Infineon wireless receivers offering high sensitivity, low power consumption and multi-protocol support

Infineon Technologies AG has introduced an enhanced family of three wireless control receivers offering highest available sensitivity and low power consumption. The TDA5240, TDA5235 and TDA5225 devices provide multi-band support (315MHz, 434MHz, 868MHz and 915MHz) for worldwide coverage and are suited for use in automotive applications including Remote Keyless Entry (RKE) systems, Tire Pressure Monitoring Systems (TPMS), remote start, control, status and alarm functions. The receivers also are capable of taking over some of the tasks that are typically performed by the system’s microcontroller.

The TDA5240, TDA5235 and TDA5325 are successors to the TDA5230/31 receiver family. Two of the devices include the powerful digital data processing introduced with the TDA5230/31, with overall performance and feature set enhancements. Functionalities like IF filter (optional usage of external filter is possible) and level shifters are now integrated. Only a few external components are needed, which leads to reduced BOM. An integrated Low Noise Amplifier (LNA) concept provides system developers with enhanced design alternatives. Depending on application needs, the LNA can extend the system range or eliminate the need for an external LNA to reduce system complexity and costs.

“The new devices combine highest sensitivity and low power consumption with multi-protocol handling to increase performance and reduce system cost,” said Matthias Halsband, Director Wireless Sense and Control within the Automotive division at Infineon Technologies.

High sensitivity

High sensitivity of the new family (typically -119dBm for FSK and typically -116dBm for ASK) is due to a reduced noise figure and noise bandwidth using improved digital signal processing. Compared to Infineon’s current receiver products, which offer an average data rate of 40kchip/s, the TDA5240/35/25 devices provide a data rate with several embedded encodings and modulation schemes specified at up to 112kchip/s (FSK).

The wireless control receivers are based on a CMOS process providing low power consumption. The supply current is only 0.8μA in power down and 12mA in run mode. An ultrafast fallback to sleep function reduces the receiver’s active time, when no data is available for further reduction of the average power consumption. Up to four parallel parameter sets for autonomous scanning and reception from different sources reduce significantly the host processor and system standby power consumption.

System designers can use the multi-band, multi-channel receivers for systems operating at frequency bands 315/434/868/915MHz, with one crystal for all supported frequency bands. A high-resolution sigma-delta fractional-N PLL synthesizer provides a fine multi-channel resolution of 10.5Hz.

Multi-protocol handling enables flexible designs based on one platform. The receivers are able to handle data from both RKE and TPMS transmitters, even when they have different modulation, bit rate, and data format. One device can be used for multiple applications (RKE, TPMS, remote start, etc.) where today there is need for two.

The TDA5240 and TDA5235 support an autonomous receive mode where desired payload is automatically extracted and interrupts can trigger the host controller to read payload from the FIFO memory. The host controller remains asleep when unwanted RF-signals are received. This reduces noise from the host controller, which further improves sensitivity and reduces power consumption of the system. Support for additional encodings (bi-phase, NRZ) and market-leading coverage of automotive RKE/PASE/TPMS protocols results in high flexibility while minimizing software development effort. The TDA5225 comes without digital baseband processing to support designs based on standard concepts with data processed in the microcontroller.

Availability and pricing

The product family members differentiate mainly in the multi-channel and digital baseband functionality. The new pin-compatible TDA5240/35/25 wireless control receivers in TSSOP-28 packages are available in volume production. The automotive qualified devices operate at a supply voltage of 3.3V or 5.0V and at the temperature range of -40 °C to 105 °C. Single unit price for 50k ordering quantities starts at Euro 0.80 (US $1.10) for the TDA5225. In addition, Infineon provides starter kits and tools to support the design-in of the new devices.

Further information on the TDA5240/35/25 wireless control receivers is available at www.infineon.com/wirelesscontrol and at www.infineon.com/TDA5240.