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©2008 by RF Monolithics, Inc. RO3118D - 3/27/08
Electrical Characteristics
Characteristic Sym Notes Minimum Typical Maximum Units
Frequency (+25 °C) Absolute Frequency fC2, 3, 4, 5 317.925 318.075 MHz
Tolerance from 318.0 MHz ΔfC±75 kHz
Insertion Loss IL 2, 5, 6 1.4 2.0 dB
Quality Factor Unloaded Q QU12900
50W Loaded Q QL1800
Temperature Stability Turnover Temperature TO6, 7, 8 10 25 40 °C
Turnover Frequency fOfC
Frequency Temperature Coefficient FTC 0.032 ppm/°C2
Frequency Aging Absolute Value during the First Year |fA|1, 6 10 ppm/yr
DC Insulation Resistance between Any Two Terminals 5 1.0 MΩ
RF Equivalent RLC Model Motional Resistance RM5, 7, 9 16 Ω
Motional Inductance LM101 µH
Motional Capacitance CM2.4 fF
Shunt Static Capacitance CO5, 6, 9 2.8 pF
Test Fixture Shunt Inductance LTEST 2, 7 86 nH
Lid Symbolization 716 // YWWS
Standard Reel Quantity Reel Size 7 Inch 500 Pieces / Reel
Reel Size 13 Inch 3000 Pieces / Reel
• Ideal for 318 MHz Automotive-Keyless-Entry Transmitters
• Very Low Series Resistance
• Quartz Stability
• Complies with Directive 2002/95/EC (RoHS)
The RO3118D is a true one-port, surface-acoustic-wave (SA W) resonator in a surface-mount, ceramic case.
It provides reliable, fundamental-mode, quartz frequency stabilization of local oscillators operating at
approximately 318 MHz.
Absolute Maximum Ratings
Rating Value Units
Input Power Level 0 dBm
DC Voltage 12 VDC
Storage Temperature -40 to +85 °C
Soldering Temperature (10 seconds / 5 cycles max.) 260 °C
318.0 MHz
SAW
Resonator
RO3118D
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
Notes:
1. 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 in subsequent years .
2. The center frequency, fC, is measured at the minimum insertion loss point,
ILMIN, with the res onator in the 50 Ω test system (VSWR ≤ 1.2:1). The
shunt inductance, LTEST, is tuned for parallel resonance with CO at fC.
Typi cally, fOSCILLATOR or fTRANSMITTER is approx imately equal to the
resonator fC.
3. One or more of the following United Sta tes patents apply: 4,454,488 and
4,616,197.
4. Typically, equipment utilizing this devic e requires emissions testing and
government app roval, which is the responsibility of the equipment
manufacturer.
5. Unless noted otherwis e, case temperature TC= +25°C±2°C.
6. The design, manufacturing process , and spec ifications of this device are
subject to change without no tice.
7. Derived mat hematically from one or more of the following directly
measured parameters: fC, IL, 3 dB bandwidth, fC versu s TC, and CO.
8. Turnover temperature, TO, is the temperatur e of maximum (or turnover)
frequenc y, fO. The nomina l frequenc y at an y case te mperature, TC, may be
calculated from: f = fO[1 - FTC (TO-TC)2]. Typically oscillator TO is
approximately equal to the spec ified resonator TO.
9. This equiv alent RLC model approximates resonator performance near the
resonan t frequen cy and is provided for refer ence o nly. The capaci tanc e CO
is the static (nonmotional) capacitance between the two terminals
measured at low frequency (10 MHz) with a capacitance meter. The
measureme nt includes p arasitic cap acitanc e with "NC” pads unconne cted.
Case pa r as itic capacitance is approx imately 0.05 pF. Transducer parallel
capacitance can by calculated as: CP≈CO-0.05pF.
SM3838-6 Case
3.8 X 3.8
Pb
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©2008 by RF Monolithics, Inc. RO3118D - 3/27/08
-80 -60 -40 -20 0 +20 +40 +60
0
-50
-100
-150
+80
-200
0
-50
-100
-150
-200
f
C
= f
O
, T
C
= T
O
Δ
T = T
C
- T
O
( °C )
(f-foo
)/f(ppm)
0.05 pF*
0.05 pF
Cp
Co+
=
*Case Parasitics
Cp
Rm Lm Cm
Equivalent LC Model
Tempera ture Ch arac ter isti cs
The curve shown on the right accounts for resonator contribution only and
does not include LC component temperature contributions.
Pin Connection
1NC
2 Terminal
3NC
4NC
5 Terminal
6NC
Power Test
Electrical Connections
The SAW resonator is bidirectional and
may be installed with either orientation.
The two terminals are interchangeable
and unnumbered. The callout NC
indicates no internal connection. The NC
pads assist with mechanical positioning
and stability . External grounding of the NC
pads is recommended to help reduce
parasitic capacitance in t he circuit.
Typical Tes t Circuit
The test circuit inductor, LTEST, is tuned to resonate with the static
capacitance, CO, at FC.
Electri cal Tes t
Typical Application Circuits
Case Dimensions
Dimension mm Inches
Min Nom Max Min Nom Max
A3.60 3.80 4.0 0.14 0.15 0.16
B3.60 3.80 4.0 0.14 0.15 0.16
C1.00 1.20 1.40 0.04 0.05 0.055
D0.95 1.10 1.25 0.033 0.043 0.05
E2.39 2.54 2.69 0.090 0.10 0.110
G0.90 1.0 1.10 0.035 0.04 0.043
H1.90 2.0 2.10 0.75 0.08 0.83
I0.50 0.6 0.70 0.020 0.024 0.028
J1.70 1.8 1.90 0.067 0.07 0.075
Low-Loss
Matching
Network to
50 Ω
50 Ω Source
at FC
PINCIDENT
PREFLECTED
2 3
6 5 4
1
Modulation
Input
ROXXXXC
Bottom View
200k Ω
C1
L1
(Antenna)
47
+9VDC
C2
RF Bypass
470
Typical Low-Power T ransmitter Application
2 3
6 5 4
1
+VDC
ROXXXXC
Bottom View
200k Ω
C1
L1
+VDC
C2
RF Bypass
Typica l Local Oscillator Application Output
2 3
6 5 4
1
1
2
3
6
5
4
1
2
3
6
5
4
A
BC
DJ
E
GH
I