RF transmitter extends battery life with better performance

May 17, 2012 // By Paul Buckley
Semtech Corporation has expanded its RFIC platform with a fully integrated, low cost FSK/OOK radio transmitter designed to replace a surface acoustic wave-based resonator transmitters in garage door openers, remote keyless entry and other consumer remote control systems.

The SX1243 features a fractional-N phase lock loop (PLL), which delivers higher performance and more flexibility, while minimizing the BOM cost versus traditional SAW-based resonator designs. The part covers the frequency bands from 310 MHz to 450 MHz, 860 MHz to 870 MHz, as well as 902 MHz to 928 MHz which makes it ideally suited for worldwide operation and regulatory compliance for FCC 15.231/15.247, ARIB and European products under EN 300-220.

To extend battery life, the SX1243 has very low active current consumption of 11 mA at +10 dBm OOK or 15 mA at +10 dBm FSK making it ideal for applications requiring coincell batteries, which only support peak currents up to 20 mA. The low active and sleep currents, combined with fast wake-up times from sleep to TX, make it ideal for applications requiring fast wake-up and long battery lifetime.

The SX1243 features the company’s Power & Go technology that reduces cost dramatically by eliminating the need for a microcontroller (MCU) to configure the part. In Power & Go mode, the part will automatically wake-up for transmission once data transitions are detected on the data pin and automatically return to sleep once the transitions cease. Default configurations for Power & Go are preprogrammed and can be modified for high-volume applications. In other applications where more flexibility to configure parameters is desired, an interface for use with an external MCU is available.

While the SX1243 offers designers the benefit of board space savings, its small size and RoHS & WEEE compliance also contributes to energy conservation and hazardous waste reduction.