Diodes Incorporated
U QFN4040 16 SWP

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3.8V TO 60V Input Automotive Grade, 3A Low IQ Synchronous Buck Converter

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The DIODES™ AP66300Q is an adjustable switching frequency internal compensated synchronous DC-DC buck converter with a default internal frequency of 500kHz. The device fully integrates a 120mΩ high-side power MOSFET and a 55mΩ low-side power MOSFET to provide high-efficiency step-down DC-DC conversion. 

The device enables a continuous load current of up to 3A with efficiency as high as 95% in enhanced biased. It features current mode control operation, which enables easy loop stabilization supporting a wide range of output capacitive loads.

The AP66300Q simplifies board layout and reduces space requirements with its high level of integration and minimal need for external components, making it ideal for distributed power architectures.

The AP66300Q is available in the standard Green U-QFN4040-16/SWP (Type UXB) package.


  • Qualified for Automotive Applications
  • AEC-Q100 Qualified with the Following Results
    • Device Temperature Grade 1: -40°C to +125°C TA
    • Device HBM ESD Classification Level H1C
    • Device CDM ESD Classification Level C3B
  • VIN8 to 60V
  • 3A Continuous Output Current
  • VOUT Adjustable from 0.8V to 50V
  • Enhanced Efficiency Mode with Bias
  • Adjustable Switching Frequency; 500kHz Default Frequency
  • Start-up with Pre-biased Output
  • External Soft-Start with Tracking – Sequential, Ratiometric, or Absolute; Default Internal Soft-Start of 1.7ms
  • Enable Pin with 5% tolerance
  • Soft Discharge
  • ±5% Power Good Detection with Internal Pull-up Resistor
  • Overcurrent Protection (OCP) with Hiccup
  • Thermal Protection
  • Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
  • Halogen and Antimony Free. “Green” Device (Note 3)
  • The AP66300Q is suitable for automotive applications requiring specific change control; this part is AEC-Q100 qualified, PPAP capable, and manufactured in IATF 16949 certified facilities.



  • General-purpose point-of-load DC/DC power conversion
  • Automotive infotainments
  • Telecommunication systems
  • Distributed power systems
  • Home audio devices
  • Consumer electronics
  • Network systems
  • FPGA, DSP, and ASIC supplies
  • Green electronics

Product Specifications

Product Parameters

Compliance(Only Automotive supports PPAP) Automotive
Type Buck
Minimum Input Voltage (V) 3.8
Maximum Input Voltage (V) 60
Output Current (A) 3
Minimum Output Voltage (V) 0.8
Maximum Output Voltage (V) 50
Quiescent Current Typ (µA) 43
Shutdown Current Typ (µA) 2.2
Frequency Typ (kHz) 300/500/2500
HS RDS(ON) (mΩ) 120
LS RDS(ON) (mΩ) 55
Features Enhanced Efficiency Mode with Bias, Adjustable Switching Frequency, 500kHz Default Frequency, Start-up with Pre-biased Output, External Soft-Start with Tracking – Sequential, Ratiometric, or Absolute, Default Internal Soft-Start of 1.7ms, Enable Pin with 5

Technical Documents

Evaluation Boards and User Guides

Recommended Soldering Techniques