Reliable automotive data storage using F-RAM and NOR flash

By K. Josef, Infineon Technologies

As regulations around automotive data logging become more stringent, memory solutions must evolve to keep up. Event data recorders (EDRs) and data storage systems for Autonomous Driving (DSSADs) are facing increased legislative scrutiny globally—from the United States National Highway Traffic Safety Administration (NHTSA) to the United Nations Economic Commission for Europe (UNECE). These systems require storage solutions that combine speed, endurance, and power-loss protection.

Comparison between EDR and DSSAD data loggers

Comparison between EDR and DSSAD data loggers

Table 1: Comparison between Event Data Recording (EDR) and Data Storage System for Automated Driving (DSSAD) data loggers.
Comparison between EDR and DSSAD data loggers

Table 1: Comparison between Event Data Recording (EDR) and Data Storage System for Automated Driving (DSSAD) data loggers.
Comparison between EDR and DSSAD data loggers

Table 1: Comparison between Event Data Recording (EDR) and Data Storage System for Automated Driving (DSSAD) data loggers.

Challenges in current data logging systems

 An EDR system relying on volatile RAM buffers paired with EEPROM or data flash for long-term storage contains a major flaw – data in the buffer can be completely erased during a crash.

NHTSA's updated requirements make this challenge even more critical. EDR systems are now required to capture 20 seconds of pre-crash data at 10 Hz, compared to the previous 5-second, 2 Hz requirement, with enforcement starting September 1, 2027. Similarly, DSSAD systems must continuously store all events over a defined period, often a few months or more, putting additional pressure on both front-end and back-end memory components.

The solution is clear: automotive data logging demands power-loss protection at the front-end and high-density storage at the back-end.

How F-RAM and NOR Flash address the problem

Combining Ferroelectric RAM (F-RAM) with NOR flash effectively meets these requirements.

F-RAM for the front-end acts as a ring buffer for incoming data. Unlike volatile SRAM, F-RAM retains data even when power is lost, eliminating crash-related data loss. Key advantages include:

  • Fast write speeds for high-frequency data logging
  • Endurance of up to 10¹⁴ write cycles—well beyond logging requirements over 20-years
  • Non-volatile storage without needing a backup battery

NOR flash for the back-end handles long-term data storage. Infineon's SEMPER™ NOR flash family provides the required density for EDR and DSSAD applications with features such as:

  • Storage capacities in the gigabit range
  • Small-granularity random access for efficient event retrieval
Figure 1: The block diagram shows front-end and back-end storage in a logging operation

Figure 1: The block diagram shows front-end and back-end storage in a logging operation
Figure 1: The block diagram shows front-end and back-end storage in a logging operation

Figure 1: The block diagram shows front-end and back-end storage in a logging operation
Figure 1: The block diagram shows front-end and back-end storage in a logging operation

Figure 1: The block diagram shows front-end and back-end storage in a logging operation

For comparison, a volatile RAM-based system could lose up to 20 seconds of pre-crash data plus  additional time during an erase cycle if power fails mid-operation. Using an F-RAM front-end eliminates this risk entirely. Meanwhile, for DSSAD, frequent event logs could result in storage requirements in the order of hundreds of megabits.  SEMPER™ NOR flash meets capacity demands while EXCELON™ F-RAM ensures endurance throughout a 20-year vehicle lifespan.

A compliant memory architecture for the automotive industry

For automotive engineers designing EDR and DSSAD systems, combining F-RAM and NOR flash provides a reliable solution to meet strict regulatory standards. This architecture addresses the power-loss vulnerability of volatile RAM, delivers adequate storage capacity, and ensures durability over a vehicle's lifespan.

As regulations tighten and autonomous systems generate more data, dependable non-volatile memory will be essential. Explore Infineon's EXCELON™ F-RAM and SEMPER™ NOR flash portfolio to find the right solution for your automotive data logging needs.