What does APIX stand for?

APIX stands for Automotive PIXel Link and is a multi-channel SerDes (Serializer/De-serializer) technology developed for high-resolution, compression-free video applications in motor vehicles.

Who are the chip manufacturers?

APIX was developed by Inova Semiconductors whose headquarters are based in Munich (Germany). Inova procures its own chips and licenses the intellectual property rights to other semiconductor suppliers. Inova does not have its own microchip production facility but is one of the largest suppliers of automotive SerDes products. Socionext, founded by Fujitsu and Panasonic, was the first manufacturer to adopt the technology and today, is the biggest licensee of APIX, followed by manufacturers such as Toshiba, Analog Devices or Cypress.

What are the applications?

Typical applications of APIX3 components are infotainment and entertainment systems, combi instruments and head-up displays in vehicles. The APIX3 generation can create multiple display connections with a bandwidth of up to 12 GBit/s, and supports HD and Ultra HD displays. APIX not only connects TFT displays with graphic units but can also create links between camera sensors of driver assistance systems and a central processing unit or directly with a display.

How was APIX introduced into cars?

Inova was the first company to focus on SerDes products. The APIX SOP was integrated into the head-up display of the BMW 7 series in 2008. The data rate was designed for 1 Gbit/s. The company originated from a start-up, which developed the GigaSTaR (Gigabit/s Serial Transmitter and Receiver) for passenger information systems emerging from 2000 onwards. Together with the Fraunhofer Institute for Integrated Circuits IIS, Inova completed the first fully functional chips in 2006. The introduction of APIX2 took place later in 2012, also at BMW, with up to 3 Gbit/s. The HSD cables used had a blue sheath to prevent confusion. The chips, on the other hand, are backwards-compatible. With APIX3, which was introduced at BMW in 2020, the use of coax cables was also possible. However, the maximum data rate of 12 Gbit/s could only be achieved with a shielded STQ cable or two separate coax cables. APIX3 enables infotainment architectures with 8K resolution and 10-bit RGB color depth. The transmitter devices also enable video transmission via the VESA DisplayPort interface. The industry standard VESA DisplayPort differs to other video interfaces above all in its high data rate, the support of all popular video formats up to and including 8K resolution, and the possibility of transmitting several independent videos simultaneously. The DisplayPort interface is practically a de facto standard for powerful SoCs, such as those used in vehicles today.

Is LVDS used?

Since the first APIX generation in 2008, Inova Semiconductors has consistently used the “Non-Return-to-Zero (NRZ)” line code and “Current Mode Logic (CML)” with differential transmission. This method, which has been tried and tested in RF technology, is characterized by low emissions and, at the same time, a high robustness against radiation. Transmission takes place in the APIX system with a constant serial bit rate that is independent of the pixel rate of the videos to be transmitted. Therefore, in terms of radiation and interference immunity, the entire system can be optimized for this frequency. Even when transmitting different video formats, the EMC behavior remains almost unchanged.

Is it possible to compensate for cable influences?

As an extremely important feature, for the first time, APIX3 has a fully automatic self and system calibration that covers all internal clock systems, as well as dynamically optimizing the sample points. In addition, the line driver stages and filters are adjusted after each reset so that the frequency response of various cable types and lengths is compensated and these can be used via “plug and play”. In addition, extensive diagnostic and compensation options are available to compensate for manufacturing tolerances, cable aging and temperature effects.

Christian Neulinger

Christian Neulinger is "Manager Radio Frequency & Simulation" and has more than 10 years of professional experience in the development and qualification of innovative electrical components for wired high-speed data transmission. As an active member of various standardization committees such as IEEE 802.3, he is involved in the development of new high-performance data transmission systems for the automotive industry.