Asahi Kasei Microsystems AK8973N

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Asahi Kasei Microsystems AK8973N


AK8973 is a geomagnetism detection type electronic compass IC. The small package of AK8973 integrates magnetic sensors for detecting geomagnetism in the X-axis, Y-axis, and Z-axis, and arithmetic circuit for processing the signal from each sensor. AK8973 outputs four data in total as 8-bit digital values respectively: 3-axis magnetic sensor measured values and temperature sensor read value. By processing the magnetic sensor measured values with an external CPU, azimuth data can be obtained. By using AK8973 integrated into the system, a navigation system is achieved with reduced space in portable equipment such as PDA or mobile phone incorporating the GPS function.


  1. 3-axis geomagnetic measurement by one-chip LSI has become possible by Si-monolithic Hall elements and by unique technology for magnetic concentrator.
  2. The combination of high-level technology of analogue signal operation and original digital estimation technology has achieved geomagnetic detection by Hall elements that had been thought impossible in the past.
  3. By using excellent linearity and wide dynamic range of Hall elements, very wide measurement range such as ± 2000 microT is provieded.
  4. Due to the built-in DAC for compensating the offset magnetic field generated by such as speakers, the position restraint with parts which generate the offset magnetic field is reduced, and the degree of freedom about layout is expanded.
  5. Due to the built-in 8-bit ADC and serial interface, X-, Y-, and Z-axes components of geomagnetism can be output as digital signal.
  6. The serial interface corresponds to the I2C bus.
  7. A dedicated power supply is used for the serial interface, so the low-voltage operation at down to 1.7V is also covered.
  8. A memory for storing the individual adjustment values of sensor sensitivity is built-in. The adjustment values are stored before shipment at AKM factory.
  9. The built-in temperature sensor generates the digital A/D-converted data and then the data is output from serial interface as digital data.
  10. The major circuit blocks of AK8973N/B/S are activated by the measurement request command from the controller, and transit to the power-down mode automatically at the end of measurement. That characteristic realizes the low power consumption required for mobile phones.
  11. The interrupt function for posting the completion of sensor signal measurement to the external CPU is built-in.
  12. Built-in oscillator dispenses with the external clock input.

Datasheet: File:Ak89731.pdf