NEUBIBERG, GERMANY AND CAMBRIDGE, ENGLANDTwo new developments are promising to help the automotive, industrial, and communications sectors develop more energy-efficient systems. German chipmaker Infineon Technologies, for example, unveiled its new wireless receivers. According to the company, these receivers provide good levels of sensitivity and a multiprotocol ability while simultaneously demonstrating low power. Meanwhile, in England, audio and connectivity specialist CSR has developed a single-mode, single-chip Bluetooth low-energy platform. The firm claims that this platform can provide everything required to create a Bluetooth low-energy product on a single chip.
The Infineon receivers form a family of three products that are designated the TDA5240, TDA5235, and TDA5225 (see figure). The devices provide multi-band support (315, 434, and 868 and 915 MHz) for global capability. They can be used in various automotive applications like remote-keyless-entry (RKE) systems, tire-pressure monitoring systems, remote start, control, and status and alarm functions.
The design of these receivers makes them capable of handling some functions that usually fall under the domain of microcontrollers. The TDA5240, TDA5235, and TDA5325 replace the firm's TDA5230/31 receiver products. In addition, two of the new devices have the digital data-processing capability that was a design feature of the TDA5230/31 receivers. Intermediate-frequency (IF) filter functions and level shifters are now an integral design feature, although external filters can be used if necessary.
Designers will be interested in the integrated low-noiseamplifier (LNA) concept. Depending on the application, this LNA can extend the system range or eliminate the need for an external LNA. The receiver family's high sensitivity (typically 119 dBm for FSK and 116 dBm for ASK) results from a reduced noise figure and noise bandwidth. The devices support data rates with several embedded encodings and modulation schemes to 112 kchips/s (FSK).
In addition, design flexibility is enhanced by the receiver's multi-protocol handling. The receivers can handle data from RKE and TPMS transmitterseven with different modulation, bit rates, and data formats. The devices also feature low power consumption, which is partly attributed to the use of a CMOS process to create the receivers. The supply current is 0.8 A in power-down and 12 mA in run modes. A fast-reacting sleep function helps to cut power consumption. Interestingly, the host controller remains asleep when unwanted RF signals are received.