A family of MEMS-based motion sensing accelerometers combining low power, operational precision, and ultra-low noise suitable for portable electronic devices

According to market research firm iSuppli Corp, the global MEMS market is expected to grow by 11% in 2010, driven by strong sales of mobile phones, game controllers, and digital cameras. Most of these devices are equipped with motion-sensing features capable of image stabilization (IS), tap control, anti-theft, and orientation detection. Furthermore, as market demand for next-generation applications such as intuitive user interfaces and location-based services continues to rise, improvements in precision and battery life are essential.

In response to these demands, Freescale Semiconductor today announced an advanced family of 3-axis accelerometers designed for smart mobile devices that offers enhanced battery life while delivering industry-leading resolution, low noise, and performance suitable for embedded devices. The MMA845xQ family enables system designers to easily integrate advanced real-time applications, such as pedometers and games, as well as standard functions like orientation sensing, into their products. Furthermore, the latest Freescale accelerometers extend the battery life of smart mobile devices such as smartphones, navigation systems, MP3 players, e-readers, and netbooks.

"In addition to the recently announced Xtrinsic sensor family, Freescale has designed the MMA845xQ family, which offers outstanding motion, shock, tilt, and vibration sensing capabilities along with remarkably active power efficiency," said Demetre Kondylis, Senior Vice President and General Manager of Freescale's Sensors and Actuators business unit. "Freescale customers can now have a comprehensive motion sensing portfolio that is not only pin-compatible but also provides them with an ideal combination of performance, portability, and battery life."

The MMA845xQ accelerometer family, part of Freescale's Xtrinsic sensor solution line, is a new dimension of intelligent sensor utilizing embedded algorithms and computations across three advanced accelerometers. Together with a host processor, the embedded accelerometers assist in decision-making regarding contextual environmental sensing and support the ability to record high-precision motion for a wide range of consumer electronics devices, from smartphones and tablets to e-readers and remote controls.

This accelerometer is ideal for battery applications with low current consumption of 1.8 microamperes (μA) in standby mode and as low as 6μA in operating mode. This Freescale product features four power modes ranging from high resolution to low power, providing both best-in-class supply current savings and ultra-high resolution capable of detecting even very fine movements.

The MMA845xQ accelerometer includes a wide range of real-time functions such as directional shaking and orientation detection, tapping, impact, and drop detection. This device is a highly versatile product that supports basic applications requiring basic gestures such as lasso and flick, intermediate applications such as position and 3D gesture detection, and advanced applications such as dead reckoning or precise tilt detection.

Freescale has expanded the MMA845xQ family by announcing the 14-bit MMA8451Q and 12-bit MMA8452Q products today, in addition to the previously announced MMA8450Q. These devices feature compatible pin layouts, including register map arrangements between the accelerometers, maximizing hardware and software reusability between 12-bit and 14-bit designs, minimizing migration costs, and shortening time-to-market. The MMA845xQ accelerometers provide wide bandwidth and user-configurable sample rates ranging from 1.5 to 800 Hz to support a variety of applications, and operate within an I/O interface voltage range of 1.62V to 3.6V.

The MMA8451Q accelerometer integrates an on-chip FIFO (first-in/first-out) memory buffer capable of storing up to 32 sets of X, Y, and Z data samples. This reduces the functional load on the host processor, thereby improving overall system power efficiency and response times. Using the FIFO buffer in conjunction with other embedded functions allows the host processor to analyze only the necessary data while preventing potential data loss when multiplexing other sensors on the same IIC bus. The combination of the host processor and the FIFO function enables current consumption reductions ranging from 78% to over 96%, depending on the microcontroller's state and the selected output data rate.

Feature Summary
• 14-bit and 12-bit digital output
• Resolution: (14-bit) - 0.25 mg. (12-bit) - 1mg
• Low noise: 99 microg per root-Hz (independent of resolution)
• Low power mode: 6 μA
• I/O interface supply voltage: 1.62 ~ 3.6V
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