Car radio; remote tuner platform supports worldwide radio standards

January 09, 2017 // By Graham Prophet
Maxim Integrated’s MAX2175 ‘RF to Bits’ tuner-based solution reduces cables and simplifies vehicle head unit design; designers can eliminate the need to rework a vehicle’s hardware to support worldwide radio standards, allowing updates by simply changing the vehicle’s software.

Traditional radio architecture, Maxim notes, brings many challenges to vehicle designers. The vehicle’s complex head unit must accommodate multiple tuners, manage heat dissipation, and receive multiple cables from the antennas. In addition, the received analogue signals pick up noise as they travel from the antenna to the head unit of the vehicle. Finally, baseband processing uses single purpose hardware, requiring separate designs to support multiple worldwide radio standards.


The RF to Bits tuners are now located in a quieter environment close to the antenna to minimize noise. Digital outputs of the tuners are serialized using Maxim’s gigabit multimedia serial link (GMSL) serializer and deserializer (SerDes) onto a single low-cost coax cable. Power for the remote tuner solution is also delivered on this single cable. Not only does this improve radio performance, but it also reduces the weight of the vehicle to provide better mileage. Removing all tuners from the head unit saves space and reduces both system complexity and heat dissipation in the head unit. In a 4-channel radio, for example, 4W of power can be removed from the head unit. In addition, the MAX2175 allows the baseband processing to be done in software on an automotive System-on-Chip (SoC), such as the Renesas Electronics R-Car H3 SoC. This software defined radio (SDR) approach enables flexible implementations by eliminating the need for a dedicated baseband processor. By simply changing the software, now any worldwide radio standard can be supported using the MAX2175.


Rather than having to redesign the head unit, designers can now optimize a single remote radio tuner architecture that scales to different use cases by managing the number of remote tuners; change software to support any worldwide radio standard. Replacing multiple tuners with a deserializer connected to the SoC reduces system complexity, space, and heat dissipation in the head unit; the IC comes in a 48-pin 7 x 7 mm TQFN package (-40 to +85C temperature range).