CA3126 Datasheet, PDF (8/9 Pages) Intersil Corporation – TV Chroma Processor

CA3126
curve of the typical static phase error as a function of the free-
running oscillator frequency is shown in Figure 2. It should be
noted that the slope of the curve determines the DC gain of the
phase-locked loop, i.e., 40Hz per degree.
6 ^{TA = 25oC}
4
2
0
-2
-4
-300 -200 -100
0
100 200 300 400
OSCILLATOR FREE-RUNNING FREQUENCY
(DEVIATION IN Hz FROM 3.579545MHz)
FIGURE 2. STATIC PHASE ERROR
Thermal Considerations
The circuit of the CA3126 is thermally compensated to achieve
the optimal operating characteristics over the normal operating
temperature range of TV receivers. Figures 3 and 4 show the
oscillator and chroma-output amplitudes and phases as a func-
tion of temperature (Terminals 8 and 15), respectively.
Both the oscillator and chroma-output amplitudes and
phases are measured relative to the chroma-input phase.
The performance of the oscillator free-running frequency as
a function of temperature is shown in Figure 5. All the tem-
perature plots are characteristic of the test circuit with the
indicated component types and values given.
110 ^{CHROMA INPUT = 0.25VP-P, 3.58MHz CW SIGNAL}
100
PHASE
0
140
15
CHROMA INPUT = 0.25V_P-P,
3.58MHz CW SIGNAL
130
10
120
5
PHASE
110
0
100
AMPLITUDE
-5
90
-10
80
-15
-50
-25
0
25
50
75
100
TEMPERATURE (^oC)
FIGURE 4. AMPLITUDE AND PHASE VARIATIONS OF
CHROMA OUTPUT vs TEMPERATURE
CHROMA INPUT = 0V_P-P
100
50
0
-50
-100
-150
-50 -25
0
25
50
75
TEMPERATURE (^oC)
100 125
FIGURE 5. VARIATION OF OSCILLATOR FREE RUNNING
FREQUENCY vs TEMPERATURE
90
AMPLITUDE
80
-5
70
60
-50
-25
0
25
50
TEMPERATURE (^oC)
-10
75
100
FIGURE 3. AMPLITUDE AND PHASE VARIATIONS OF
OSCILLATOR OUTPUT vs TEMPERATURE
8-40