R5212D Datasheet, PDF (1/26 Pages) RICOH electronics devices division – Step-down DC/DC Converter with VR and Reset

R5212D SERIES
Step-down DC/DC Converter with VR and Reset
NO.EA-128-0510
OUTLINE
The R5212D is CMOS-based PWM step-down DC/DC converter combined with a voltage regulator (VR) and
a voltage detector (VD), with low supply current.
Each of these ICs consists of an oscillator, a PWM control circuit, a voltage reference unit, an error amplifier, a
soft-start circuit, a current limit circuit, a phase compensation circuit, a resistor net for voltage detect circuit, an
output driver transistor, and so on. A low ripple, high efficiency step-down DC/DC converter can be easily
composed of this IC with some external components, or an inductor, a diode, and capacitors.
The oscillator frequency is 1.2MHz, therefore small inductor and capacitor can be used with this IC. Further,
this IC equips the under voltage lockout function (UVLO). If the input voltage becomes equal or less than 2.35V
(Typ.), the output of DC/DC converter turns off. However, in the A/B version, embedded voltage regulator and
detector continue to operate. In the C/D version, LDO output also turns off and only the voltage detector is
working.
The voltage regulator consists of a voltage reference unit, a resistor net for voltage detect circuit, an error
amplifier, an output driver transistor, and so on.
The input source voltage of the built-in voltage regulator is VIN pin (A/B version) or VOUT1 pin, the output of
DC/DC converter (C/D version).
The built-in voltage detector supervises the input voltage and the output is N-channel open drain.
Power-on reset delay time is also included and internally set typically at 12ms (A/C version) or 50ms(B/D
version).
FEATURES
• Range of Input Voltage ............................. 3.0V~5.5V
• Built-in Soft-start Function (Typ. 1ms) and built-in power-on reset delay (Typ. 12ms or 50ms)
• Maximum Output Current...........................500mA (DC/DC), 200mA (VR)
• Accuracy Output Voltage .......................... ±2.0% (DC/DC and Voltage Regulator Output)
• Accuracy of voltage detector .................... ±2.5%
• Output Voltage (VR)(A/B Version) ............ Stepwise Setting with a step of 0.1V in the range of 2.0V to 3.6V
(C/D Version) ............ Stepwise Setting with a step of 0.1V in the range of 1.2V to 3.0V
• Output Voltage (DC/DC) (A/B Version) ..... Stepwise Setting with a step of 0.1V in the range of 1.2V to 3.6V
(C/D Version) ..... Stepwise Setting with a step of 0.1V in the range of 2.5V to 3.6V
• Output Voltage (VD).................................. Stepwise Setting with a step of 0.1V in the range of 3.0V to 4.5V
• Package .................................................... HSON-6 (t=0.9mm)
APPLICATIONS
• Power source for hand-held communication equipment, CD or DVD drives.
• Power source for battery-powered equipment.
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