R1242 Series
3A 30V Input PWM Step-down DC/DC Converter with Synchronous Rectifier Ext. Low-side Tr.

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  • Description

    The R1242 Series are 30V input, CMOS-based PWM step-down DC/DC converters featuring 3A* output current. R1242 includes a soft start circuit and a latch or fold-back protection circuit. By simply using an inductor, resistors, a low side switch (FET), and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. Due to current mode PWM control, the R1242 provides a fast response and high efficiency.

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

  • Spec
    Input Voltage Range 5.0 V to 30.0 V (32.0 V)
    Operating Temperature Range -40°C to 85°C (125°C)
    Supply Current Typ. 800 µA (VIN = 30 V, SET VFB = 1.0 V)
    Standby Current Typ. 0 µA (VIN = 30 V, CE = “L”)
    Output Voltage Range Externally Adjustable: 0.8 V to 15.0 V
    Feedback Voltage 0.8 V
    Feedback Voltage Accuracy ±12 mV
    Output Current 3 A
    Oscillator Frequency Externally Adjustable(Ver.A/B): 330 kHz to 1 MHz
    330 kHz (C/D), 500 kHz (E/F), 1 MHz (G/H)
    Maximum Duty Cycle Typ. 88%
    Package HSOP-8E

    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
    • R1242S001A/B Typical Application

      R1242S001A/B Typical Application

      (VOUT=3.3V, 1MHz)

    • R1242S Efficiency vs. Output Current

      R1242S 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.

Download Datasheet

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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