Asahi Kasei Microsystems AK8975
3-axis Electronic Compass
1. Si-monolithic 3-axis geomagnetic sensor LSI 2. Measurement range - ± 1200 microT 3. Functions - Time-sharing sequencer controls automatic measurement of 3-axis magnetism - Built-in ADC for magnetometer data output - 13-bit digital output (resolution: 0.3 microT) - Individual adjustment data, already stored before shipment at AKM, such as sensitivity of sensor - Serial interfaces (separated from main power supply, low voltage is acceptable) · I2C-bus interface (can be operated at Standard- or Fast-mode) · 4-wire SPI - Operation modes: Power-down, Single measurement and ROM access - Magnetic sensor overflow monitor function - Power on reset circuit - Interrupt function for measurement data ready - No clock input required (built-in oscillator) - Automatic power-down function 4. Operating temperature range: -30°C to +85°C 5. Operating supply voltage range: Vdd = +2.4V to +3.6V, Vid = +1.65V to Vdd 6. Current consumption - 3-axis magnetism measurement (ave.): 350 microA (typ.) at 8 Hz repetition rate - Power-down: 3 microA (typ.) 7. Packages - AK8975: 16-pin QFN (4.0 4.0 0.75 mm) - AK8975B: 14-pin WL-CSP, BGA (2.0 2.0 0.6 mm)
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 ± 1200 microT is provieded. 4. Such high resolution as 0.3 microT is realized with low average current consumption; 350 microA at 8 Hz repetition rate. 5. The serial interface corresponds to I2C-bus interface and 4-wire SPI, so X-, Y-, and Z-axes components of geomagnetism can be output as digital signal. 6. A dedicated power supply is used for the serial interface, so the low-voltage operation at down to 1.65V is also covered. 7. A memory for storing the individual adjustment values of sensor sensitivity is built-in. The adjustment values are stored before shipment at AKM factory. 8. By the DRDY pin and register, system is informed that measured data is written to the register after measurement and ready to be read. 9. Built-in oscillator dispenses with the external clock input.