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.
RO2073A-1-061901
Electrical Characteristics
Characteristic
Sym
Notes
Minimum
Typical
Maximum
Units
Center Frequency at +25 C
Absolute Frequency
f
C
2,3,4,5
314.925
315.075
MHz
Tolerance from 315.000 MHz
f
C
75
kHz
Insertion Loss
IL
2,5,6
1.3
2.2
dB
Quality Factor
Unloaded Q
Q
U
5,6,7
15,300
50
Loaded Q
Q
L
2,100
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
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
16
29
Motional Inductance
L
M
127.450
H
Motional Capacitance
C
M
2.00299
fF
Shunt Static Capacitance
C
O
5, 6, 9
2.0
2.3
2.6
pF
Test Fixture Shunt Inductance
L
TEST
2, 7
110
nH
Lid Symbolization
111
Ideal for 315 MHz Automotive-Keyless-Entry Transmitters
Very Low Series Resistance
Quartz Stability
Surface-Mount Ceramic Case with 21 mm
2
Footprint
Complies with Directive 2002/95/EC (RoHS)
The RO2073A-1 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
operating at 315 MHz. This SAW is designed specifically 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
CW RF Power Dissipation (See: Typical Test Circuit)
+0
dBm
DC voltage Between Terminals (Observe ESD Precautions.)
30
VDC
Case Temperature
-40 to +85
C
Soldering Temperature (10 seconds / 5 cycles max.)
260
C
315.0 MHz
SAW
Resonator
RO2073A-1
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.
SM-2 Case
315.0 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.
RO2073A-1-061901
Electrical Connections
The SAW resonator is bidirectional and may be in-
stalled 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 recommend-
ed to help reduce parasitic capacitance in the cir-
cuit.
Typical Test Circuit
The test circuit inductor, L
TEST
, is tuned to resonate with the static capaci-
tance, C
O
, at F
C
.
Typical Application Circuits
Equivalent LC Mode
l
Temperature Characteristics
The curve shown on the right
accounts for resonator contri-
bution only and does not in-
clude LC component tempera-
ture contributions
.
Typical Circuit Board
Land Pattern
The circuit board land pattern shown below is one possible design. The op-
timum land pattern is dependent on the circuit board assembly process
which varies by manufacturer. The distance between adjacent land edges
should be at a maximum to minimize parasitic capacitance. Trace lengths
from terminal lands to other components should be short and wide to mini-
mize parasitic series inductances.
Case Design
The case material is black alumina with contrasting symbolization. All pads
are nominally centered with respect to the base and consist of 40 to
70 microinches electroless gold on 60-350 micorinches electroless nickel.
NC
NC
Terminal
Terminal
From 50
Network Analyzer
Network Analyzer
To 50
ELECTRICAL TEST
+9VDC
47
RF Bypass
L1
(Antenna)
C1
C2
200k
Modulation
Input
ROXXXXA
Bottom View
470
Typical Low-Power Transmitter Application
RF Bypass
L1
C1
C2
ROXXXXA
Bottom View
Typical Local Oscillator Application
+VDC
+VDC
Output
Dimensions
Millimeters
Inches
Min
Max
Min
Max
A
5.74
5.99
0.226
0.236
B
3.73
3.99
0.147
0.157
C
1.91
2.16
0.075
0.085
D
0.94
1.10
0.037
0.043
E
0.83
1.20
0.033
0.047
F
1.16
1.53
0.046
0.060
G
0.94
1.10
0.037
0.043
H
0.43
0.59
0.017
0.023
K
0.43
0.59
0.017
0.023
M
5.08
5.33
0.200
0.210
N
0.38
0.64
0.015
0.025
P
3.05
3.30
0.120
0.130
0.05 pF*
0.05 pF
Cp
Co
+
=
*Case Parasitics
Cp
Rm
Lm
Cm
-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
)
Typical Dimension:
0.010 to 0.047 inch
(0.25 to 1.20 mm)
(4 Places)
PDF 
ZIP