Precision, Hall-Effect Angle Sensor IC with SPI, and SENT or PWM Outputs


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The A1338 is a 0° to 360° angle sensor IC that provides contactless high-resolution angular position information based on magnetic circular vertical Hall (CVH) technology. It has a system-on-chip (SoC) architecture that includes: a CVH front end, digital signal processing, digital SPI, and SENT or PWM outputs. It also includes on-chip EEPROM technology, capable of supporting up to 100 read/write cycles, for flexible end of line programming of calibration and configuration parameters. The A1338 is ideal for automotive applications requiring 0° to 360° angle measurements, such as electronic power steering (EPS), seatbelt motor position systems, rotary PRNDLs, and throttle systems.

The A1338 was designed with safety-critical application requirements in mind. It includes user-controlled on-chip logic built-in self-test (LBIST) and full signal path diagnostics to enable customers to determine if the IC is operating in a proper manner.

The A1338 supports a Low RPM mode for slower rate applications and a High RPM mode for high-speed applications. High RPM mode is for applications that require higher refresh rates to minimize error due to latency. Low RPM mode is for applications that require higher resolution operating at lower angular velocities.

The A1338 is available in single-die 14-pin TSSOP and a dual-die 24-pin TSSOP. Both packages are lead (Pb) free with 100% matte-tin leadframe plating.

  • Contactless 0° to 360° angle sensor IC, for angular position and rotation direction measurement
    • Circular Vertical Hall (CVH) technology provides a single-channel sensor system, with air gap independence
    • 12-bit resolution possible in Low RPM mode, 10-bit resolution in High RPM mode
    • Angle Refresh Rate (output rate) configurable between 25 and 3200 μs through EEPROM programming
    • Capable of sensing magnetic rotational speeds up to 7600 rpm, and up to 30,000 rpm with reduced accuracy
    • SPI (mode 3), and SENT (Single Edge Nibble Transmission) or PWM (Pulse-Width Modulation)*
    • SPI interface provides a robust communication protocol for fast angle readings*
    • SENT output supports four modes: SAEJ2716 (JAN2010) and Allegro proprietary options of Triggered SENT (TSENT), Sequential SENT (SSENT), and Addressable SENT (ASENT)*
    • Programmable via Manchester Encoding on the VCC line, reducing external wiring*
    • SPI and SENT interfaces allows use of multiple independent sensors for applications requiring redundancy*
  • Advanced diagnostics to support safety-critical applications, including:
    • On-chip, user-controlled logic built-in self-test (LBIST) and signal path diagnostics
    • 4-bit CRC on SPI messages
    • User-Programmable Missing Magnet Error flag for notifying controller of low magnetic field level
  • Diagnostics are initiated over the SPI or SENT interface and can directly test proper operation of the IC in safety-critical applications
  • EEPROM with Error Correction Control (ECC) configuration, sensor calibration including end-of line adjustments like programmable angle reference (0°) position and rotation direction (CW or CCW)
  • Available in both single-die and dual-die configurations
    • Dual-die devices contain two independent die housed within a single package
  • Absolute maximum VCC of 26.5 V for increased robustness and direct connection to automotive vehicle battery
  • Allegro Sensor Bias LDO

* See Selection Guide for more details.

The A1338 is available in single-die 14-pin TSSOP and a dual-die 24-pin TSSOP. Both packages are lead (Pb) free with 100% matte-tin leadframe plating.

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ASEK-20 Sensor Evaluation Kit
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A1337 Hardware (User Guide)