R1223N Series

PWM/VFM step-down DC/DC Controller

Data Sheet / Flyer
Data Sheet * Flyer

The R1223N Series are CMOS-based PWM step-down DC/DC Converter controllers with low supply current.

Each of these ICs consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a soft-start circuit, a protection circuit, a PWM/VFM alternative circuit, a chip enable circuit, and resistors for voltage detection. A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC with only four external components, or a power-transistor, an inductor, a diode and a capacitor.

With a PWM/VFM alternative circuit, when the load current is small, the operation is automatically switching into the VFM oscillator from PWM oscillator, therefore the efficiency at small load current is improved. The R1223NxxxB type, which is without a PWM/VFM alternative circuit, is also available.

If the term of maximum duty cycle keeps on a certain time, the embedded protection circuit works. There are two types of protection function. One is latch-type protection circuit, and it works to latch an external Power MOSFET with keeping it disable. To release the condition of protection, after disable this IC with a chip enable circuit, enable it again, or restart this IC with power-on. The other is Reset-type protection circuit, and it works to restart the operation with soft-start and repeat this operation until maximum duty cycle condition is released.
Either of these protection circuits can be designated by users' request.

Input Voltage Range 2.3V to 13.2V
Output Voltage Range 1.5V to 5.0V (0.1V step)
Output Voltage Accuracy ±2.0%
Oscillator Frequency 300kHz, 500kHz
High Efficiency Typ. 90%
Standby Current Typ. 0μA
Temperature-Drift Coefficient of Output Voltage Typ. ±100ppm/°C
Built-in Soft-start Circuit
Built-in Latch-type or Reset type Protection Circuit
Package SOT-23-5
  • Power source for hand-held communication equipment, cameras, video instruments such as VCRs, camcorders.
  • Power source for battery-powered equipment.
  • Power source for household electrical appliances.
Data Sheet Flyer Package Info. Mark Info. Quality Assurance Data
R1223N Series R1223N Series SOT-23-5 R1223N to be prepared

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