STMicroelectronics Rolls Out NFC Chip for Digital Car-key Systems
A new chip from STMicroelectronics is positioned as the first NFC Forum certified IC designed for use in automotive digital-key applications.
STMicroelectronics (ST) recently announced the ST25R3920B, a chip the company claims is the first NFC Forum certified IC for Car Connectivity Consortium (CCC) Digital Key applications. With the increasing amount of connectivity in our daily lives, ST’s contribution to enhancing our interactions with vehicles brings welcome advances for automotive designers looking to add the latest features to their projects.
In this article, we give a brief overview of the CCC, followed by an analysis of ST’s newly announced IC and its place in an automotive NFC ecosystem.
The CCC’s Digital Key Project
Acting as the unifying force to bring about smartphone-to-car connectivity, the CCC consists of a diverse group of engineers and manufacturers hoping to enhance the interaction between phone and vehicle.
Vehicles using the CCC Digital Key standard may be locked/unlocked, started, or have access shared all by using a smart device. Image used courtesy of the Car Connectivity Consortium
The leading CCC project, the Digital Key, hopes to act as an open standard by which smart devices may interact with and control vehicles. The Digital Key project leverages near-field communication (NFC) technology to allow secure communication between smart devices and vehicles. NFC is perhaps most well-known thanks to its use as a contactless payment method, but its use cases extend much further. In an automotive setting, NFC combined with the Digital Key project offers designers the ability to add another convenient method of entering, starting, or even sharing access to vehicles.
ST25R3920B: Certified for Digital Keys
Designed with car-door or center-console applications in mind, the ST25R3920B sports impressive specs for automotive engineers wanting to add additional phone connectivity to new vehicles. One of the most impressive new features is the upgraded active wave-shaping (AWS) system.
Using the built-in AWS, the received signal can actively prevent under/overshoot or reduce signal transients, helping to ease the certification process and allowing for easier interoperability between digital-keys and smartphones without requiring extensive antenna tuning during development.
An example of active wave shaping being used to shorten rise time. Compared to the original signal (yellow), the waveform using AWS (green) exhibits a considerably shorter rise time without experiencing considerable overshoot. Image used courtesy of STMicroelectronics
In addition to AWS, the ST25R3920B supports dynamic power output (DPO) in order to enable a long connection range and provide a consistent experience within this range. The chip’s 1.6 W power output helps maximize the interaction range while the integrated DPO ensures that systems built using this chip can protect target devices and meet certification limits.
Integrating Into the Broader NFC Ecosystem
The specifications of the ST25R3920B make it a suitable candidate for many CCC Digital Key applications. The new IC may be integrated within the door handle of a vehicle along with an antenna and microcontroller for keyless entry using NFC tags or smartphones since the high dynamic output power helps compensate for loss and small antenna size, which are major limiting factors for systems integrated in door handles.
Example CCC digital key solution leveraging ST devices embedded in the door and console of the vehicle alongside the CCC Digital Key standard. image used courtesy of STMicroelectronics
Once inside the vehicle, the ST25R3920B may also be used for Digital Key applications such as keyless start or starting the vehicle via smartphone. After integration of the ST chip within the vehicle’s center console, communication with a smart-card or smartphone could allow for full vehicle startup without requiring a physical key.
In addition, by coupling with a Qi wireless charger, the ST25R3920B can be used as a protection method for NFC-enabled cards, which may be destroyed after being subjected to the high power produced by Qi chargers. More information can be found in the ST25R3920B datasheet.
The Phone-Car Integration Trend
The new product from ST is a positive step toward the development and adoption of the CCC’s Digital Key standard. Future cars leveraging the ST25R3920B may no longer require a physical key to enter and start and may instead rely solely upon the NFC information stored in a smartphone.
The versatility of NFC not only allows a new, convenient vehicle-access solution, but opens the door for many other integrations between phone and car such as active safety measures to prevent distracted driving or real-time vehicle diagnostic reporting, all of which make the simple act of driving a more enjoyable experience.