®
RO2131D
314.350 MHz
SAW
Resonator
•
•
•
Ideal for 314.350 MHz Automotive-Keyless-Entry Transmitters
Very Low Series Resistance
Quartz Stability
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
Input Power Level
DC Voltage
Storage Temperature
Value
0
12
-40 to +85
Units
dBm
VDC
°C
SM3838-6 Case
3.8 X 3.8
Typical
Maximum
314.400
±50
1.6
6516
1066
10
25
f
C
0.032
10
ppm/°C
2
ppm/yr
MΩ
20.00
Ω
µH
fF
pF
nH
65.00
4.00
40
°C
2.5
Units
MHz
kHz
dB
Electrical Characteristics
Characteristic
Absolute Frequency
Tolerance from 314.350 MHz
Insertion Loss
Quality Factor
Temperature Stability
Unloaded Q
50
Ω
Loaded Q
Turnover Temperature
Turnover Frequency
Frequency Temperature Coefficient
Frequency Aging
RF Equivalent RLC Model
Absolute Value during the First Year
Motional Resistance
Motional Inductance
Motional Capacitance
Shunt Static Capacitance
Test Fixture Shunt Inductance
Lid Symbolization
Standard Reel Quantity
Reel Size 7 Inch
Reel Size 13 Inch
DC Insulation Resistance between Any Two Terminals
R
M
L
M
C
M
C
O
L
TEST
5, 6, 9
2, 7
2.0
5, 7, 9
Sym
f
C
∆f
C
IL
Q
U
Q
L
T
O
f
O
FTC
|f
A
|
1, 6
5
1.0
6, 7, 8
Notes
2, 3, 4, 5
2, 5, 6
5, 6, 7
Minimum
314.300
Frequency (+25 °C)
3.6
64.6
440 / YWWS
500 Pieces / Reel
3000 Pieces / Reel
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
Notes:
1.
Frequency aging is the change in f
C
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 subse-
quent years.
The center frequency, f
C
, is measured at the minimum insertion loss point,
IL
MIN
, with the resonator in the 50
Ω
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
.
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 T
C
= +25°C±2°C.
The design, manufacturing process, and specifications of this device are subject
to change without notice.
7.
8.
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
.
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
.
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.
2.
9.
3.
4.
5.
6.
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
RO2131D-040103
Page 1 of 2
314.350 MHz
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.
Pin
1
2
3
4
5
6
SAW Resonator
Connection
NC
Terminal
NC
NC
Terminal
NC
Power Test
P
INCIDENT
50
Ω
Source
at F
C
P
REFLECTED
Low-Loss
Matching
Network to
50
Ω
1
6
2
3
5
4
Typical Application Circuits
B
1
6
6
1
Modulation
Input
C
G
H
Typical Low-Power Transmitter Application
200k
Ω
C1
L1
(Antenna)
+9VDC
47
A 2
5
E
5
2
I
2
3
4
3
4
3
6
1
5
4
C2
D
J
ROXXXXC
Bottom View
RF Bypass
470
Typical Local Oscillator Application
Output
Case Dimensions
Dimension
A
B
C
D
E
G
H
I
J
Min
3.6
3.6
mm
Nom
3.8
3.8
1.0
2.54
1.0
2.0
0.6
1.8
Max
4.0
4.0
1.5
Min
0.14
0.14
Inches
Nom
0.15
0.15
0.06
0.04
0.10
0.04
0.08
0.02
0.07
Max
0.157
0.157
0.60
200k
Ω
+VDC
C1
L1
+VDC
1
6
2
3
5
4
C2
ROXXXXC
Bottom View
RF Bypass
Equivalent LC Mode
l
0.05 pF*
Co = Cp + 0.05 pF
Cp
*Case Parasitics
Typical Test Circuit
The test circuit inductor, L
TEST
, is tuned to resonate with the static
capacitance, C
O
, at F
C
.
Electrical Test
Rm
Lm
Cm
Temperature Characteristics
The curve shown on the right accounts for resonator contribution only and
does not include LC component temperature contributions
.
f
C
= f
O
, T
C
= T
O
6
1
0
2
0
-50
-100
-150
-200
0 +20 +40 +60 +80
From 50
Ω
Network Analyzer
5
To 50
Ω
Network Analyzer
4
3
(f-fo ) / fo (ppm)
-50
-100
-150
-200
-80 -60 -40 -20
∆
T = T
C
- T
O
( °C )
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
RO2131D-040103
Page 2 of 2
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