• Ideal Front-End Filter for 916.5 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
The RF1181 is a low-loss, compact, and economical surface-acoustic-wave (SAW) filter designed to provide
front-end selectivity in 916.5 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 wire-
less remote-control and security devices operating in the USA under FCC Part 15 and in Canada under DoC
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. 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). Quartz construction provides excellent frequency stabil-
ity over a wide temperature range.
Center Frequency at 25°C Absolute Frequency
3 dB Bandwidth
Tolerance from 916.500 MHz
at fC - 21.4 MHz (Image)
at fC - 10.7 MHz (LO)
Operating Case Temp.
Freq. Temp. Coefficient
Absolute Value during the First Year
Lid Symbolization (in addition to Lot and/or Date Codes)
600 750 1000
Coilcraft 8.2 nH Chip Inductor
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
1. 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.
2. The frequency fc is defined as the midpoint between the 3dB frequencies.
3. Unless noted otherwise, specifications apply over the entire specified operating temperature range.
4. 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].
5. 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.
6. The design, manufacturing process, and specifications of this device are subject to change without notice.
7. One or more of the following U.S. Patents apply: 4,54,488, 4,616,197, and others pending.
8. All equipment designs utilizing this product must be approved by the appropriate government agency prior to manufacture or sale.
RF Monolithics, Inc. Phone: (972) 233-2903
Fax: (972) 387-8148
Phone: 44 1963 251383
Fax: 44 1963 251510
©1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc.
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