R1205 Series
PWM Step-up DC/DC Converter for White LED/PMOLED and General Use

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  • Description

    The R1205 Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs and PMOLED with constant current. There are two types. The A version is optimized for the general use or the drive of PMOLED, and the B/C version is optimized for the serial drive of white LED with constant current. The R1205 includes a diode, an under-voltage lockout circuit (UVLO), a soft-start circuit, and an over-voltage protection circuit (OVP), a thermal shutdown circuit. By simply using an inductor, resistors, and capacitors as external components, white LEDs can be driven with high efficiency. The B/C version can set the LED current with feedback resistor (R1). The brightness of the LEDs and the soft-start time can be adjusted by applying a PWM signal (200Hz to 300kHz) to the CE pin. Two different pin layout of TSOT-23-6 package as R1205N and R1207N are available.

  • Spec
    Input Voltage Range 1.8 V to 5.5 V (6.5 V)
    Operating Temperature Range -40°C to 85°C (125°C)
    Supply Current Typ. 800 µA
    Standby Current Typ. 1 µA
    Output Voltage Range Externally Adjustable: Max. 24.2 V (0.1 V step)
    Feedback Voltage 1.0 V (R1205x8xxA)
    0.2 V (R1205x8xxB)
    0.4 V (R1205x8xxC)
    Feedback Voltage Accuracy ±15 mV (R1205x8xxA)
    ±10 mV (R1205x8xxB/C)
    Driver ON-resistance Typ. 1.35 Ω
    Oscillator Frequency Typ. 1.2 MHz
    Maximum Duty Cycle Typ. 91%
    Package DFN1616-6B, TSOT-23-6

    Protections / Functions

    TSD ILX OCP OVP UVLO OVLO Reverse Shutdown Soft Start SSCG PGOOD Auto Discharge Anti-ringing Sequencing Max Duty Ext. Phase LED Adjust
  • Technical
    • R1205x8xxA Typical Application

      R1205x8xxA Typical Application

    • R1205x8xxB/C Typical Application

      R1205x8xxB/C Typical Application

    • R1205N823A Efficiency vs. Output Current: VOUT=10V (10 µH)

      R1205N823A Efficiency vs. Output Current: VOUT=10V (10 µH)

    • R1205N823B/C Efficiency vs. Output Current: 6LEDs (10 µH)

      R1205N823B/C Efficiency vs. Output Current: 6LEDs (10 µH)

    • Related Links

      • Prime Designer

        Online Design Tool

        Registration to myNISD is required to use some of the functions, such as simulations.

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  • Quality &
    • Refer to the datasheets for the details on the product.
    • The package file or the datasheet includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and recommended land pattern.

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Functional Description

TSD Thermal Shutdown Function
ILX LX Current Limit Function
OCP Overcurrent Protection
OVP Overvoltage Protection
UVLO Undervoltage Lockout Protection
OVLO Overvoltage Lockout Protection
Reverse Reverse Current Protection Circuit
Shutdown Shutdown Function
Soft Start Soft Start Function
SSCG Spread Spectrum Clock Generator Function
PGOOD Power Good Output
Auto Discharge Auto Discharge Function
Anti-ringing Anti-ringing Switch Function
Sequencing Start-up Sequencing Control
Max Duty Maximum Duty Cycle
Ext. Phase Externally Adjustable Phase Compensation
LED Adjust LED High-speed Dimming Control

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