Diodes Incorporated

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Automotive Dual Hall Effect Latch with Speed & Direction Outputs Integrated Self-diagnostics

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The AH3975Q/AH3976Q/AH3977Q/AH3978Q is an AEC-Q100 qualified high voltage dual Hall-effect sensor designed for the applications that require accurate speed and direction sensing. To support wide range of demanding applications, the design has been optimized to operate over the supply range of 2.7V to 27V. With chopper stabilized architecture and an internal bandgap regulator to provide temperature compensated supply for internal circuits, the AH3975Q/AH3976Q/AH3977Q provides speed and direction outputs, while AH3978Q provides two independent outputs at Q1 and Q2.

For robustness and protection, the device has a reverse blocking diode with a Zener clamp on the supply. The built-in thermal protection also shuts down the chip if temperature rises to an abnormal value, and it will automatically restart the chip once the junction temperature drops below the safe value. The device is integrated with self-diagnostics which monitor internal blocks, and it will enter safe mode when error is detected.

In the occasion of a supply voltage drop to minimum threshold point, undervoltage lockout protection would be triggered to freeze the device, which prevents the electrical malfunction from affecting the next magnetic measurement circuits, and the output current state updated is always based on the proper accurate measurement result.  


  • Dual Latch Hall Operation with Dual Outputs (AH3978Q) or Speed & Direction Output (AH3975Q/AH3976Q/AH3977Q)
  • Wide Supply Voltage Operation: 2.7V to 27V
  • Chopper Stabilized Design Provides
    • Superior Temperature Stability
    • Minimal Switch Point Drift
    • Enhanced Immunity to Stress
  • Battery Polarity Reverse Connection Protection
  • Transient Spike Voltage Protection
  • Overtemperature Shutdown and Auto-Restart
  • UVLO Protection
  • High ESD Rating: HBM = 5kV, CDM = 2kV
  • AEC-Q100 Grade 0 Qualified
  • Ready for ISO 26262
  • Built-in Self-Diagnostics for Functional Safety Requirements
  • Temperature Range: -40°C to +150°C
  • Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
  • Halogen and Antimony Free. “Green” Device (Note 3)
  • The AH3975Q/AH3976Q/AH3977Q/AH3978Q is suitable for automotive applications requiring specific change control; this part is AEC-Q100 qualified, PPAP capable, and manufactured in IATF16949 certified facilities. https://www.diodes.com/quality/product-definitions/


  • Power closures with anti-pinch features
  • Rotation speed & direction detection
  • Linear speed & direction detection
  • Angular position detection
  • Knob controls

Product Specifications

Product Parameters

Compliance(Only Automotive supports PPAP) Automotive
AEC Qualified Yes
Type Latch
Outputs Dual Speed & Direction
Output Type Open Drain
Key Feature ISO 26262-Ready, Diagnostics
Operating Voltage (V) 2.7 to 27
Average Supply Current (mA) 4.7
Min Operating Point Bop (Bops +ve/ Bopn -ve) (Gauss) -10
Typ Operating Point Bop (Bops +ve/ Bopn -ve) (Gauss) 10
Max Operating Point Bop (Bops +ve/ Bopn -ve) (Gauss) 30
Min Release Point Brp (Brps +ve/ Brpn -ve) (Gauss) -30
Typ Release Point Brp (Brps +ve/ Brpn -ve) (Gauss) -10
Max Release Point Brp (Brps +ve/ Brpn -ve) (Gauss) 10
Operating Ambient Temperature (°C) -40 to 150

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