Application Hint 31 Micrel Application Hint 31 Ceramic Resonators for the MICRF001 by Tom Yestresbsky Ceramic Resonators and Series Resistance Murata Part Number (Leaded Package) Ref. Freq. fT TX Freq. fTX An on-board oscillator within the MICRF001, together with an externally connected resonator or clock signal, establishes the operating frequency of the MICRF001. When using a resonator (ceramic resonator or crystal), its series resistance should be minimized to the extent possible, to ensure oscillation. In case where the resonator series resistance is too great, the oscillator may oscillate at a diminished peak-topeak level, or may fail to oscillate entirely. Micrel recommends that series resistances for ceramic resonators and crystals not exceed 50Ω and 100Ω, respectively. CSA2.44MG05051 2.44MHz 315MHz CSA3.00MG05051 3.00MHz 387MHz CSA3.02MG05051 3.02MHz 390MHz CSA3.07MG05051 3.07MHz 396MHz CSA3.21MG05051 3.21MHz 414MHz CSA3.24MG05051 3.24MHz 418MHz CSA3.31MG05051 3.31MHz 427MHz CSA3.36MG05051 3.36MHz 433.9MHz Murata Part Number (Surface-Mount Package) Ref. Freq. fT TX Freq. fTX CSAC2.44MGC05051-TC 2.44MHz 315MHz CSAC3.00MGC05051-TC 3.00MHz 387MHz CSAC3.02MGC05051-TC 3.02MHz 390MHz CSAC3.07MGC05051-TC 3.07MHz 396MHz CSAC3.21MGC05051-TC 3.21MHz 414MHz CSAC3.24MGC05051-TC 3.24MHz 418MHz CSAC3.31MGC05051-TC 3.31MHz 427MHz CSAC3.36MGC05051-TC 3.36MHz 433.9MHz Ceramic Resonators Availability A family of ceramic resonators, manufactured by Murata Electronics, and providing low series resistance, has been characterized with the MICRF001 in SWP mode. These standard values (shown in the table below) provide a convenient solution for many common frequencies worldwide. Sample quantities of these standard values are stocked by Murata Electronics for rapid-protyping purposes (www.murata.com). Murata can also provide resonators for custom frequencies and high-volume applications. QwikRadio is a trademark of Micrel, Inc. The QwikRadio ICs were developed under a partnership agreement with AIT of Orlando, Florida Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com July 1999 1 Application Hint 31 Application Hint 31 Micrel MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 1999 Micrel Incorporated Application Hint 31 2 July 1999