Data acquisition has always been a very essential element in mission-critical environments and applications. A battery-buffered SRAM (static random access memory) was therefore usually used to store data. Even though it ensures a high level of safety and security, SRAM has various drawbacks:
- Several components are needed (battery, power management controller) which take up a lot of PCB space and have a high failure rate.
- To prevent the battery from overheating, it is usually assembled after the reflow process, which ultimately results in higher production costs.
- Industrial robots and vehicles are often subject to vibration, resulting in connectors that hold batteries in place becoming loose or detached. This reduces the reliability of the entire system.
- The batteries also need to be maintained and replaced during the long operating life of a typical industrial robot or vehicle.
- Moreover, the batteries fail to comply with RoHS directives and often create issues for operators when it comes to disposal.
For these reasons, non-volatile memory (NVM) is increasingly being used in industrial applications. EEPROMs are often the first choice. They are, however, usually unsuitable as most applications require real-time reliability for data acquisition. Further, EEPROMs are not particularly energy-efficient. However, low power is a critical factor since data must be continuously collected in these applications.
Main memory requirements
Due to the requirements of continuous data acquisition and the demand for a long service life, memories for industrial and automotive applications, but also for medical applications, must offer practically unlimited endurance.
F-RAM (ferroelectric random access memory) has a higher endurance than EEPROM and – in contrast to EEPROM – stores data immediately (see table). It is energy-efficient, and does not require an additional battery to have enough energy for storage in the SRAM. Moreover, a memory controller is not necessary, which saves both space and money. The reduced number of components also enhances reliability. Yet another advantage is the large variety of products available on the market, ensuring availability of the ideal F-RAM solution for every application.
Data acquisition trends
Trends shaping data acquisition in corresponding applications can currently be observed in industry, as well as in the medical and automotive markets.
Trend in the industrial sector: Designers of industrial applications need to look at whether data acquisition should occur centrally in the main microcontroller or separately at each motor. At present, data acquisition applications require up to 1 MB of memory at the motor. With controllers, on the other hand, up to 16 MB are required.
For high-speed applications, such as six-axis robot controllers, Infineon’s latest NVM generation, F-RAM Excelon, offers high memory density and a quad SPI (QSPI) for fast data throughput. For applications with lower requirements, for example a motion control application with three motor controllers, lower density models with a serial peripheral interface (SPI) are also available from the series.
Trend in the automotive sector: Automotive systems require continuous data recording and must acquire sensor data without delay if power fails. In harsh operating environments with extensive requirements on the number of read/write cycles and data retention, the most stable performance possible is necessary, which also supports efficient interfaces with a low pin count and high speed. The F-RAMs of the Excelon Auto series have been designed specifically for this purpose: They acquire data immediately without any holding time and the need for additional components. They support a QSPI with up to 108 MHz and are AEC-Q100-1, -2, and -3 qualified. The storage components thus meet the criteria for functional safety and security. With 100 trillion write cycles, an Excelon car can write data for 20 years.
Trend in the medical sector: Increasing connectivity and the Internet of Things with wearables and remote patient monitoring systems are enabling care that is gradually transitioning from hospital to home. Drivers of this development are a rapidly aging population and rising health care costs, especially in industrialized nations.
Mobile medical devices for the home, such as infusion pumps or pacemakers, enable remote therapies. However, this requires significantly more extensive and reliable real-time data acquisition to ensure efficient and secure operation, also in the event of possible power failure. Low power plays a key role in this respect to maximize the battery life of devices.
Thanks to delay-free write functions, virtually unlimited service life, and ultra-low power modes, the Excelon F-RAM devices meet all the requirements (Fig. 1). Equipped with the latest GQFN package, they also offer a small form factor – an advantage especially for wearables. In addition, Infineon’s F-RAM cells are robust enough to withstand magnetic field intensity and radiation. They thus reduce risks from external systems and prevent further intervention to replace storage components.
Summary
The examples show that the demand for reliable, fast, low-power, and high-performance F-RAMs has increased significantly across a wide range of applications that rely on data from multiple sensors. This is especially true in mission-critical areas, where data loss can significantly compromise safety and security mechanisms.
Furthermore, data acquisition plays a key role as an enabler of new AI and ML capabilities, such as predictive maintenance. It provides the data that help to promote innovation in these applications.
Their virtually unlimited service life combined with instant and reliable data acquisition and high data throughput make Infineon’s F-RAMs first choice for high-performance data acquisition in ADAS, industrial robots, and medical devices. Thanks to their varying densities, F-RAMs meet the requirements of various applications. This also gives developers the flexibility to meet the yet-to-emerge requirements of next-generation edge technologies.
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