la7688b Sanyo Semiconductor Corporation, la7688b Datasheet - Page 9

• Manufacturer Part Number: la7688b
• Description: Pal/ntsc Color Television-use Single-chip Lsi
• Manufacturer: Sanyo Semiconductor Corporation

Continued from preceding page.
Frequency characteristics
Differential gain
Differential phase
No-signal AFT voltage
Maximum AFT voltage
Minimum AFT voltage
AFT detection sensitivity
APC pull-in range (U)
APC pull-in range (L)
VCO1 maximum variable
range
Parameter
fc
DG
DP
V 7
V 7 H
V 7 L
Sf
f PU
f PL
∆fU
∆fL
Symbol
TPO-8
TPO-8
TPO-8
TPO-7
TPO-7
TPO-7
TPO-7
TPO-8
TPO-8
TPO-8
point
Test
SG2,
fp = 38.9MHz,
cw, 80dBµ
SG1,
fc = 38.8MHz to
25MHz, cw
66dBµ
SG1,
fp = 38.9MHz,
staircase wave
AM = 87.5% MOD
80dBµ
Same as above
No-signal
SG1,
fp = 38.9MHz
±1MHz, cw,
80dBµ
Same as above
SG1
fp = 38.9MHz,
±1MHz, cw,
80dBµ
SG5
fp = 38.9MHz
5MHz cw,
50dB
Same as above
No-signal
symbol
Input
LA7688B
Mix the SG1 signal and SG2 signal and
input the mixed signal to VIF IN. Set the
SG1 frequency at 38.8MHz and using
an oscilloscope adjust the external
voltage at TPZ-46 so that the output
level at TP0-8 becomes 3V.
And then lower the SG1 frequency until
the output level at TP0-8 becomes
0.35Vp-p. Measure the frequency at
that moment.
fc = 38.9-f [MHz]
Measure the level at TP0-8 using a
vector scope.
Same as above
Measure the level at TP0-7 using a DC
digital voltmeter.
Connect a DC digital voltmeter to
TO0-7 and vary the SG frequency
±1MHz tomeasure a maximum voltage.
Connect a DC digital voltmeter to
TO0-7 and vary the SG frequency
±1MHz to measure a minimum voltage.
Connect a DC digital voltmeter to
TO0-7 and vary the SG frequency
±1MHz to measure frequency deviation
∆f when the voltage changes from 2V
to 7V.
Sf =
Connect an oscilloscope to TP0-8 and
set the SG5 frequency at a frequency
higher than 38.9MHz to unlock the PLL.
(The PLL is assumed to be unlocked
when a beat signal appears at TO0-8.)
When the SG5 frequency is lowered,
the PLL is unlocked again.
Measure the frequency at that moment
and assign the measured frequency to
f PU . For f PL , set the SG5 frequency at
a frequency lower than 38.9MHz and
make measurements in the
Same as above
Connect a spectrum analyzer to TO0-8
and check to see that the VCO
oscillation frequency is 9MHz. And then
apply DC voltage to TPZ-4A and vary it.
Assign the frequency max. at TO0-8 to
fU max. and the frequency min. at
TP0-8 to fL min.
∆fU = fUmax-38.9MHz
∆fL = 38.9MHz-fLmin
5000
∆
f
(
kHz
(
Test method
mV
)
)
[mV/kHz]
Continued on next page.
VR center
VR center
VR center
VR center
VR center
VR center
VR center
VR center
VR center
VR center
TPO-2
Applied voltage (V)
No.0077-9/20
Variable
TPZ-46
Open
Open
Open
Open
Open
Open
Open
7.8V
7.8V