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©2008 by RF Monolithics, Inc. RO3156A-3 - 9/24/08
Electrical Characteristics
Characteristic Sym Notes Minimum Typical Maximum Units
Frequency (+25 °C) Nominal Frequency fC2,3,4,5 868.875 869.025 MHz
Tolerance from 868.95 MHz ∆fC±75 kHz
Insertion Loss IL 2,5,6 1.2 2.0 dB
Quality Factor Unloaded Q QU5,6,7 7500
50 Ω Loaded Q QL700
Temperature Stability Turnover Temperature TO6,7,8 10 25 40 °C
Turnover Frequency fOfCkHz
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, 6, 7, 9 10.2 Ω
Motional Inductance LM14.0 µH
Motional Capacitance CM2.0 fF
Shunt Static Capacitance CO5, 6, 9 2.1 pF
Test Fixture Shunt Inductance LTEST 2, 7 14.3 nH
Lid Symbolization (in addition to Lot and/or Date Codes) 808 // YWWS
• Ideal for European 868.95 MHz Transmitters
• Very Low Series Resistance
• Quartz Stability
• Surface-Mount Ceramic Case with 21 mm2 Footprint
• Complies with Directive 2002/95/EC (RoHS)
The RO3156A-3 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 868.95 MHz. This SAW is designed s pecifically for remote-cont rol and wireless security trans-
mitters operating under ETSI-ETS 300 220 in Europe and under FTZ 17 TR 2100 in Germany.
Absolute Maximum RatingsRating Value Units
CW RF Power Dissipation +5 dBm
DC Voltage Between Terminals ±30 VDC
Case Temperature -40 to +85 °C
Soldering Temperature (10 seconds / 5 cycles max.) 260 °C
868.95 MHz
SAW
Resonator
RO3156A-3
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 subse-
quent years.
2. The center frequency, fC, is measured at the minimum insertion loss point, ILMIN,
wit h the resonator in the 50 Ω test system (VSWR ≤ 1.2:1). The shunt induc-
tance, LTEST, is tuned for parallel resonance with CO at fC. Typically, fOSCILLA-
TOR or fTRANSMITTER is approximately equal to the resonator fC.
3. One or more of the following United S tates 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 TC= +25°C±2°C.
6. The design, manufacturing process, and specifications of this device are subject
to change witho ut 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. T urnover temperature, TO, is the temperature of maximum (or turnover) fre-
quency, fO. The nominal frequency at any case temperature, TC, may be calcu-
lated from: f = fO[1 - FTC (TO-TC)2]. Typic ally oscillator TO is approximately
equal to the specified resonator TO.
9. This equivalent RLC model approximates resonator performance near the reso-
nant frequency and is provided for reference only. The capacitance CO is the
static (nonmotional) capacitance between the two terminals measured at low fre-
quency (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.
SM5035-4
868.95 MHz SAW Resonator
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©2008 by RF Monolith ics, Inc. RO3156A-3 - 9/24/08
Electrical Con nections
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 c ircuit inductor, LTEST, is tuned to resonate with the static capaci-
tan ce , C O, at FC.
Typical Application Circuits
Equivalent LC Model
Temperature Characteri stics
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 manuf acturer. 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
Terminal
Terminal
Case Ground
Case Ground
ELECTRICAL TEST
From 50 Ω
Network Analyzer To 50 Ω
Networ k A nalyzer
50 Ω Source
at FCREFLECTED
INCIDENT
P
P
Low-Loss
Matching
Network to
50 Ω
Terminal
Terminal
NC NC
POWER T EST
CW RF Power Dissipation = INCIDENT - REFLECTED
P P
C1
C2
L1
(Antenna)
+9VDC
47
RF Bypass
Modulation
Input
Typical Low-Power Transmitter Application
RO3XXXA
Bottom View 470
200kΩ
C1
C2
L1
Output
+VDC
RF Bypass
+VDC
Typical Local Oscillator Applications
RO3XXXA
Bottom View
Dimensions Millimeters Inches
Min Nom Max Min Nom Max
A 4.87 5.0 5.13 .191 .196 .201
B 3.37 3.5 3.63 .132 .137 .142
C 1.451.531.60.057.060.062
D 1.351.431.50.040.057.059
E .67 .80 .93 .026 .031 .036
F .37 .50 .63 .014 .019 .024
G 1.071.201.33.042.047.052
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-foo
)/f(ppm)
Typical Dimensio n:
0.010 t o 0.0 47 inch
(0.25 to 1. 20 mm)
(4 Places)
A
B C
D
E
(3x)
F
(4x)
G
(1x
Top View Side View Bottom View
1
2
3
4
