SPECIFICATIONS
TYPICAL APPLICATION
FOR A PIERCE OSCILLATOR
Specifications are typical at 25
O
C unless otherwise noted.
Specifications are subject to change without notice.
Frequency Range
Functional Mode
Calibration Tolerance*
800 kHz - 1.35 MHz
Extensional
500 ppm (0.05%)
1000 ppm (0.1%)
+
_
10000 ppm (1.0%)
7 pF
+
_
+
_
Load Capacitance
Motional Resistance (R
1
)
Motional Capacitance (C
1
)
Quality Factor (Q)
Shunt Capacitance (C
0
)
Drive Level
Turning Point (T
0
)**
5 kΩ MAX
1.2 fF
150 k
1.0 pF
3
µW
MAX.
35
O
C
The low profile CX miniature surface mount crystal is ideal
for small, high density, battery operated portable products.
The CX crystal designed in a Pierce oscillator (single
inverter) circuit provides very low current consumption and
high stability. A conventional CMOS Pierce oscillator circuit
is shown below. The crystal is effectively inductive and in a
PI-network circuit with C
D
and C
G
provides the additional
phase shift necessary to sustain oscillation. The oscillation
frequency (f
0
) is 15 to 150 ppm above the crystal’s series
resonant frequency (f
S
).
Drive Level
R
A
is used to limit the crystal’s drive level by forming a
voltage divider between R
A
and C
D
. R
A
also stabilizes the
oscillator against changes in the amplifiers output
resistance (R
0
). R
A
should be increased for higher voltage
operation.
Load Capacitance
The CX crystal calibration tolerance is influenced by the
effective circuit capacitances, specified as the load
capacitance (C
L
). C
L
is approximately equal to:
C
L =
C
D
x C
G
C
D
+ C
G
+
C
S
Temperature Coefficient (k) -0.035 ppm/
O
C
2
Note: Frequency f at temperature T is related to frequency f
0
at turning point temperature T
0
by
:
f-f
0
2
=
k(T-T
0
)
f
0
Aging, first year
Shock, survival
Vibration, survival
Operating Temp. Range
5 ppm MAX
1000 g peak, 0.3 ms,1/2 sine
10 g RMS, 20-1,000 Hz random
-10
O
C to +70
O
C (Commercial)
-40
O
C to +85
O
C (Industrial)
-55
O
C to +125
O
C (Military)
-55
O
C to +125
O
C
260
O
C for 20 sec.
(1)
Storage Temp. Range
Max Process Temperature
* Tighter tolerances available.
** Other values available.
NOTE: C
D
and C
G
include stray layout to ground and C
S
is the stray shunt capacitance between the crystal
terminal. In practice, the effective value of C
L
will be less
than that calculated from C
D
, C
G
and C
S
values because
of the effect of the amplifier output resistance. C
S
should
be minimized.
The oscillation frequency (f
0
) is approximately equal to:
f
0
=
f
S
PACKAGING OPTIONS
C
[
1 +
2(C
1
0
+ C
L
)
]
(2)
CX3SM
- Tray Pack
- Tape and Reel
(Reference tape and reel data sheet 10109)
Where f
S
C
1
C
0
= Series resonant frequency of the crystal
= Motional Capacitance
= Shunt Capacitance
TERMINATIONS
CONVENTIONAL CMOS
PIERCE OSCILLATOR CIRCUIT
Designation
SM1
SM2
SM3
Termination
Gold Plated
Solder Plated
Solder Dipped
R
f
BUFFER
OSC
Freq (f
O
)
HOW TO ORDER CX3SM CRYSTALS
CX3
S
C
SM1
1.0M,
500
Calibration
Tolerance
@ 25
O
C
(in ppm)
Frequency
K = kHz
M = MHz
AMPLIFIER
R
A
/
M
“S” if special or
custom design.
Blank if Std.
SM1 = Gold Plated
SM2 = Solder Plated
SM3 = Solder Dipped
Blank = Glass Lid
C = Ceramic Lid
Operating Temp. Range:
C = -10
O
C to +70
O
C
I = -40
O
C to +85
O
C
M = -55
O
C to +125
O
C
S = Customer Specified
C
G
CX3
XTAL
C
D
10123 - Rev B
S
YS
ERT
T
E
M
C
IFIC
T
A
N
IO
RSG Electronic Components GmbH - Sprendlinger Landstr. 115 - 63069 Offenbach - Germany - www.rsg-electronic.de
IS
O
90
01
RSG [ RSG ELECTRONIC COMPONENTS GMBH ]
