There is increasing demand for a sensing function to monitor an object’s status in remote locations as IoT products are expected to grow in the market.
Asahi Kasei Microdevices Corporation, (AKM), has developed the AK09970, a 3-axis magnetic sensor that is able to detect magnetic signals in X, Y, and, Z directions. The AK09970 supports wide measurement range with high resolution in 3-axis detection and captures magnetic fields in 3-dimensions. With these abilities, it is great device for controlling the direction of security cameras and connected home, (smart home, smart house), smart locks, along with door and window open/close detection.
Samples are available now, with mass-production of the AK099770 in summer 2017.
- High Sensitivity Setting / Wide Range Setting
The AK09970 has a high sensitivity setting of ±36 mT on 3-axes.
It is able to measure a wide range of magnetic field from microtesla to millitesla such as from geomagnetic to a magnet since it has high measurement resolution of 1.1 µT/LSB in high sensitivity mode.
In addition, wide range setting of 101 mT can be achieved via the Z axis.
- Low-power Consumption when Battery Life is Critical
The AK09970 can operate using only a few µA, thus consuming a very low current that satisfies a demand of IoT products. It contributes to a long battery life of a product that needs constant acquisition of sensor data to monitor an object’s status.
- Magnetic Field Output (Digital)/Data Ready Alert (DRDY bit)
The AK09970 measures magnetic field on all 3-axes via intermittent drive and outputs the result as digital data, (supporting I2C/SPI communications). It outputs a Data Ready Alert to the dedicated register when the measurement data is updated. (0.25/0.5/1/10/15/20/100 Hz interval modes or single measurement mode is selectable for intermittent drive options.)
- Magnetic Event Interrupt Function
The AK09970 has magnetic event interrupt pins. Two thresholds can be programmed for each axis, (setting the resolution equal to the measuring resolution). When a magnetic field that exceeds the threshold is sent, the AK09970 outputs a “Magnetic Event” interrupt to registers or external output pins. The magnetic event that causes an interrupt output that can be selected freely by setting a register. (Data Ready Alert mentioned in above can also be output from an interrupt pin). Two interrupt pins are available for magnetic event: the INT pin for push-pull output and the OD-INT pin for open-drain output. Therefore, the output format can be selected depending on the customer’s product.
Specification
| Range Setting | High sensitivity setting | Wide range setting |
| Magnetic sensitivity | 1.1µT/LSB | 3.1µT/LSB |
| Measurement range | X,Y,Z ±36mT | X,Y ±35mT, Z ±101mT |
| Power Setting | Low power drive | Low noise drive |
| Noise | 15.0 µTrms | 5.0 µTrms |
| Idd average | 0.6 µA@1 Hz 2.7 µA@10 Hz |
1.5 µA@1 Hz 11.9 µA@10 Hz |
| Output bit | 16-bit | |
| Output pin | Interrupt pin (CMOS/Open Drain) | |
| Interface | SPI/I2C | |
| Power supply | 1.7 to 3.6 V | |
| Package | 14-pin QFN (3.0×3.0×0.75 mm) | |
