RF1238 데이터 시트보기 (PDF) - RF Monolithics, Inc
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RF1238 Datasheet PDF : 2 Pages
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• Ideal Front-End Filter for 318.0 MHz Wireless Receivers
• Low-Loss, Coupled-Resonator Quartz Design
• Simple External Impedance Matching
• Rugged TO39 Hermetic Package
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 wire-
less 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. 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 stability
over a wide temperature range.
RF1238
318.0 MHz
SAW Filter
TO39-3 Case
Electrical Characteristics
Characteristic
Nominal Frequency at 25°C Absolute Frequency
Insertion Loss
Tolerance from 318.0 MHz
3 dB Bandwidth
Rejection
at fC - 21.4 MHz (Image)
at fC - 10.7 MHz (LO)
Ultimate
Temp. Characteristics
Operating Case Temp.
Turnover Temperature
Turnover Frequency
Freq. Temp. Coefficient
Frequency Aging
External Impedance Match Series Inductance
Shunt Capacitance (Tab Side, Non Tab Side)
Lid Symbolization (in addition to Lot and/or Date Codes)
Sym
fC
∆fC
IL
BW3
TC
TO
fO
FTC
IfAI
L
C
Notes
1, 2
1
1, 2
1
3, 4
5
1
Minimum
Typical
Maximum
318.0
±80
1.7
3.5
500
700
800
40
50
15
40
80
-40
+85
30
45
60
fC+4
0.032
≤10
86
6.8 on Pin 1 Side, 4.7 on Pin 2 Side
RFM RF1238
Units
MHz
kHz
dB
kHz
dB
°C
°C
kHz
ppm/°C2
ppm/yr
nH
pF
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
Notes:
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. Where noted, 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
RFM Europe
Phone: 44 1963 251383
Fax: 44 1963 251510
©1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc.
E-mail: info@rfm.com
http://www.rfm.com
RF1238-102401
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