Micrel's Programmable Receiver Boasts Jam Avoidance

(Product News, 27 Feb 2008)

Micrel Inc. has launched what it claims to be the world's first programmable receiver featuring jam avoidance—the MICRF218, which is part of Micrels QwikRadio family—targeted at garage door openers and tire pressure monitoring systems. The device is said to be the industry's first integrated ASK/OOK receiver with selectable IF bandwidth for 300MHz to 450MHz operation.

The MICRF218 can escape from a jamming source and migrate to an alternate frequency. This is a crucial feature due to recent homeland security measures deploying a new mobile radio system, which presents the possibility of jamming at the 390MHz 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°C to 125°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.

Click here for more information on the MICRF218 receiver

Click here for more information on Micrel