PWM Step-up DC/DC Converter

R1210N××1× Series

1

OUTLINE

The R1210N××1× Series are PWM step-up DC/DC Converter, with high accuracy, low supply current by CMOS

process.

Each of the R1210N××1× Series consists of an oscillator, a PWM circuit, a reference voltage unit, an error amplifier,

phase compensation circuit, resistors for voltage detection, a chip enable circuit. Further, includes a controller against

and an output voltage detector. R1210N××1A Series contain further a circuit for changeover oscillator frequency each.

A low ripple, high efficiency step-up DC/DC converter can be composed of this IC with only three external compo-

nents, or an inductor, a diode and a capacitor.

The R1210N Series can detect drastic change of output voltage with a circuit controller. The load transient re-

sponse is improved compared with current model, furthermore the R1210N××1A Series have another function, that is,

when the load current is small, oscillator frequency is decreased by a circuit for switching oscillator frequency from

TYP. 100kHz to 35kHz, therefore, supply current is reduced.

The built-in chip enable circuit can make the standby mode with ultra low quiescent current.

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

FEATURES

• External Components ................................................................. Only an inductor, a diode, and a capacitor

• Standby Current ......................................................................... TYP. 0µA

• Low Temperature-Drift Coefficient of Output Voltage.............. TYP. ±100ppm/°C

• Output Voltage............................................................................. Stepwise Setting with a step of 0.1V in the range of

2.2V to 6.0V (××1C/D)

2.2V to 3.5V (××1A)

• Two choices of Basic Oscillator Frequency................................ 100kHz (××1A/C), 180kHz (××1D)

• Small Package.............................................................................. SOT-23-5 (Mini-mold)

• High Efficiency ............................................................................ TYP. 88%

• Low Ripple, Low Noise

• Built-in a driver transistor with low on-resistance

• Start-up Voltage........................................................................... MAX. 0.9V

• Basic Frequency change-over circuit (only for ××1A type)....... from TYP. 100kHz to 35kHz