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Wide 6 V to 75 V input voltage synchronous buck controller

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Product overview


The 6 V to 75 V wide input voltage range L3751 synchronous buck controller features extreme voltage conversion ratio over switching frequency range (100 kHz - 1 MHz) thanks to 40 nsec minimum conduction time.

The diode emulation (DEM) implements pulse skipping mode that maximizes the efficiency at light-load giving controlled output voltage ripple. The forced PWM (FPWM) over the load range makes the switching frequency constant and minimizes the output voltage ripple.

The Power Good open collector output validates the regulated output voltage for monitoring and it is useful to implement output voltage sequencing for digital ICs during the power-up phase.

An embedded gate driver minimizes the number of external components and it is designed for standard VTH MOSFET.

Embedded protections–output overcurrent, input voltage UVLO, internal voltage monitoring, thermal shutdown - feature controlled and safe operation for critical environments in telecom, networking and industrial applications.

The device is available in a QFN 20 leads 3.5 x 4.5 mm package with wettable flanks.

  • All features

    • Wide 6 V to 75 V input voltage range
    • Adjustable output voltage from 0.8 V to 60 V
    • 100 kHz - 1 MHz switching frequency range
    • 40 nsec minimum on-time for extreme duty ratio
    • Low dropout operation during line transient
    • Adjustable soft-start or input voltage tracking
    • Pulse skipping or forced PWM operation at light load
    • Synchronization
    • Adjustable precision enable
    • Power Good open collector output validates VOUT
    • 7.5 V gate drivers for standard VTH MOSFETs
    • Constant current protection with hiccup mode
    • Precision or lossless programmable current sensing
    • Improved line transient response
    • Input voltage undervoltage lockout
    • Internal voltage monitoring
    • Thermal protection
    • Operating junction temperature range: -40 °C to 150 °C


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Technical Bulletin
L3751: Wide 6V to 75V Input Voltage Synchronous Buck Controller

EDA Symbols, Footprints and 3D Models

STMicroelectronics - L3751

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Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
QFN 3.5X4.5X1.0 20L PITCH 0.50 Industrial Ecopack2



QFN 3.5X4.5X1.0 20L PITCH 0.50

Material Declaration**:


Marketing Status



QFN 3.5X4.5X1.0 20L PITCH 0.50



RoHS Compliance Grade


(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

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