RV5VH Datasheet, PDF (47/47 Pages) RICOH electronics devices division – DC/DC CONVERTER CONTROLLER

RV5VH3××
APPLICATION HINTS
When using these ICs, be sure to take care of the following points.
• Set external components as close as possible to the IC and minimize the connection between the
components and the IC. In particular, when an external component is connected to VOUT Pin, make
minimum connection with the capacitor.
• Make sufficient grounding. A large current flows through GND Pin byswitching. When the impedance
of the GND connection is high, the potential within the IC is varied by switching current. This may
result in unstableoperation of the IC.
• Use capacitor with good high frequency characteristics such as tantalum capacitor, aluminium
electrolytic capacitor and ceramic capacitor. We recommend the use of a capacitor with an allowable
voltage which is at least three times the output set voltage. This is because there may be the case
where a spike-shaped high voltage is generated by the inductor when Lx transistor is turned OFF.
• Take the utmost care when choosing an inductor. Namely, choose such an inductor that has
sufficiently small d.c. resistance and large allowable current, and hardly reaches magnetic saturation.
When the inductance value of the inductor is small, there may be the case where ILX exceeds the
absolute maximum ratings at the maximum load. Use an inductor with an appropriate inductance. (See
OUTPUT CURRENT and SELECTION OF PERIPHERAL COMPONENTS sections.)
• Use a diode of a Schottky type with high switching speed, and also take care of the rated current. (See
OUTPUT CURRENT and SELECTION OF PERIPHERAL COMPONENTS sections.)
The performance of power source circuits using these ICs largely depends upon the peripheral components. Take
the utmost care in the selection of the peripheral components. In particular, design the peripheral circuits in such
a manner that the values such as voltage, current and power of each component, PCB patterns and the IC do not
exceed their respective rated values.
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