
IDT / ICS VCXO-TO-LVCMOS OUTPUTS
9
ICS81006AK REV. B OCTOBER 8, 2008
ICS81006
VCXO-TO-6 LVCMOS OUTPUTS
APPLICATION INFORMATION
Oscillator
FIGURE 1: VCXO OSCILLATOR CIRCUIT
V
C
V
C
S1
C
L1
C
S2
C
L2
C
V
XTAL
VCXO (Internal)
Optional
Control Voltage
TABLE 5. EXAMPLE CRYSTAL PARAMETERS
l
o
b
m
y
Sr
e
t
e
m
a
r
a
Ps
n
o
i
t
i
d
n
o
C
t
s
e
Tm
u
m
i
n
i
Ml
a
c
i
p
y
Tm
u
m
i
x
a
Ms
t
i
n
U
f
N
y
c
n
e
u
q
e
r
F
l
a
n
i
m
o
N
4
.
9
1z
H
M
f
T
e
c
n
a
r
e
l
o
T
y
c
n
e
u
q
e
r
F
0
2
±m
p
f
S
y
t
il
i
b
a
t
S
y
c
n
e
u
q
e
r
F
0
2
±m
p
e
g
n
a
R
e
r
u
t
a
r
e
p
m
e
T
g
n
i
t
a
r
e
p
O
00
7C
°
C
L
e
c
n
a
t
i
c
a
p
a
C
d
a
o
L
2
1F
p
C
O
e
c
n
a
t
i
c
a
p
a
C
t
n
u
h
S
4F
p
C
,
0 C1
o
i
t
a
R
y
t
il
i
b
a
ll
u
P
0
2
20
4
2
R
S
Ee
c
n
a
t
s
i
s
e
R
s
e
i
r
e
S
t
n
e
l
a
v
i
u
q
E
0
2
l
e
v
e
L
e
v
i
r
D
1W
m
C
°
5
2
@
g
n
i
g
A
r
a
e
y
r
e
p
3
±m
p
n
o
i
t
a
r
e
p
O
f
o
e
d
o
M
l
a
t
n
e
m
a
d
n
u
F
VCXO CRYSTAL SELECTION
Choosing a crystal with the correct characteristics is one of the
most critical steps in using a Voltage Controlled Crystal Oscillator
(VCXO). The crystal parameters affect the tuning range and
V
C
Control voltage used to tune frequency
C
V
Varactor capacitance, varies due to the change in
control voltage
accuracy of a VCXO. Below are the key variables and an example
of using the crystal parameters to calculate the tuning range of
the VCXO.
C
L1, CL2
Load tuning capacitance used for fine tuning or
centering nominal frequency
C
S1, CS2
Stray Capacitance caused by pads, vias, and other
board parasitics