VFM STEP-UP DC/DC
CONVERTER CONTROLLER
RN5RY202
NO.EA-042-0006
OUTLINE
The RN5RY202 Series are VFM (chopper) Control ICs for step-up DC/DC converter with an external power transis-
tor featuring high output voltage accuracy and low supply current by CMOS process. Each of the RN5RY202
Series ICs consists of a voltage reference unit, an error amplifier, an oscillator, a VFM control circuit and feed back
resistors.
Output voltage is fixed at 2V in the IC.
A low ripple, high efficiency step-up DC/DC converter can be constructed by simply adding an inductor, a diode, a
capacitor, and a drive transistor and feed back resistors.
Although the series have no CE pins unlike RN5RY
××
1A, high voltage (V
OUT
=30V) can be also output by using
external feed back resistors.
FEATURES
• Low Supply Current ............................................................................TYP. 3µA
• Low Temperature-Drift Coefficient of Output Voltage ...................TYP. ±50ppm/˚C
• High Accuracy Output Voltage .........................................................±2.5%
• Low Oscillation Start-up Voltage (no load) ......................................MAX. 0.8V
• Any output voltage can be set with external resistors
• Small Package SOT-23-5 (Mini-Mold)
APPLICATIONS
• Constant voltage power source for battery-powered instruments.
• Constant power source for cameras, camcorders, pagers, and other hand-held communication tools.
• Constant power source for devices that require higher voltages than battery voltages.
BLOCK DIAGRAM
V
DD
2
Oscillator
3
V
OUT
5
EXT
Output
Buffer
–
+
Vref
1
GND
1
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
