Kionix Calls New Accelerometers the “Industry’s First” to Include Built-in Noise FilteringDecember 16, 2019 by Gary Elinoff
The KX132-1211 and the KX134-1211 are tri-axis, 16-bit accelerometers with built-in noise filtering.
Both units feature advanced data path (ADP) technology, which takes care of the noise filtering and sensor signal processing that must otherwise be carried out by the MCU. Kionix states that this reduces both the MPU’s computational loads and its power requirements.
Built-in ADP reduces MCU load. Image from Kionix
Both accelerometers are offered in 2mm x 2mm x 0.9mm LGA 12-pin plastic packages. The devices also operate over an expanded -40°C to +105°C temperature range.
Machine faults often reveal themselves through excess vibration. The KX132-1211 or the KX134-1211 are designed to note these excess vibrations, which can help designers to discover flaws early on and conduct preventive maintenance to head off larger problems.
This property, along with is power-conserving Wake-Up and Back-to-Sleep detection, makes the two accelerometers useful in several applications, including machine health, wearables, automotive smart keys, and logistics.
Differences Between KX132-1211 and KX134-1211
The KX132-1211 supports a frequency band of 4.2kHz in the X and Y axes and 2.9kHz in the Z axis. It also offers gRanges of ±2g, ±4g, ±8g, and ±16g.
The device offers a Wake-Up and Back-to-Sleep detection that is configurable down to 3.9mg.
Functional diagram of KX132-1211. Image from Kionix
The KX134-1211 supports frequency bands of 8.2kHz, 8.5kHz, and 5.6kHz in X, Y, and Z axes, respectively. Users can choose gRanges of ±8g, ±16g, ±32g, and ±64g.
The device offers a Wake-Up and Back-to-Sleep detection that is configurable down to 15.6mg.
Both devices consume 0.67μA in low-power mode. A Wake-Up function reports when acceleration exceeds a preset limit. Conversely, there is also a Back-to-Sleep function that notifies the MCU when no acceleration has been detected over a period of time.
These functions can serve to switch both the accelerometer and the MPU to lower power modes when users don't need their active service. This might be an especially useful feature in applications, such as smartphones or wearables, where saving power is a vital design feature.
Advanced Data Path
Advanced data path (ADP), which offloads the filtering from the host MPU, is implemented by including multiple customizable frequency filters.
ADP filtering. Image from Kionix
In the example above, using a low-pass or high-pass filter provides for a signal pass-through. Because each filter can be turned on or off as needed, both low pass and high path can be used simultaneously, creating the band path illustrated on the bottom of the illustration.
Evaluation and Support Tools
The KX134-1211-EVB110 evaluation board. Image from Mouser Electronics
There is also an IoT evaluation and development kit, which supports an array of both Kionix and ROHM products. These include accelerometers, gyroscopes, and magnetometers from Kionix and a barometer from ROHM.
Around the Market
Accelerometers have wide applicability across a range of product classes. As such, it’s not surprising that Kionix has many competitors in this field.
The LIS2DS12 from STMicroelectronics is a three-axis accelerometer offering ±2g, ±4g, ±8g, and ±16g ranges. The unit can measure accelerations with output data rates from 1Hz to 6400Hz.
Analog Devices offers the ADXL344 with 13-bits of resolution up to ±16g. The three-axis device communicates using an I2C or an SPI (3- or 4-wire) digital interface.