RICOH RN5RK SERIES VFM STEP-UP DC DC CONVERTER User Guide and Data Sheet
Summary
The RN5RK series offers advanced VFM (Chopper) Step-up DC/DC converter ICs designed for efficient power solutions in portable electronics. These CMOS-based converters provide ultra-low supply current and high output voltage accuracy using minimal external components (inductor, diode, capacitor). The manual serves as a comprehensive guide, detailing pin configurations, electrical characteristics, applications—such as battery-powered cameras and communication equipment—and providing selection guidance for varying output voltages and driver options. Ideal for engineers developing energy-efficient power sources requiring stable DC/DC conversion across various demanding applications.
Page 1 Text Content
RN5RK SERIES
VFM STEP-UP DC/DC CONVERTER
NO.EA-045-111124
OUTLINE 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 m A and several hundreds m A. 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.
FEATURES • 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=10m A) • Low Ripple and Low Noise • Including a Driver Transistor with Low ON Resistance........Only RN5RKxx1A/xx1B • Low Start-up Voltage............................................................Max.0.9V
APPLICATIONS • 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.
Page Summary Contents For RICOH RN5RK SERIES VFM STEP-UP DC DC CONVERTER User Guide and Data Sheet
Manual Details
| Brand | Ricoh |
|---|---|
| Pages | 23 |
| File Size | 354.13 KB |
| Published | May 31, 2026 |
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Frequently Asked Questions
What external components are needed to build a step-up converter with this IC?
It requires only three external components: an inductor, a diode, and a capacitor.
Which RN5RK series should I use for large output currents?
The RN5RKxx2A is recommended for output currents between tens mA and several hundred mA because it uses an external drive pin (EXT).
What is the typical standby current draw?
The standby current is typically 0μA, which can be minimized using the chip enable function.
What is the supported output voltage range?
The converter supports a wide output voltage range from 2.0V to 5.5V.