Micrel rolls out “worlds first” programmable receiver with jam avoidance
(Top News, 07 Mar 2008 )
Micrel, an industry leader in analog, high bandwidth and Ethernet IC solutions, has launched what’s said to be the worlds first programmable receiver featuring jam avoidance. The MICRF218, which is part of Micrels QwikRadio family, is targeted at garage door openers and tire pressure monitoring systems. It is the worlds first integrated ASK/OOK receiver with selectable IF bandwidth for 300 to 450 MHz operation. The IC is currently available in volume with pricing starting at $1.71 for 10K quantities.
The MICRF218 is unique for its ability to escape from a jamming source and migrate to an alternate frequency, stated John Lee, director of mixed-signal and RF products, Micrel. This is a crucial feature due to recent homeland security measures deploying a new mobile radio system. This new radio system presents the possibility of jamming at the 390 MHz frequency, a frequency also commonly used by garage door remote controls. The MICRF218 receiver system can avoid jamming by switching to a quieter frequency.
The MICRF218 can accommodate two reference crystals with the use of an external switch. It features a fully integrated IF section with built-in image rejection. The IF section has dual IF bandwidths that are externally selectable. In addition, a wide IF bandwidth can be chosen for backward compatibility with older transmitters that are LC-based. Wide IF bandwidth allows the receiver to capture a signal that slightly deviates from the intended communication frequency, or one can select a narrow IF bandwidth that operates with a crystal-based transmitter to improve selectivity to increase communication distance. There is no sacrifice of performance with either option.
For tire pressure monitoring system applications, a -40 to +125 deg-C operating temperature range can cause significant frequency deviation in the transmitter. The MICRF218AYQS in wide IF bandwidth mode can accommodate transmitter signal drift due to temperature changes in the operating environment.
