Diodes Incorporated

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U DFN2020 6 Type F

Image shown is for reference only. Actual package may vary. Refer to the product data sheet for package details.

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AH5794 (Not Recommended for new design)

NRND = Not Recommended for New Design

Single Phase 3V/5V BLDC All-In-One Fan and Motor Driver with Low Rdson Softswitch and Thermal Shutdown

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The AH5794 is a single chip solution for driving single-coil brushless direct current (BLDC) fans and motors. The integrated full-bridge driver output stage uses soft switching to minimize audible switching noise and electromagnetic interference (EMI) providing a low noise solution. Low operating voltage down to 1.8V allows motor speed to be control°C by varying the supply voltage. To help protect the motor coil, the AH5794 provides Rotor Lock Protection which shuts down the output drive if rotor lock is detected. The device automatically re-starts when the rotor lock is removed. Over temperature shutdown provides thermal protection for the device. A Tachometer output is provided by open-drain Frequency Generator (FG) Pin which allows external interface to monitor motor rotation or speed. The FG output is the magnetic change frequency.


  • Supports single-coil full-wave BLDC fan drivers
  • Built-in Hall sensor and input amplifier
  • Operating voltage: 1.8V to 6V
  • VDD voltage speed control
  • Soft switching for low noise DC fan motor applications
  • Rotor Lock Protection (Lock detection, output shutdown and automatic re-start)
  • Thermal protection
  • Tachometer (FG) output
  • No external timing capacitor - Reduces the numbers of external components required
  • Low profile package: TSOT26 and U-DFN2020C-6
  • Halogen and Antimony free “Green” packages.
  • Lead Free Finish/ RoHS Compliant
  • Application(s)

  • 3V/ 3.3V/ 5V BLDC Cooling Fans
  • Netbook/ Notebook BLDC fans
  • Instruments cooling fans
  • Low Voltage/ Low Power BLDC Motors
  • Product Specifications

    Product Parameters

    Average OutputDrive Current (mA) 1000
    Frequency Generator (FG) and Rotation Detect FG
    Lock Detect, Shut-Down and Auto Start -
    Operating Ambient Temperature (°C) -40 to 105
    Operating Point Bop Gauss (Max) 50
    Operating Point Bop Gauss (Min) 10
    Operating Point Bop Gauss (Typ) 25
    Operating Voltage (V) 1.8 to 6
    Peak Output Current (mA) 300, 500
    Release Point Brp Gauss (Max) -10
    Release Point Brp Gauss (Min) -50
    Release Point Brp Gauss (Typ) -25
    Soft-Switch Yes
    Speed Control VDD
    SupplyCurrent (mA) 2.2
    Typical Total RDS(ON)(NMOS and PMOS Combined) 1 @ 5V

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    Technical Documents

    Recommended Soldering Techniques


    Product Change Notices (PCNs)

    A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

    PCN # Issue Date Implementation Date Subject
    PCN-2594 2022-08-31 2023-02-28 Device End of Life (EOL)