®
RO2118A
•
•
•
Ideal for 318 MHz Transmitters
Very Low Series Resistance
Quartz Stability
Surface-Mount, Ceramic Case with 21 mm2 Footprint
318.0 MHz
SAW
•
•
Complies with Directive 2002/95/EC (RoHS)
Resonator
The RO2118A is a true one-port, surface-acoustic-wave (SAW) resonator in a surface-mount, ceramic case.
It provides reliable, fundamental-mode, quartz frequency stabilization of fixed-frequency transmitters operat-
ing at 318 MHz. This SAW is designed for AM transmitters remote control and wireless security applications
operating in the USA under FCC Part 15, in Canada under DoC RSS-210, and in Italy.
Absolute Maximum Ratings
Rating
Value
+0
Units
dBm
VDC
°C
CW RF Power Dissipation
DC Voltage Between Terminals
Case Temperature
±30
-40 to +85
260
SM-2 Case
Soldering Temperature (10 seconds / 5 cycles max.)
°C
Electrical Characteristics
Characteristic
Sym
Notes
Minimum
Typical
Maximum
Units
f
Frequency (+25 °C)
Nominal Frequency
317.900
318.100
MHz
kHz
dB
C
2, 3, 4, 5
Df
Tolerance from 318.000 MHz
±100
1.5
C
Insertion Loss
Quality Factor
IL
2, 5, 6
5, 6, 7
0.7
16,900
1,300
25
Q
Unloaded Q
U
Q
T
50 W Loaded Q
L
Temperature Stability
Turnover Temperature
Turnover Frequency
10
1.0
2.9
40
°C
O
f
f
6, 7, 8
O
C
2
Frequency Temperature Coefficient
Absolute Value during the First Year
FTC
0.032
10
ppm/°C
|f |
Frequency Aging
1, 6
5
ppm/yr
MW
W
A
DC Insulation Resistance between Any Two Terminals
R
RF Equivalent RLC Model
Motional Resistance
8
19
M
L
Motional Inductance
5, 6, 7, 9
72.2067
3.46904
3.2
µH
M
C
Motional Capacitance
Transducer Static Capacitance
fF
M
C
5, 6, 9
2, 7
3.5
pF
O
L
Test Fixture Shunt Inductance
Lid Symbolization
80
nH
TEST
108
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
Notes:
1.
2.
Frequency aging is the change in fC with time and is specified at +65°C or less.
8.
Turnover temperature, TO, is the temperature of maximum (or turnover) fre-
quency, fO. The nominal frequency at any case temperature, TC, may be calcu-
lated from: f = fO [1 - FTC (TO -TC)2]. Typically oscillator TO is approximately
equal to the specified resonator TO.
This equivalent RLC model approximates resonator performance near the reso-
nant frequency and is provided for reference only. The capacitance CO is the
static (nonmotional) capacitance between the two terminals measured at low
frequency (10 MHz) with a capacitance meter. The measurement includes para-
sitic capacitance with "NC” pads unconnected. Case parasitic capacitance is
approximately 0.05 pF. Transducer parallel capacitance can by calculated as:
Aging may exceed the specification for prolonged temperatures above +65°C.
Typically, aging is greatest the first year after manufacture, decreasing in subse-
quent years.
The center frequency, fC, is measured at the minimum insertion loss point,
9.
ILMIN, with the resonator in the 50 W test system (VSWR £ 1.2:1). The shunt
inductance, LTEST, is tuned for parallel resonance with CO at fC. Typically, fOS-
CILLATOR or fTRANSMITTER is approximately equal to the resonator fC.
One or more of the following United States patents apply: 4,454,488 and
4,616,197.
Typically, equipment utilizing this device requires emissions testing and govern-
ment approval, which is the responsibility of the equipment manufacturer.
Unless noted otherwise, case temperature TC = +25°C±2°C.
The design, manufacturing process, and specifications of this device are subject
to change without notice.
3.
4.
C
P » CO - 0.05 pF.
5.
6.
7.
Derived mathematically from one or more of the following directly measured
parameters: fC, IL, 3 dB bandwidth, fC versus TC, and CO.
RF Monolithics, Inc.
RFM Europe
Phone: (972) 233-2903
Phone: 44 1963 251383
Fax: (972) 387-8148
Fax: 44 1963 251510
E-mail: info@rfm.com
http://www.rfm.com
RO2118A-061901
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©1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc.
RFM [ RF MONOLITHICS, INC ]
