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©2008 by RF Monolithics, Inc. RO2103A - 3/24/08
Electri cal Characteristics
Characteristic Sym Notes Minimum Typical Maximum Units
Frequency (+25 °C) Nominal Frequency fC2, 3, 4, 5 417.925 418.075 MHz
Tolerance from 418.000 MHz ΔfC±75 kHz
Insertion Loss IL 2, 5, 6 1.0 2.0 dB
Quality Factor Unloaded Q QU5, 6, 7 16,100
50 Ω Loaded Q QL1,700
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 M otional Resistance RM5, 6, 7, 9 12 26 Ω
Motional Inductance LM74.8223 µH
Motional Capacitance CM1.93705 fF
Transducer Static Capacitance CO5, 6, 9 1.6 1.9 2.2 pF
Test Fixture Shunt Inductance LTEST 2, 7 80 nH
Lid Symbolization 106
• Ideal for 418 MHz Transmitters in the U.K. and U.S.
• Very Low Series Resistance
• Quartz Stability
• Surface-Mount, Ceramic Case with 21 mm2 Footprint
• Complies with Directive 2002/95/EC (RoHS)
The RO2103A is a true one-port, surface-acoustic-wave (SAW) resonator in a surface-mount, ceramic case.
It provides reliable, fundam ental-mode, quartz frequency stabilization of fixed-frequency transmitters
operating at 418.0 MHz. This SAW is designed for remote-control and wireless security transmitters operating
in the United Kingdom under DTI MPT 1340 and in the USA under FCC Part 15.
Absolute Maximum Ratings
Rating Value Units
CW RF Power Dissipation (See Ty pic a l Test Circuit) +0 dBm
DC Voltage Between Terminals (Observe ESD Precautions) ±30 VDC
Case Tem perature -40 to +85 °C
Soldering Tem peratur e (10 seconds / 5 cycles max.) 260 °C
418.0 MHz
SAW
Resonator
RO2103A
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 tem-
peratures above +65°C. T ypically, 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. T ypic ally, fOSCILLATOR or fTRANSMITTER is approximately
equal to the resonator fC.
3. One or more of the following United States patent s 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 mathematically 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
turnover) 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 capacit ance
meter. The measurement includes parasitic capacitance with "NC”
pads unconnected. Case paras itic 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. RO2103A - 3/24/08
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 res onate with the static
capacitance, CO, a t 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 pa ttern
shown below is one possible design. The optimum 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 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 o f 40 to
70 microinches electroless gold on 60-350 micorinches electroless nickel.
NC NC
Terminal
Terminal
From 50
Ω
Network Analyzer Network Analyz er
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 cillator Appl ication
+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
Δ
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)
