TUA6039 Infineon Technologies Corporation, TUA6039 Datasheet - Page 8

• Manufacturer Part Number: TUA6039
• Description: Stationary - Mopll & Silicon Tuner
• Manufacturer: Infineon Technologies Corporation

Infineon Technologies’ bipolar process with a transit frequency (f
satisfy a low intrinsic F requirement of oscillator. The external applications of the oscillator should be
carefully designed not to degrade Q with regard to stable oscillation.
6. Calculate C68 ;
3
4
L(fm) is ratio of noise power in a 1-Hz bandwidth in units of dBc/Hz. fo is the frequency of oscillation.
fc is the flicker noise corner. F is the noise figure of oscillator. Ps is the carrier power. K is Boltzmann's
constant, 1.38x10
process, which is fundamentally a sampled system in digital implementations. Since the control voltage
directly modulates the frequency of the VCO, any AC components of tuning voltage results in a frequency
modulation of the oscillator. If these components are periodic, they produce fixed side-bands like
reference spurs. Because of the wide tuning range of the Half NIM, the tuning sensitivity can go up to
35MHz/V, so even a few milli-volts of noise on the tuning lines might generate noticeable spectral
interference.
The oscillator's output now has the benefits of phase locking such as improved stability and phase noise
and this is another crucial function of PLL. By determining a proper loop bandwidth, optimum phase noise
characteristics of the reference oscillator and the local oscillator can be utilized. For a given loop
bandwidth, a higher order filter provides more attenuation of out-of-band spectral components. However,
the higher the order, the more poles there are, making it more difficult to maintain the stability of the loop.
The loop bandwidth and loop filter components should be carefully selected to achieve optimal phase
noise and to reject reference spurs. Four extended modes of charge pump currents also must be
appropriately chosen and used for best phase noise performance of different frequency ranges. For this
tuner design DVB-T recommended Fref=166.667kHz is used for all loop filter calculations and
measurements.
determine the loop filter components.
1.
2.
3.
4.
5.
7.
.
.
1992, pp.385-491.
pp.179-194.
Hajimiri, A., & Lee, T.H., A genaral theory of phase noise in electrical oscillators, IEEE journal of solid-state circuits, Vol.33, No.2,
G.Vendelin, A.Pavio, U.Rohde, Microwave Circuit Design using Linear & Nonlinear Techniques, John Wiley & Sons, New York,
A 3
The critical role of loop filter is to remove the reference spurs produced by the phase detection
Define the basic synthesizer requirements ; oscillator frequency ranges, f
Bandwidth, Hz) with deep consideration of in-out band phase noise.
Identify Kvco(VCO sensitivity, Hz/V) and Icp(charge pump current, A).
Calculate F
Calculate N = f
Calculate natural frequency, F
Calculate R39, and its phase noise contribution. This completes the main part of the loop filter.
rd
order passive loop filer is chosen for the tuner design. The following are simplified procedures to
step
vco_max
-23
= f
J/K. T is Kelvin temperature. Q
vco_max
/ f
Application Notes Revision 3.0
L
(
ref,
- f
fm
vco_min,
to optimize for f
)
=
Fn
C
n
10
68
;
ζ
=
log
=
to optimize for f
= damping factor
2





N
π
1
2
I
×
×
2




cp
(



2 (
×
ζ
2
×
π
f
+
QLfm
BW
Application Engineering
vco_max
4
fo
K
×
×
1
vco
F
ζ
n



)
2 )
2
.
vco_max
+
Hz
1
L




is loaded Q factor.
Farad



7
fm
fc
+
1






FkT
Ps
T
) of 25 GHz to produce TUA6039-2 can








ref
, maximum frequency step, f
Communication Solutions
(2)
(3)
IFAP COM Tuner Systems
(1)
May 2007
BW
(Loop