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.
RO2156A_RO2156A-1_RO2156A-2 _012202
Electrical Characteristics
Characteristic
Sym
Notes
Minimum
Typical
Maximum
Units
Frequency at +25C Nominal Frequency RO2156A
f
C
2,3,4,5
868.875
869.025
MHz
RO2156A-1
868.875
869.175
RO2156A-2
868.850
869.050
Tolerance from 868.95 MHz RO2156A
f
C
75
kHz
RO2156A-1
-75
+225
RO2156A-2
100
Insertion Loss
IL
2,5,6
1.1
2.0
dB
Quality Factor
Unloaded Q
Q
U
5,6,7
38,997
50
Loaded Q
Q
L
4,000
Temperature Stability
Turnover Temperature
T
O
6,7,8
10
25
40
C
Turnover Frequency
f
O
f
C
kHz
Frequency Temperature Coefficient
FTC
0.032
ppm/C
2
Frequency Aging
Absolute Value during the First Year
|fA|
1
<10
ppm/yr
DC Insulation Resistance between Any Two Terminals
5
1.0
M
RF Equivalent RLC Model
Motional Resistance
R
M
5, 6, 7, 9
11.4295
Motional Inductance
L
M
81.637
H
Motional Capacitance
C
M
0.41
fF
Shunt Static Capacitance
C
O
5, 6, 7, 9
2.9
pF
Test Fixture Shunt Inductance
L
TEST
2, 7
11.5679
nH
Lid Symbolization (in Addition to Lot and/ or Date Code)
197
Ideal for European 868.95 MHz Transmitters
Very Low Series Resistance
Quartz Stability
Surface-Mount Ceramic Case with 21 mm
2
Footprint
Complies with Directive 2002/95/EC (RoHS)
The RO2156A 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 operat-
ing at 868.95 MHz. This SAW is designed specifically for remote-control and wireless security transmitters
operating under ETSI-ETS 300 220 in Europe and under FTZ 17 TR 2100 in Germany.
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 max.)
260
C
868.95 MHz
SAW
Resonator
RO2156A
RO2156A-1
RO2156A-2
CAUTION: Electrostatic Sensitive Device. Observe precautions for handling.
Notes:
1.
Lifetime (10 year) frequency aging.
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
.
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 gov-
ernment approval, which is the responsibility of the equipment manufacturer.
5.
Unless noted otherwise, case temperature T
C
= +25C2C for all specifica-
tions.
6.
The design, manufacturing process, and specifications of this device are sub-
ject 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 cal-
culated from: f = f
O
[1 - FTC (T
O
-T
C
)
2
].
9.
This equivalent RLC model approximates resonator performance near the
resonant 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 parasitic capacitance with "NC" pads unconnected. Case parasitic
capacitance is approximately 0.05pF. Transducer parallel capacitance can be
calculated as: C
P
C
-
0.05 pF.
SM-2 Case
868.95 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.
RO2156A_RO2156A-1_RO2156A-2 _012202
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)
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