Integrated RF IC for passive entry and low-power tracking systems

April 28, 2016 // By Graham Prophet
Melexis' multi-channel, programmable device, MLX73290-A, features a multi-channel RF transceiver, combined with a 3-dimensional low frequency (3DLF) interface that supports ultra-low power operation.

Through its integration of sub-GHz RF and low-frequency technologies, this RF IC is optimized for use in vehicle activation, logistics and Internet of Things (IoT) applications. These include passive keyless entry & start (PKES), secure access and low-power tracking systems, where a very-low power wake-up function together with long range, high speed RF feedback are mandated.

The 3DLF interface features an automatic and fully programmable scan mode, constantly polling for a valid low frequency (LF) signal on the three differential receive-coil inputs. This permits a typical 4 µA power consumption in LF detection mode. The LF-RSSI feature allows precise monitoring of the received LF field. Working in combination with the system’s host microcontroller, it can run in passive transponder mode and thereby support battery-less operation.

Optimized for use in the sub-GHz ISM bands, covering 300 MHz to 960 MHz, the integrated RF IC delivers a transmitter output of -20 dBm to +13 dBm. It has a receiver sensitivity down to -120 dBm in a 15 kHz channel bandwidth. A 250 kbps maximum data rate is supported. Modulation schemes that can be used are on-off keying (OOK), binary frequency shift keying (FSK), minimum shift keying (MSK), Gaussian minimum shift keying (GMSK) and Gaussian frequency shift keying (GFSK).