RF Monolithics announced the initial release of coupled-resonator filters in a 5mm x 5mm surface-mount package. The initial products are in the 433.92 MHz and 315 MHz frequencies. One application for the filters is in RFID tags, the company said. The filters previously had been available in larger packages and in the company's standard TO39 metal can package. The surface-mount package is being used increasingly in receiver front-end filters, the company said.