R1211N Series

PWM Step-up DC/DC Controller for Automotive Applications


Data Sheet

Data Sheet

The R1211x Series are CMOS-based PWM step-up DC/DC converter controllers with low supply current.
Each of the R1211x Series consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A low ripple, high efficiency step-up DC/DC converter can be composed of this IC with some external components, or an inductor, a diode, a power MOSFET, divider resisters, and capacitors. Phase compensation has been made internally in this device, and it has stand-by mode. Max duty cycle is internally fixed typically at 90%.
Soft start function is built-in, and Soft-starting time is set typically at 9ms (B, 700kHz version) or 10.5ms (D, 300kHz version). As for the protection circuit, after the soft-starting time, if the maximum duty cycle is continued for a certain period, the R1211x Series latch the external driver with its off state, or Latch-type protection circuit works.
The delay time for latch the state can be set with an external capacitor. To release the protection circuit, restart with power-on (Voltage supplier is equal or less than UVLO detector threshold level), or once after making the circuit be stand-by with chip enable pin and enable the circuit again.


Input Voltage Range (Maximum Rating) 2.5V to 6.0V (6.5V)
Built-in Latch-type Protection Circuit Protection Delay Time can be set with an external capacitor
Oscillator Frequency (PWM control) 300kHz, 700kHz
Maximum Duty Cycle Typ. 90%
Standby Current Typ. 0µA
Feedback Voltage 1.0V
Feedback Voltage Accuracy ±1.5%
UVLO Threshold level Typ. 2.2V (Hysteresis Typ. 0.13V)
Feedback Voltage Temperature Coefficient Typ. ±150ppm/°C
Package SOT-23-6W


  • Power source for accessories such as car audios, car navigation systems, and ETC systems

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Data Sheet Package Quality Assurance Data Suffix Composition & Content*1
R1211x Series SOT-23-6W Reliability -AE Sn (Sn: 100%)
  • *1The composition of the product cannot be specified.

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