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©2008 by RF Monolithics, Inc. RO2073A-6 - 1/7/10
Electri cal Characteristics
Characteristic Sym Notes Minimum Typical Maximum Units
Center Frequency (+25 °C) Absolute Frequency fC2,3,4,5 314.950 315.050 MHz
Tolerance from 315.000 MHz ∆fC±50 kHz
Insertion Loss IL 2,5,6 1.3 2.2 dB
Quality Factor Unloaded Q QU5,6,7 15,300
50 Ω Loaded Q QL2,100
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≤10 ppm/yr
DC Insulation Resistance between Any Two Terminals 5 1.0 MΩ
RF Equivalent RLC Model Motional Resistance RM5, 7, 9 16 26 Ω
Motional Inductance LM127.450 µH
Motional Capacitance CM2.00299 fF
Shunt Static Capacitance CO5, 6, 9 2.0 2.3 2.6 pF
Test Fixture Shunt Inductance LTEST 2, 7 110 nH
Lid Symbolization (in addition to Lot and/or Dat e Codes) 164
• Ideal for 315.0 MHz Automotive-Keyless-Entry Transmitters
• Very Low Series Resistance
• Quartz Stability
• Surface-Mount Ceramic Case with 21 mm2 Footprint
• Complies with Directive 2002/95/EC (RoHS)
The RO2073A-6 is a true one-port, surface-acoustic-wave (SAW) resonator in a surface-mount, ceramic
case. It provides reliable, fundamental-mode, quartz fr equency stabilization of fixed-frequency transmitters
operating at 315.0 MHz. This SAW is 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
CW RF Power Dissipation (See: Typical Test Circuit) +0 dBm
DC voltage Between Terminals ±30 VDC
Case Tem perature -40 to +85 °C
Soldering Tem perature (10 seconds / 5 cycles max.) 260 °C
315.0 MHz
SAW
Resonator
RO2073A-6
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 resonator in the 50 Ω test system (VSWR ≤ 1.2:1). The shunt
inductance, LTEST, is tuned for parallel resonance with CO at fC. Typically, fOSCILLATOR or fTRANSMITTER is approximately equal to the resonator fC.
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 government approval, which is the responsibility of the equipment
manufacturer.
5. Unless noted otherwise, case temperature TC=+25°C±2°C.
6. The design, manufacturing process, and specifications of this device are subject to change without notice.
7. Derived mathem atically from one or more of the following directly measured parameters: fC, IL, 3 dB bandwidth, fC versus TC, and CO.
8. Turnover temperature, TO, is the temperature of maximum (or tur nover) frequency, fO. The nominal frequency at any case temperature, TC, may be
calculated from: f = fO[1 - FTC (TO-TC)2]. Typically oscillator TO is approximately equal to the specified resonator TO.
9. This equivalent RLC model approximates resonator performance near the resonant 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 parasitic capacitance with "NC” pads unconnected. Case parasitic capacitance is approximately 0.05 pF. Transducer parallel capacitance
can by calculated as: CP≈CO-0.05pF.
SM-2 Case
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©2008 by RF Monolithics, Inc. RO2073A-6 - 1/7/10
Electrical Con nections
The SAW resonator is bidirectional and may be
installed with either orientation. T he 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 the circuit.
Typical Test Circuit
The test circuit inductor, LTEST, is tuned to resonate with the static
capacitance, CO, at FC.
Typical Application Circuits
Equivalent LC Model
Temperature Characteristics
The curve shown on the right
accounts for resonator
contribution only and does not
include LC component
temperature contributions.
Typical Circuit Board
Land Pattern
The circuit board land pattern shown below is one possible design. The
optimum land pattern is dependent on the circuit board assembly proces s
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
minimize 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
Ω
Network Analyzer Network Analyzer
To 50
Ω
ELECTRICAL TEST
+9VDC
47
RF Bypass
L1
(Antenna)
C1
C2
200k
Ω
Modulation
Input
ROXXXXA
Bottom View
470
Typical Low-Power T ransmitter Application
RF Bypass
L1
C1
C2
ROXXXXA
Bottom View
Typical Local Os ci l la tor A ppl ic at ion
+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 1.70 2.29 0.067 0.090
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 Pa rasitics
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-foo
)/f(ppm)
Typical Dim ension:
0.010 to 0.047 inch
(0.25 to 1.20 mm)
(4 Places)
