R1244N Series

1.2A* 30V Input PWM Step-down DC/DC Converter


The R1244N Series are 30V input, CMOS-based PWM step-down DC/DC converters featuring 1.2A* output current. R1244N include a fold-back protection circuit. By simply using an inductor, resistors, a diode, and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. Due to current mode PWM control, the R1244N provide a fast response and high efficiency. Ceramic output capacitors can be used. Two different pin layout of SOT-23-6W package as R1240N and R1244N are available.

Supply Current (IDD)
Typ. 500µA (No switching)
Standby Current (Istandby)
Max. 5µA (CE="L")
Input Voltage Range (VIN)
4.5V to 30.0V
Output Voltage Range (VOUT)
0.8V to 15.0V (Externally adjustable)
Feedback voltage : 0.8V)
Feedback Voltage Accuracy
± 12mV
Output Current (IOUT)
Oscillator Frequency (fosc)
Oscillator Maximum Duty Cycle (Maxduty)
R1240x : Min. 75%, Typ. 85%
R1244N : Typ. 85%
Minimum ON Time (tMIN)
UVLO Detect Voltage (VUVLO)
Typ. 3.8V
Soft Start Time (tstart)
Typ. 0.4ms
High Side Switch Limit Current
Typ. 2A
Thermal Shutdown Circuit
Stops at 160°C.
Fold-back Protection Circuit
Fold-back frequency
Typ. 310kHz (B Version)
Packages SOT-23-6W

*)This is an approximate value, because output current depending on conditions and external parts.

  • Power source for digital home appliances such as digital TVs and DVD players
  • Power source for office automation equipment such as printers and fax machines
  • Power source for hand-held communication equipment, cameras, and VCRs
  • Power source for battery-powered equipment

Data Sheet Flyer Package Info. Mark Info. Quality Assurance Data
R1240x / R1244N
SOT-23-6W to be prepared Reliability

All PDF files are less than 1MB unless otherwise stated.

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