rf monolithics, inc. phone: (972) 233-2903 fax: (972) 387-9148 e-mail: info@rfm.com page 1 of 2 rfm europe phone: 44 1963 251383 fax: 44 1963 251510 http://www.rfm.com ?1999 by rf monolithics, inc. the stylized rfm logo are registered trademarks of rf monolithics, inc. RF1238B-101599 electrical characteristics characteristic sym notes minimum typical maximum units nominal frequency f c 2, 4, 5, 6 318.00 mhz insertion loss il 3, 4, 7 5.0 8.5 db 3 db passband bw 3 2, 3, 4, 7 khz 3 db rejectband bw 3 2, 3, 4, 7 135 khz rejection at f c - 21.4 mhz (image) 4 40 50 db at f c - 10.7 mhz (lo) 15 30 ultimate 80 temperature operating case temp. t c 3, 7, 8 -40 +85 c turnover temperature t o 15 25 40 c turnover frequency f o f c mhz freq. temp. coefficient ftc 0.032 ppm/c 2 frequency aging absolute value during the first year |fa| 3 <10 ppm/yr external impedance series inductance l 1, 7 47 nh shunt capacitance c 5-18 pf lid symbolization (in addition to lot and/or date codes) RF1238B sm8558-8 case ? ideal front-end filter for european wireless receivers ? low-loss, coupled-resonator quartz design ? simple external impedance matching ? surface-mount ceramic case with 52mm 2 footprint the RF1238B is a low-loss, compact, and economical surface-acoustic-wave (saw) filter designed to pro- vide front-end selectivity in 318.0mhz receivers. receiver designs using this filter include superhet with 10.7mhz or 500khz if, direct conversion and superregen. typical applications of these receivers are wire- less remote-control and security devices operating in the usa under fcc part 15, in canada under doc rss210, and in australia. this coupled-resonator filter (crf) uses selective null placement to provide suppression, typically greater than 40db, of the lo and image spurious responses of superhet receivers with 10.7mhz if. rfm?s ad- vanced saw design and fabrication technology is utilized to achieve high performance and very low loss with simple external impedance matching (not included). our new patent pending solder seal process utilizes a faraday shield lid, which improves out of band rejection. 318.0 mhz saw filter RF1238B caution: electrostatic sensitive device. observe precautions for handling. notes: 1. typical demonstration circuit shown is for sm8558-8 solder seal filters. 2. passband and reject bands are specified in reference to f c . 3. all characteristics are specified over the operating temperature range and typical aging is 10 years. 4. unless noted otherwise, all measurements are made with the filter installed in the specified test fixture. note that insertions loss, bandwidth, and passband shape are dependent on the impedance matching component values and quality. demonstration circuits are available for c onfirmation of device performance. 5. one or more of the following u.s. patents apply: 4,454,488; 4,616,197; and others pending. 6. all equipment designs utilizing this product must be approved by the appropriate government agency prior to manufacture or sale. 7. the design, manufacturing process, and specifications of this device are subject to change without notice. 8. the turnover temperature, to, is the temperature of maximum (or turnover) frequency, f o . the nominal frequency at any case temperature, t c , out- side the operating temperature range may be calculated from: f=f o [1-ftc(t o -t c ) 2 ].
318.0 mhz saw filter rf monolithics, inc. phone: (972) 233-2903 fax: (972) 387-9148 e-mail: info@rfm.com page 2 of 2 rfm europe phone: 44 1963 251383 fax: 44 1963 251510 http://www.rfm.com ?1999 by rf monolithics, inc. the stylized rfm logo are registered trademarks of rf monolithics, inc. RF1238B-101599 typical filter response typical filter responses are shown below. the actual response is dependent on external impedance matching and circuit layout. illustrated frequencies and minimum rejection for lo and image are shown only for superhet receivers with 10.7mhz if. absolute maximum ratings rating value units incident rf power +13 dbm dc voltage between any 2 pins (observe esd precautions) 30 vdc case temperature 1 -40 to +85 c electrical connections typical test circuit case design dimensions millimeters inches min max min max a 8.71 0.343 b 6.04 0.238 c 2.03 0.080 d 0.79 nominal 0.031 nominal e 1.14 nominal 0.045 nominal f 1.98 nominal 0.078 nominal g 0.79 nominal 0.031 nominal h 6.91 0.040 k 4.24 0.167 m 0.81 0.032 n 2.54 nominal 0.100 nominal p 1.91 nominal 0.075 nominal pin connection 1 input 2 ground 3 output return 4 case ground 5 output ground 7 input return 8 case ground
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