Embedded Non-Volatile Memory IP for Automotive Markets
Kilopass offers state of the art antifuse OTP memories fully compliant to Automotive standards.
The first Kilopass product carried through the required flows and processes to achieve compliancy to Automotive standards, was the 128Kb XPM IP (Intellectual Property) in TSMC 16FFC technology node. Other products are in the pipeline and some are from larger geometries, including 28nm, 40nm and 55nm.
But, what does it mean for an OTP (one-time programmable) product to be compliant to Automotive standards? It means that it must be designed, developed and qualified following three standards which target zero defects and zero failures along the life of the product, which may span 15 to 20 years.
The three standards are:
1. Total Quality Management as per ISO/TS 16949
From the abstract: “defines the quality management system requirements for the design and development, production and, when relevant, installation and service of automotive-related products”. It requires developers/suppliers to comply to organizational processes and procedures that assure measurable and auditable quality levels of the development flow as well as the final product.
2. Functional Safety requirements as per ASIL (Automotive Safety Integrity Level) defined in ISO 26262
Safety requirements are intended to avoid risks and prevent harm to vehicle occupants as well as to the external world. Safety levels are determined for “functions” (such as airbag control, braking system and vicinity sensors); An OTP is part of an ECU (Electronic Control Unit) that controls one or some function. ASIL has four levels of compliance: A, B, C, D, the latter being the highest level of safety. ISO 26262 provides guidance to determine the proper safety level of functions.
3. Product Reliability as per the Automotive Electronic Council AEC-Q100
AEC defines a set of stress tests (HTOL, ELFR and EDR, for example) for the qualification of ICs designed for the harsh automotive environment. These stress conditions have the objective to accelerate the detection of possible failures in a short time linearly equivalent to the expected operational lifetime of the IC in such an environment. IC reliability along the expected life span of the product is maximized through successful qualification in conjunction with statistical analysis and design for test, aiming for “Zero Defects”.
For Kilopass it was straightforward to render its OTP products Automotive compliant, especially for Grade-1 operating conditions (Grade-0 requires a bit more work).
This results from the fact that most of the recommended structures and required processes for achieving zero defects were and are already implemented in all Kilopass products. These include, but not limited to:
- Smaller capacity OTP arrays are 100 percent redundant.
- Large capacities are equipped with ECC SEC/DED (Single Error Correct/Double Error Detect)
- Self-Test capabilities are built into the OTP IP BIST (Built-In Self-Test)
- Self-Repair structures are available within the OTP IP BISR (Built-In Self-Repair)
- Total verification of defects at the bitcell level by applying stress voltage.
- Qualification is performed through HTOL (High-Temperature Operating Life) at +125C (Grade-1)
- HTDR (High Temperature Data Retention) is replaced with HTSL (High-Temperature Storage Life), as described in AEC_Q100-005
- Characterization is performed at -40C and +125C, for both READ and PROGRAM
The concept and requirement of zero defect is clearly a welcome must for modern vehicles as it’s aimed to assure safety.
Driving a modern car or truck today is like driving a complex computer system which has the scope to transport people and freight from a geographic point to another through the road infrastructure and, to do so, it just happens it has engine and wheels.
The function of automotive vehicles remains the same, but innovative technology is dramatically improving every component of the whole, while adding new safety capability. Electronics in the form of ADAS (Advanced Driver Assistance Systems) is certainly among the most innovative element in safety.
The backbone of electronics in modern cars is the CAN-bus (Controller Area Network) that connects the many Electronic Control Units (composed of MCU, memory and interfaces) that direct functional operations of the vehicle. Data are exchanged among the ECUs through the CAN-bus.
After the experimental and successful hacking events of the last few years (that accessed unsecured ECUs connected to the cellular network and took full control of the vehicle from a remote computer), secure access to the ECUs is increasingly becoming a major focus of developers and standard bodies.
How can the access to the ECUs and to the CAN-bus be made secure?
Securing the CAN-bus requires data encryption. Here memories may not have a role.
To secure access to ECUs instead, Kilopass OTP are a perfect solution once the concept of “root of trust” will become standard for ECUs.
At that point, the security keys (almost certainly Public Keys) that the “root of trust” requires for verifying updates/changes to the MCU software, can be stored in the Kilopass OTP which is architected to be inherently secure to hacks and attacks. Moreover, the keys can be changed any time if the OTP capacity is chosen to allow updates of its content.
Kilopass OTP provides the highest level of resistance from side-channel as well as physical attacks. It is the storage mechanism used today in millions of set-top boxes for securing the keys to broadcast content.
Beyond security keys, Kilopass OTP are a perfect fit to store configuration parameters and settings for the ECU and the sensors it controls. Also the MCU software can be stored in Kilopass OTP (capacity of one instance is max 1Mbit and multiple instances can be integrated in the ECU).
Finally, besides security, here are some other real advantages of Kilopass OTP
- Much Lower cost compared to other NVM
- Simple CMOS process, using regular core MOS devices and no additional process masks
- Easy scalability toward lower technology nodes: 10nm OTP is in pre-production now.
- Guaranteed data retention and insusceptibility to radiation. It is just a broken gate oxide after all.
Cost control together with reliability, safety and security requirements are making the case of OTP in the Automotive ECUs market. Kilopass, thanks to its state of the art technology, witnesses this trend with increasing booking numbers in the Automotive space quarter after quarter.
|Market||OTP usage||End Product||Kilopass Advantage|
|Automotive||Calibration, trimming, code storage, security keys||Control systems, DSPs, in-car communications, and infotainment systems||
OTP NVM Automotive Applications