RP505 Series
1A PWM/VFM Step-down DC/DC Converter with Synchronous Rectifier

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  • Description

    The RP505 Series are low supply current CMOS-based PWM/VFM step-down DC/DC converters with synchronous rectifier. RP505 can be selected from two control types by input signal to the MODE pin - forced PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. The xx1A/B version with an internally fixed output voltage type and the 001C version with an externally adjustable output voltage type are available.

    RP505 includes a soft start circuit, an under-voltage lockout circuit (UVLO), thermal shutdown circuit and a latch protection circuit. By simply using an inductor and capacitors (and resistors) as external components, a high-efficiency step-down DC/DC converter can be easily configured. The small inductor (2.2µH) and output capacitor (10µF) can be used by the switching of 2.25MHz. A 2mm square compact DFN(PL)2020-8 package is available.

  • Spec
    Input Voltage Range 2.3 V to 5.5 V (6.5 V)
    Operating Temperature Range -40°C to 85°C (125°C)
    Supply Current Typ. 40 µA (VFM, no load)
    Standby Current Typ. 0 µA
    Output Voltage Range Internally Fixed Ver.: 0.6 V to 3.3 V (0.1 V step)
    Externally Adjustable Ver.: 0.8 V to 3.3 V
    Output Voltage Accuracy ±1.5% (VOUT ≥ 1.2 V, Ta = 25°C)
    ±18 mV (VOUT < 1.2 V)
    Output Voltage Temperature Coefficient ±100 ppm/°C
    Feedback Voltage 0.6 V
    Feedback Voltage Accuracy ±9 mV
    Feedback Voltage Temperature Coefficient ±100 ppm/°C
    Output Current 1 A
    Driver ON-resistance Pch: Typ. 0.23 Ω, Nch: Typ. 0.20 Ω (VIN = 3.6 V)
    Oscillator Frequency Typ. 2.25 MHz
    Maximum Duty Cycle Min. 100%
    Package DFN(PL)2020-8

    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
    • RP505Kxx1A/B Typical Application

      RP505Kxx1A/B Typical Application

    • RP505K001C Typical Application

      RP505K001C Typical Application

    • RP505K331x Efficiency vs. Output Current

      RP505K331x Efficiency vs. Output Current

    • 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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