WJCE6353SL9G5882170 INTEL [Intel Corporation], WJCE6353SL9G5882170 Datasheet - Page 24

• Manufacturer Part Number: WJCE6353SL9G5882170
• Description: Nordig Unified DVB-T COFDM Terrestrial Demodulator for PC-TV and Hand-held Digital TV (DTV)
• Manufacturer: INTEL [Intel Corporation]

4.4.1.3
To calculate the power dissipated in a crystal the following equation can be used.
Equation 3 -
Pc = power dissipated in crystal at resonant frequency (W)
Vpp = maximum peak to peak output swing of amplifier is 1.8 V for all CVDD
Zin = crystal network impedance (see Equation 2)
4.4.1.4
Using the loop gain limits (5 < A < 25), the maximum and minimum values for C1 and C2 can be calculated with
Equation 4 below.
Equation 4 -
Note: Equation 4 was derived from Equation 1 and Equation 2 using the premise that C1 = C2.
Within these limits, any value for C1 and C2 can now be selected. Normally C1 and C2 are chosen such that the
resulting crystal load capacitance C
(standard values for C
Equation 5 -
C
capacitance (including any socket used) and the printed circuit board’s track-to-track capacitance.
C
If some frequency pulling can be tolerated, a crystal load capacitance different from the crystal manufacturer’s
recommended C
tolerances on frequency stability. Smaller values of C
Care must however be taken that C
altogether. It is also possible to quote C
resonate, under the specified load conditions, at the desired frequency.
Finally the power dissipation in the crystal must be checked. If Pc is too high C1 and C2 must be reduced. If this is
not feasible C2 alone may be reduced. Unbalancing C1 and C2 will, however, require checking if the loop gain
condition is still satisfied. This must be done using Equation 1.
Note:
par12
par12
=
≈ 2pF.
2 >
parasitic capacitance between the XTI and XTO pins. It consists of the IC package’s pin-to-pin
Calculating Crystal Power Dissipation
Capacitor Values
C
C
- C
2
1
P
C
L
> 0.5
c
in
L
may be acceptable. Larger values of C
=
=
= C
L
8.Z
C
V
C
are 15 pF, 20 pF and 30 pF). The crystal will then operate very near its specified frequency.
pp
out
out
out
in
2
=
+ C
. C
in
in
+ C
L
g
A
L
m
does not fall outside the crystal pulling range or the circuit may fail to start up
par12
(see Equation 5) is close to the crystal manufacturers recommended C
L
-
to the crystal manufacturer who can then cut a crystal to order which will
R
2
f
-
Z
1
o
.
Intel Corporation
(2.π.f)
CE6353
L
24
tend to reduce startup time and crystal power dissipation.
1
2
.ESR when: C
L
tend to reduce the influence of circuit variations and
1
= C
2
= C
out
- C
par
Data Sheet
L