RFM products are now Murata products. RF1238 • • • • • Ideal Front-End Filter for 318.0 MHz Wireless Receivers Low-Loss, Coupled-Resonator Quartz Design Simple External Impedance Matching Rugged TO39 Hermetic Package Complies with Directive 2002/95/EC (RoHS) Pb 318.0 MHz SAW Filter The RF1238 is a low-loss, compact, and economical surface-acoustic-wave (SAW) filter designed to provide front-end selectivity in 318.0 MHz receivers. Receiver designs using this filter include superhet with 10.7 MHz or 500 kHz IF, direct conversion and superregen. Typical applications of these receivers are wireless remote-control and security devices operating in the USA under FCC Part 15, in Canada under DoC RSS-210, and in Australia. This coupled-resonator filter (CRF) uses selective null placement to provide suppression, typically greater than 40 dB, of the LO and image spurious responses of superhet receivers with 10.7 MHz IF. Murata’s advanced SAW design and fabrication technology is utilized to achieve high performance and very low loss with simple external impedance matching (not included). Quartz construction provides excellent frequency stability over a wide temperature range. Characteristic Nominal Frequency at 25°C Sym Absolute Frequency Tolerance from 318.0 MHz Insertion Loss 3 dB Bandwidth Rejection fC ΔfC Notes 1 BW3 1, 2 at fC - 21.4 MHz (Image) 1 External Impedance Match kHz dB 500 700 800 kHz 40 50 15 40 Turnover Temperature TO 30 Turnover Frequency fO 3, 4 L C +85 °C 60 °C kHz 0.032 ppm/°C2 ≤10 ppm/yr 86 nH 6.8 on Pin 1 Side, 4.7 on Pin 2 Side pF 5 1 45 fC+4 FTC IfAI Shunt Capacitance (Tab Side, Non Tab Side) dB 80 -40 Series Inductance MHz 3.5 TC Frequency Aging Units 1.7 Operating Case Temp. Freq. Temp. Coefficient Maximum ±80 Ultimate Temp. Characteristics Typical 318.0 1, 2 IL at fC - 10.7 MHz (LO) Minimum TO39-3 Case Lid Symbolization (in addition to Lot and/or Date Codes) RFM RF1238 CAUTION: Electrostatic Sensitive Device. Observe precautions for handling. NOTES: 1. 2. 3. 4. 5. 6. 7. 8. Unless noted otherwise, all measurements are made with the filter installed in the specified test fixture which is connected to a 50 Ω test system with VSWR ≤ 1.2:1. The test fixture L and C are adjusted for minimum insertion loss at the filter center frequency, fc. Note that insertion loss, bandwidth, and passband shape are dependent on the impedance matching component values and quality. The frequency fc is defined as the midpoint between the 3dB frequencies. Where noted, specifications apply over the entire specified operating temperature range. The turnover temperature, TO, is the temperature of maximum (or turnover) frequency, fo. The nominal frequency at any case temperature, Tc, may be calculated from: f = fo [1 - FTC (To - Tc)2]. Frequency aging is the change in fc with time and is specified at +65°C or less. Aging may exceed the specification for prolonged temperatures above +65°C. Typically, aging is greatest the first year after manufacture, decreasing significantly in subsequent years. The design, manufacturing process, and specifications of this device are subject to change without notice. One or more of the following U.S. Patents apply: 4,54,488, 4,616,197, and others pending. All equipment designs utilizing this product must be approved by the appropriate government agency prior to manufacture or sale. ©2010-2015 by Murata Electronics N.A., Inc. RF1238 (R) 4/6/15 Page 1 of 2 www.murata.com Absolute Maximum Ratings Rating Value Units Incident RF Power +13 dBm DC Voltage Between Any Two Pins (Observe ESD Precautions) ±30 VDC -40 to +85 °C Case Temperature5 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 10.7 MHz IF. . 0 dB -1 0 dB -10 LO -2 Amplitude Response Amplitude Response -20 -30 -40 Image -50 -3 -4 Minimum 3dB Passband at 25 o C -5 -6 -60 -7 -70 -8 -80 100 KHz/div Frequency 5 MHz/div Frequency Case Design Electrical Connections C Pin 1 Bottom View Connection Pin 1 Pin 2 Input or Output 2 Output or Input 3 Case Ground G B H F E A Pin 3 D (3 places) J (2 places) Typical Test Circuit Dimensions L From 50Ω Network Analyzer L 1 C 2 3 C To 50 Ω Network Analyzer Millimeters Min 9.40 B 3.18 2.50 Min Max 0.370 0.125 0.098 0.138 0.46 Nominal 0.018 Nominal E 5.08 Nominal 0.200 Nominal F 2.54 Nominal 0.100 Nominal G 2.54 Nominal 0.100 Nominal J Page 2 of 2 3.50 Inches D H ©2010-2015 by Murata Electronics N.A., Inc. RF1238 (R) 4/6/15 Max A C 45° 1.02 1.40 0.040 0.055 www.murata.com