LPDDR5: One of the key technologies for realizing intelligent driving

In 2020, both SK Hynix and Micron have released test samples of DDR5, which makes people really look forward to the commercial prospects of DDR5. For example, SK Haili’s DDR5 memory provides at least twice the bandwidth of DDR4 memory in terms of parameters. The memory frequency will jump from 3200MHz up to 8400MHz. From DDR3 to DDR4, the bandwidth has increased by 33% (from 1600 MHz to 2133 MHz). With DDR5, SK hynix aims to increase the bandwidth per DIMM by more than 50%.

In 2020, both SK Hynix and Micron have released test samples of DDR5, which makes people really look forward to the commercial prospects of DDR5. For example, SK Haili’s DDR5 memory provides at least twice the bandwidth of DDR4 memory in terms of parameters. The memory frequency will jump from 3200MHz up to 8400MHz. From DDR3 to DDR4, the bandwidth has increased by 33% (from 1600 MHz to 2133 MHz). With DDR5, SK hynix aims to increase the bandwidth per DIMM by more than 50%.

LPDDR5: One of the key technologies for realizing intelligent driving

While DDR5 is popular for its increased memory, processing reliability and performance, one feature that is often overlooked is its security features – especially in automotive applications.

Recently, Tesla announced a recall of some Model X and S models due to a problem with the 8GB embedded multimedia card (eMMC) in its microcontroller. The accumulated wear and tear on the eMMC can damage the main Display, vehicle warning signals, storage devices and inspection cameras. All these losses add up to exhaust the reliability of memory safe operations.

This recent incident shows that security is an important part of a car’s data processing system and memory.

DDR5 is a storage technology that focuses on device-level security. DDR5 uses dynamic random access memory (DRAM) to provide devices with faster data rates, greater bandwidth, and enhanced performance. Typically, we only hear rumors of DDR5 being used in mobile devices and CPUs, but DDR5 is capable enough to operate in automotive applications as well.

LPDDR5: One of the key technologies for realizing intelligent driving

Introducing DDR5 to automotive systems improves memory, processing, reliability and performance while improving safety capabilities. More recently, Micron highlighted this point with “the industry’s first low-power DDR5 DRAM (LPDDR5) memory that meets the automotive safety standard with a key hardware focus.”

DRAM Levels: Standard, Graphics and Automotive

Before delving into the intersection between automotive memory and hardware security, let’s first outline the three levels of DRAM:

Standard DDR: Supports wider channel widths, higher densities and different form factors for server, cloud computing, networking, notebook, desktop and consumer applications. DDR4 is currently the most commonly used standard in this category, supporting data rates up to 3200 Mbps. But once up to DDR5, bandwidth speeds are expected to hit 6400 Mbps.

Graphics DDR: It targets data-intensive applications that require very high throughput, such as graphics-related applications and data center acceleration. Switching to any graphics-based DDR5 enables full HD video files at 3.7 GB/s.

Low Power Mobile DDR (LPDDR): Ideal for area and power sensitive mobile and automotive applications. LPDDR offers narrower channel widths and several low-power operating states. LPDDR4 and LPDDR4X support data rates up to 4267 Mbps and are common standards in this category.

LPDDR5: One of the key technologies for realizing intelligent driving

LPDDR5: One of the key technologies for realizing intelligent driving

Error correction code ECC cannot be ignored

An important consideration for secure automotive memory is error correcting code (ECC). Briefly talk about what is ECC. ECC is memory error correction. In short, it has the function of finding and correcting errors. It is generally used in high-end desktop computers/servers and graphics workstations, which will make the entire computer system more secure and stable at work.

This is a key automotive protocol for automotive memory, capable of self-detecting and retrieving data errors transmitted through embedded hardware. SK hynix said ECC is a key factor in automotive memory as it prevents system failures while providing a smooth autonomous driving experience.

LPDDR4 is capable of transferring data arrays of 128 bits, of which 8 bits are used for ECC retrieval. By comparison, LPDDR5 is expected to have a 16GB DRAM to support a data transfer rate of 5.2GB/S, which would be nearly 60% faster than its predecessor.

LPDDR5: One of the key technologies for realizing intelligent driving

While this level of security and speed is a great feature of memory devices, designers should consider other design features of DDR5. For example, DDR5 has a lower operating voltage VDD, which means less margin for noise immunity. In addition to this, designers will have greater flexibility in complex automotive designs due to the presence of independent power management in DDR5 embedded ICs.

Micron’s new LPDDR5 and ASIL classifications

Micron recently released new LPDDR5 memory designed to improve automotive safety. Micron’s LPDDR5 comes with extensive functional safety evidence and further risk reduction by system integrators, ADAS, in-vehicle infotainment, digital cockpit and machine learning in system architectures. In addition, Micron simplifies system design and accelerates time-to-market for automotive customers. The device complies with Automotive Safety Integrity Level ASIL D.

LPDDR5: One of the key technologies for realizing intelligent driving

Speaking of ASIL, it is a risk classification defined by ISO 26262 (International Safety Standard for Electrical components of Automotive Systems). Compliance with ISO 26262 requires vehicles to maintain the highest standards of safety features in the game, which is increasingly important for ADAS.

ASIL divides security levels into:

ASIL B: Brake Lights, Rear View Camera, Headlights
ASIL C: Active suspension, radar cruise control
ASIL D: Anti-lock Braking, Electric Power Steering, Airbags, Engine Management

LPDDR5: One of the key technologies for realizing intelligent driving

Safer LPDDR5 addresses system and hardware failures

To meet the highest level of security requirements, LPDDR5 typically includes security mechanisms to detect and control memory errors during operation.

Micron divides the security risks of automotive memory into two categories: system failure and hardware failure. System failures are handled by the memory’s ECC, which detects errors that are classified during data transfer. Hardware failures must be resolved during the testing and manufacturing phases.

Summarize

Memory is an essential component of any Electronic system used in applications such as mobile devices, IoT, automotive, and cloud data centers. SoC designers must choose the right memory technology to provide the necessary performance, capacity, power and area. DDR has become a real memory technology and is available in several categories, including standard DDR and low-power DDR (LPDDR). The latest standard LPDDR5 and DDR5 offer higher performance at lower power consumption. LPDDR5 operates at speeds up to 6400 Mbps and has many low-power and RAS features, including a novel clocking architecture that simplifies timing closure.

LPDDR5: One of the key technologies for realizing intelligent driving

DDR5 DRAM with data rates up to 6400 Mbps supports higher densities, including dual-channel DIMM topologies for improved channel efficiency and performance. In the highly monopolized DRAM market, Samsung, Micron, and SK Hynix compete with each other in the LPDDR5 field. Among them, Samsung announced the successful development of the industry’s first 10nm-class 8Gb LPDDR5 DRAM in the first half of 2019, and then successively launched 12Gb and 16Gb LPDDR5; SK Hynix has also exhibited LPDDR5 products. But car-grade DRAM is just emerging, and for autonomous driving, safety is a top priority for all vehicles, especially those equipped with autonomous systems. As DDR5 enters the automotive market, a variety of sensors, controllers, switches, and doors will flourish as they simultaneously operate and transmit data at faster and safer speeds than ever before.

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