![](http://datasheet.mmic.net.cn/100000/CX-1C-SM1FREQ-B-M-_datasheet_3058096/CX-1C-SM1FREQ-B-M-_2.png)
Typical Pierce Oscillator Application
The low profile CX miniature surface-mount crystal is ideal for small,
battery operated portable products. The CX crystal design in a Pierce
oscillator (single inverter) circuit has a very low current consumption
with high stability. A conventional HCMOS Pierce oscillator circuit is
shown below. The crystal is effectively inductive and in a Pi network
with C and C which provides the additional phase-shift necessary
to sustain oscillation. The oscillation frequency (f ) is 15ppm to
150ppm above the crystal’s series resonant frequency (F ).
R is used to limit the crystal’s drive level by forming a voltage
divider between R andC.R also stabilizes the oscillator against
changes in the amplifiers output resistance (R ). R should be
increased for higher voltage operation.
The CX crystal calibration tolerance is influenced by the effective
circuit capacitances, specified as the load capacitance (C .) C is
approximately equal to:
12
0
S
A
A1
A
0A
LL
Drive Level
Load Capacitance
Circuit Design
CX-1-SM - Tray Pack (Standard)
- 16mm tape, 178mm or 330mm reels (Optional)
per EIA 481
Packaging
Terminations
Designation
SM1
Gold Plated
SM2
Nickel, Silver Plated
SM3
Nickel, Solder Plated and Solder Dipped
Termination
C =
Cx C
C+ C
2
1
LS
C
+
NOTE: C and C include stray layout capacitance to ground. C is
the stray shunt capacitance between the crystal terminals. In
practice, the effective valus of C will be less than that calculated
fromC,C,and CS values due to the effect of the amplifier output
resistance. C should be minimized.
The oscillation frequency (f ) is approximately equal to:
12
S
L
12
S
0
Where F = Series resonant frequency of the crystal
C = Motional Capacitance
C = Shunt Capacitance
S
1
0
f =
C1
0 fS
2(C+ C)
0L
1+
Conventional HCMOS Pierce Oscillator Circuit
CX-1
Buffer
Amplifier
Osc.
Freq. (Fo)
C
C
C5
RB
R)
Order Code
CX-1
“S” if special
or custom design
Blank if standard
Frequency
SM1
SM2
SM3
Calibration
Tolerance*
@ 25°C
(A)
(B)
(C)
1.0MHz
-SM1
*For other
calibrations
insert value
in ppm
Temperature
Range:
C = Commercial
I = Industrial
M = Military
S = Specify
(A/I)
Blank = Glass Lid
C = Ceramic Lid
CX-1-SM
530kHz to 2.1MHz
MINIATURE SMD CRYSTAL
CX-1-SM
530kHz to 2.1MHz
MINIATURE SMD CRYSTAL
+44(0)1460 230000
+44(0)1460 230001
sales@euroquartz.co.uk
www.euroquartz.co.uk
Telephone:
Fax:
Email:
Web:
EUROQUARTZ
CX MINIATURE CRYSTALS
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