only an inductor, a diode and a capacitor (RN5RKxx1A/xx1B)
Standby Current	Typ. 0µA
Low Temperature-Drift Coefficient of Output Voltage	Typ. ±100ppm/°C
Output Voltage Range	2.0V to 5.5V
Two Kinds of Duty Ratio	77% (xx1A, xx2A)/ 55% (xx1B)
High Output Voltage Accuracy	±2.5%
Small Packages	SOT-23-5
High Efficiency	Typ. 85% (RN5RK301B, VIN=2V, IOUT=10mA)
Low Ripple and Low Noise
Including a Driver Transistor with Low ON Resistance	Only RN5RKxx1A/xx1B
Low Start-up Voltage	Max.0.9V

・Power source for battery-powered equipment.
・Power source for cameras, camcorders, VCRs, and hand-held communication equipment.
・Power source for those appliances which require higher cell voltage than that of batteries.