RF Monolithics, Inc.
Phone: (972) 233-2903
Fax: (972) 387-8148
E-mail: info@rfm.com
Page 1 of 2
RFM Europe
Phone: 44 1963 251383
Fax: 44 1963 251510
http://www.rfm.com
1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc.
RO2131D-040103
Electrical Characteristics
Characteristic
Sym
Notes
Minimum
Typical
Maximum
Units
Frequency (+25 C)
Absolute Frequency
f
C
2, 3, 4, 5
314.300
314.400
MHz
Tolerance from 314.350 MHz
f
C
50
kHz
Insertion Loss
IL
2, 5, 6
1.6
2.5
dB
Quality Factor
Unloaded Q
Q
U
5, 6, 7
6516
50
Loaded Q
Q
L
1066
Temperature Stability
Turnover Temperature
T
O
6, 7, 8
10
25
40
C
Turnover Frequency
f
O
f
C
Frequency Temperature Coefficient
FTC
0.032
ppm/C
2
Frequency Aging
Absolute Value during the First Year
|f
A
|
1, 6
10
ppm/yr
DC Insulation Resistance between Any Two Terminals
5
1.0
M
RF Equivalent RLC Model
Motional Resistance
R
M
5, 7, 9
20.00
Motional Inductance
L
M
65.00
H
Motional Capacitance
C
M
4.00
fF
Shunt Static Capacitance
C
O
5, 6, 9
2.0
3.6
pF
Test Fixture Shunt Inductance
L
TEST
2, 7
64.6
nH
Lid Symbolization
440 / YWWS
Standard Reel Quantity Reel Size 7 Inch
500 Pieces / Reel
Reel Size 13 Inch
3000 Pieces / Reel
Ideal for 314.350 MHz Automotive-Keyless-Entry Transmitters
Very Low Series Resistance
Quartz Stability
Complies with Directive 2002/95/EC (RoHS)
The RO2131D 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 local oscillators operating at approx-
imately 314.350 MHz. This SAW was designed for AM transmitters in automotive-keyless-entry applications
operating in the USA under FCC Part 15, in Canada under DoC RSS-210, and in Italy.
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
314.350 MHz
SAW
Resonator
RO2131D
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
Notes:
1.
Frequency aging is the change in f
C
with time and is specified at +65C or less.
Aging may exceed the specification for prolonged temperatures above +65C.
Typically, aging is greatest the first year after manufacture, decreasing in subse-
quent years.
2.
The center frequency, f
C
, is measured at the minimum insertion loss point,
IL
MIN
, with the resonator in the 50
test system (VSWR
1.2:1). The shunt
inductance, L
TEST
, is tuned for parallel resonance with C
O
at f
C
. Typically, f
OS-
CILLATOR
or f
TRANSMITTER
is approximately equal to the resonator f
C
.
3.
One or more of the following United States patents apply: 4,454,488 and
4,616,197.
4.
Typically, equipment utilizing this device requires emissions testing and govern-
ment approval, which is the responsibility of the equipment manufacturer.
5.
Unless noted otherwise, case temperature T
C
= +25C2C.
6.
The design, manufacturing process, and specifications of this device are subject
to change without notice.
7.
Derived mathematically from one or more of the following directly measured
parameters: f
C
, IL, 3 dB bandwidth, f
C
versus T
C
, and C
O
.
8.
Turnover temperature, T
O
, is the temperature of maximum (or turnover) fre-
quency, f
O
. The nominal frequency at any case temperature, T
C
, may be calcu-
lated from: f = f
O
[1 - FTC (T
O
-T
C
)
2
]. Typically
oscillator T
O
is approximately
equal to the specified
resonator T
O
.
9.
This equivalent RLC model approximates resonator performance near the reso-
nant frequency and is provided for reference only. The capacitance C
O
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:
C
P
C
O
- 0.05 pF.
SM3838-6 Case
3.8 X 3.8
Pb
314.350 MHz SAW Resonator
RF Monolithics, Inc.
Phone: (972) 233-2903
Fax: (972) 387-8148
E-mail: info@rfm.com
Page 2 of 2
RFM Europe
Phone: 44 1963 251383
Fax: 44 1963 251510
http://www.rfm.com
1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc.
RO2131D-040103
-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
T =
T
C
- T
O
( C )
(f-
f o
o
) /
f
(ppm
)
0.05 pF*
0.05 pF
Cp
Co
+
=
*Case Parasitics
Cp
Rm
Lm
Cm
Equivalent LC Mode
l
Temperature Characteristics
The curve shown on the right accounts for resonator contribution only and
does not include LC component temperature contributions
.
Pin
Connection
1
NC
2
Terminal
3
NC
4
NC
5
Terminal
6
NC
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 indi-
cates 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 the circuit.
Typical Test Circuit
The test circuit inductor, L
TEST
, is tuned to resonate with the static
capacitance, C
O
, at F
C
.
Electrical Test
Typical Application Circuits
From 50
Network Analyzer
To 50
Network Analyzer
2
3
6
5
4
1
Low-Loss
Matching
Network to
50
50
Source
at F
C
P
INCIDENT
P
REFLECTED
2 3
6 5 4
1
Modulation
Input
ROXXXXC
Bottom View
200k
C1
L1
(Antenna)
47
+9VDC
C2
RF Bypass
470
Typical Low-Power Transmitter Application
2 3
6 5 4
1
+VDC
ROXXXXC
Bottom View
200k
C1
L1
+VDC
C2
RF Bypass
Typical Local Oscillator Application
Output
2 3
6 5 4
1
1
2
3
6
5
4
1
2
3
6
5
4
A
B
C
D
J
E
G
H
I
Case Dimensions
Dimension
mm
Inches
Min
Nom
Max
Min
Nom
Max
A
3.60
3.80
4.0
0.14
0.15
0.16
B
3.60
3.80
4.0
0.14
0.15
0.16
C
1.00
1.20
1.40
0.04
0.05
0.055
D
0.95
1.10
1.25
0.037
0.043
0.05
E
2.39
2.54
2.69
0.090
0.10
0.110
G
0.90
1.0
1.10
0.035
0.04
0.043
H
1.90
2.0
2.10
0.75
0.08
0.83
I
0.50
0.6
0.70
0.020
0.024
0.028
J
1.70
1.8
1.90
0.067
0.07
0.075
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