SPECIFICATIONS
TYPICAL APPLICATION
FOR A PIERCE OSCILLATOR
Specifications are typical at 25
O
C unless otherwise noted.
Specifications are subject to change without notice.
Parameters
Fundamental
Overtone
Frequency, (kHz)
Motional Resistance R
1
(kΩ)
Motional Capacitance C
1
(fF)
Quality Factor Q (k)
Shunt Capacitance C
0
(pF)
Load Capacitance (pF)*
Turning Point (
o
C)*
Standard Calibration Tolerance**
Glass Lid:
Ceramic Lid:
Drive Level
30 ppm
(0.003%)
+
_
+
_
+
_
32.768
50
2.3
40
1.1
9
25
100
18
1.07
85
0.7
8
10
200
2.4
2.2
140
1.2
5
29
The CX4 family of surface mount crystals are ideal for
small, high density, battery operated portable products. The
CX4 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 50 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 CX4 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
100 ppm
(0.01%)
1000 ppm
(0.1%)
+
_
1000 ppm
(0.1%)
10000 ppm
(1.0%)
100 ppm
(0.01%)
+
_
+
_
0.5
µW
MAX
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
5 ppm
Shock, survival
Vibration, survival
Operating Temp. Range
5,000 g peak, 0.3 ms, 1/2 sine
20 g RMS, 10-2,000 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 C to +125 C
260
O
C for 20 sec.
O
O
(1)
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
1
+
Where f
S
C
1
C
0
C
1
2(C
0
+ C
L
)
Storage Temp. Range
Max Process Temperature
* Other values available
** Tighter tolerances available
[
]
(2)
= Series resonant frequency of the crystal
= Motional Capacitance
= Shunt Capacitance
TERMINATIONS
CONVENTIONAL CMOS
PIERCE OSCILLATOR CIRCUIT
Designation
SM1
SM2
SM3
CX4VSM
Termination
Gold Plated
Solder Plated
Solder Dipped
- Tray Pack
- 16mm tape, 7” or 13” reels
(Reference tape and reel data sheet 10109)
R
f
BUFFER
OSC
Freq (f
O
)
PACKAGING OPTIONS
AMPLIFIER
R
A
HOW TO ORDER CX4VSM CRYSTALS
CX4V
S
C
C = Ceramic Lid
Blank = Glass Lid
“S” if special or
custom design.
Blank if standard
SM1
32.768K , 100
Frequency
K = kHz
Calibration
Tolerance
@25
O
C
(in ppm)
/
I
C
G
SM1 = Gold Plated
SM2 = Solder Plated
SM3 = Solder Dipped
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
CX4
XTAL
C
D
10103 - Rev C
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 ]
