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Electrical Characteristics
Characteristic Sym Notes Minimum Typical Maximum Units
Frequency, +25 °C RO3156A fC
2,3,4,5
868.750 869.150 MHzRO3156A-1 868.800 869.100
RO3156A-2 868.850 869.050
Tolerance from 868.95 MHz RO3156A
∆fC
±200 kHzRO3156A-1 ±150
RO3156A-2 ±100
Insertion Loss IL 2,5,6 1.2 2.0 dB
Quality Factor Unloaded Q QU5,6,7 6200
50 Ω Loaded Q QL850
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 14.5 Ω
Motional Inductance LM18.0 µH
Motional Capacitance CM2.0 fF
Shunt Static Capacitance CO5, 6, 9 2.1 pF
Test Fixture Shunt Inductance LTEST 2, 7 15.8 nH
Lid Symbolization RO3156A: 714, RO3156A-1: 923, RO3156A-2 828, //YWWS
• Ideal for European 868.95 MHz Transmitters
• Very Low Series Resistance
• Quartz Stability
• Surface-mount Ceramic Case
• Complies with Directive 2002/95/EC (RoHS)
The RO3156A 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 specifically for remote-control and wireless security
transmitters operating under ETSI EN 300 220 in Europe.
Absolute Maximum Ratings
Rating 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 maximum 260 °C
868.95 MHz
SAW
Resonator
RO3156A
RO3156A-1
RO3156A-2
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
Notes:
1. Freque n c y ag in g i s the ch an g e 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.
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 shun t
induc tance, 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 ± 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
calcula ted fro m: 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.
SM5035-4
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© 2009-2011 by RF Monolithics, Inc. RO3156A - 7/5/11
Electrical Connections
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, a t FC.
Typical Application Circuits
Equivalent Model
Temperature Characteristics
The curve shown on the right
accounts for resonator
contribution only and does not
include LC component
temperature contributions.
Case
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
POWE R 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 5.00 5.13 0.191 0.196 0.201
B 3.37 3.50 3.63 0.132 0.137 0.142
C 1.45 1.53 1.60 0.057 0.060 0.062
D 1.35 1.43 1.50 0.040 0.057 0.059
E 0.67 0.80 0.93 0.026 0.031 0.036
F 0.37 0.50 0.63 0.014 0.019 0.024
G 1.07 1.20 1.33 0.042 0.047 0.052
H - 1.04 - - 0.041 -
I - 1.46 - - 0.058 -
J - 0.50 - - 0.019 -
K - 1.05 - - 0.041 -
L - 1.44 - - 0.057 -
M - 0.71 - - 0.028 -
0.05 pF*
0.05 pF
Cp
Co+
=
*Case Parasitics
Cp
Rm
Lm C m
-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)
A
B C
D
E ( 3 x )
F ( 4 x )
G ( 1 x )
T o p V i e w S i d e V i e w B o t t o m V i e w
1
2
3
4
H
I
H H
J
J
K
L
MM
PCB Land Pattern
Top View
