NJW4138 Series
Internal 45V MOSFET Switching Regulator IC for Capacitor Charge Boost Converter

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  • Description

    The NJW4138 is a step up switching regulator with 45V, 1.75A power MOSFET. The NJW4138 has a current mode control, a high frequency oscillating over a wide operating voltage range and an internal phase compensation circuit, so that it provides boost applications with a few external parts. The NJW4138 has built-in overcurrent protection for Pulse-by-Pulse, it is suitable for charging the backup capacitor.


    • Capacitor Charge
    • Power supply for VFD
    • Low power boost application

  • Spec
    Input Voltage Range 4.5 V to 40 V (45 V)
    Operating Temperature Range -40°C to 125°C
    Supply Current Typ. 3500 µA
    Standby Current 1 (max.) µA
    Output Voltage Range 4.5 V to 38 V
    Output Voltage Accuracy ± 1 %
    Output Current Switching Current 1750 mA
    Oscillator Frequency 2MHz typ. (C ver.)
    Package SOT-89-5-2
    Control Current Mode Control / PWM Control
    Function Standby Function
    Soft Start Function (10ms typ.)
    Over Current Protection (Pulse-by-Pulse type)
    Thermal Shutdown Protection
    Note Built-in Compensation Circuit
    UVLO (Under Voltage Lockout)
    External Clock Synchronization
    Correspond to Ceramic Capacitor (MLCC)

    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
    • Related Links

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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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