R1205x Series


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The R1205x Series are CMOS-based PWM control type step-up DC/DC converter ICs with low supply current.
Each of these ICs consists of an NMOS FET, a diode, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an under voltage lockout circuit (UVLO), an over-voltage protection circuit (OVP), a soft-start circuit, a Maxduty limit circuit, and a thermal shutdown protection circuit. This step-up DC/DC converter can be easily built with a few external components such as a coil, a resistor, and a capacitor.
As the protection functions, the R1205x Series have a Lx peak current limit function, an over voltage protection (OVP) function, an under voltage lock out (UVLO) function and a thermal shutdown function.

The R1205x Series present the R1205x8xxA version that is optimized for the constant voltage power source, and the R1205x8xxB/C version that is optimized for driving the white LED with the constant current. The R1205x8xxB/C is an adjustable version that can change the LED brightness dynamically by using a 200Hz to 300kHz PWM signal toward the CE pin.

The R1205x Series are available in DFN1616-6B and TSOT-23-6 packages.

Input Voltage Range 2.3V to 5.5V (R1205x8xxA)
1.8V to 5.5V (R1205x8xxB/C)
Supply Current Typ. 800µA
Standby Current Max. 5µA
Feedback Voltage 1.0V±1.5% (R1205x8xxA)
0.2V±10mV (R1205x8xxB)
0.4V±10mV (R1205x8xxC)
Oscillator Frequency Typ. 1.2MHz
Maximum Duty Cycle Typ. 91%
UVLO Function Typ.2.0V (Hys.Typ.0.2V) (R1205x8xxA)
Typ.1.6V (Hys.Typ.0.1V) (R1205x8xxB/C)
Lx Current Limit Function Select from 350mA, 700mA
Over Voltage Protection Typ. 25V
LED dimming control (R1205x8xxB/C) by external PWM signal (Frequency 200Hz to 300kHz)
Thermal Protection Function Typ.150ºC(Hys.Typ.50ºC)
Switch ON Resistance Typ. 1.35Ω
Packages DFN1616-6B, TSOT-23-6
Ceramic capacitors are recommended  
  • Constant Voltage Power Source for portable equipment
  • OLED power supply for portable equipment
  • White LED Backlight for portable equipment

Data Sheet Flyer Design Guide
R1205x Series R1205x / R1207N Series R1205x Series
Package Info. Mark Info. Quality Assurance Data
DFN1616-6B R1205L Reliability
TSOT-23-6 R1205N Reliability

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