Ferroelectric RAM remembers in-car entertainment

Daesung-Eltec of Korea has used FRAM in the design of its new digital signal processing based car audio platform.

Daesung-Eltec selected the FM24C64 - a 64Kbit FRAM with two-wire serial interface - to enable sophisticated memory functions such as storing audio, channel and favourite artist/song settings, as well as the resume play and the favourite artist/song alert features.

FRAM's nonvolatility, no delay writes, virtually limitless endurance, small footprint and cost effectiveness make it the ideal memory technology for advanced digital automotive audio systems.

Daesung-Eltec, a leader in car audio/video and digital multimedia systems, designed the DSP-based audio platform for use in Renault Samsung Motors vehicles.

The company selected FRAM due to its write speed, which is fast enough to reduce backup time and, therefore, eliminate the need for an onboard capacitor to manage power down events.

This is bolstered by FRAM's high endurance, which enables the system to write data in real time without any fear of wearing out the memory.

Digital radio has transformed the car radio from a simple audio processor to a sophisticated infotainment system, with enhanced CD-like audio quality, superior signal reception, and pioneering memory functions.

In such systems, the FM24C64 is integral for saving DSP filter configurations and settings so that users can recall from a selection of preferred audio settings.

Ramtron's FRAM also stores favourite radio stations and artist and song names so that users can program the receiver to send an alert when a favourite song/artist is played on any radio channel.

Advanced car audio platforms download and store information in nonvolatile memory.

The uncertainty of the frequency of changes in this information makes it risky to use a nonvolatile memory with limited endurance, such as EEPROM.

A common workaround is to maintain the downloaded information in RAM and write it to the EEPROM when power is turned off.

This method requires a large capacitor to maintain power while the system writes data to the EEPROM.

While inexpensive, capacitors are physically bulky and undesirable in ever-shrinking electronic radios.

FRAM is a simpler solution that can be written to an unlimited number of times and can store information instantly on power down without a complicated work around.

Daesung-Eltec designed the 64Kbit FRAM into its automotive audio system to save system board space and time to market as well to guarantee data integrity.

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