The AX5043 is a true single chip narrow-band RF transceiver for the 70 MHz to 1050 MHz frequency bands. It offers the unique receiver combination of highest sensitivity, high selectivity and ultra-low power. Combined with its high transmit power capability (up to 20 dBm) a link budget of 143 dB is achieved. Only a few external components are required. The AX5043 works perfectly down to 1.2 kbps in a 6.25 kHz channel. Though a TCXO is recommended for such operation, the AX5043 can also be operated with a normal XTAL if the necessary precautions are taken into account. An integrated voltage regulation system allows the direct use of batteries and short start-up times enable time- and energy-efficient protocols. this makes the AX5043 ideal for battery powered portable applications. AX5043 features a lowerst power wake-up clock and timer, which typically consume 500 nA, allowing it to autonomously handle wake-on-radio cycling.The AX5043 supports FSK, MSK, 4-FSK, GFSK, GMSK and ASK modulations. In transmit mode all modulations are shaped to meet the most stringent regulatory requirements. Power ramping can be configured without restrictions. Maximum output power levels are 16 dBm at 868 MHz and 20 dBm at 70 MHz carrier frequency. The configurable packet engine supports a wide range of packet formats that are handled without microcontroller intervention.AX5043 is supported by the AXSEM development kit DVK-2. This is a complete and flexible ready-to-go solution for easy testing, evaluation and development of AXSEM RF ICs. It is suited for real performance tests as for application code development. The DVK-2 is based on the AX8052F100 MCU and AXSEM offers both the AX-RadioLab GUI as well as the advanced graphic integrated development environment AX8052-IDE together with the open source and freely usable SDCC compiler to go with it.