la7688b Sanyo Semiconductor Corporation, la7688b Datasheet - Page 18

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

Continued from preceding page.
Vertical output voltage
Vertical external trigger load
resistance
Vertical automatic sync stop
voltage
Horizontal AFC gate
release voltage
Vertical output pulse start
V CC voltage
Horizontal free-running
frequency deviation
Dependence of horizontal
free-running
frequency on V CC
Horizontal pull-in range
Horizontal output pulse start
V CC voltage
AFC2 FBP peak value
Parameter
V OUT H
V OUT M
V OUT L
R TR
V SAS
V GS
S VV
∆ fH
∆ fHV CC
fHPULL
S HV
FBPH
FBPM
FBPL
Symbol
Z-20B
Z-20B
O-20C
I-20A
Z-22
Z-22
Z-20A
Z-20B
V CC
O-25
O-25
O-25
I-14A
O-25
I CC
Z-26B
point
Test
I-14A :
Horizontal ⋅
vertical sync
signal
I-14A :
Horizontal
sync signal
I-14A :
Horizontal ⋅
vertical sync
signal
I-14A :
Horizontal
sync signal
I-14A :
No signal
(open)
I-14A :
No signal
(open)
I-14A :
No signal
(open)
I-14A :
Horizontal
sync signal
I-14A :
No signal
(open)
I-14A :
Horizontal
sync signal
signal
Input
LA7688B
Measure the voltage for each vertical output at
Z-20B.
Turn on SW20 and set V,VR to a maximum and
then decrease slowly until the vertical output period
becomes 225H.
Turn off SW20 and measure the resistance
between O-20C and GND.
Use the vertical output at Z-20B to synchronize an
oscilloscope and monitor the output waveform at
Z-22.
Connect a DC power supply to I-20A and raise the
voltage slowly until the output waveform becomes
larger.
Measure the voltage at I-20A at that moment.
Connect a DC power supply to I-20A and set it at
0V. Monitor the AFC1 waveform at Z-22 and raise
the supply voltage at Z-20A slowly until the AFC1
waveform for the vertical sync's equivalent pulse
period changes.
Measure the voltage at Z-20A at that moment.
Raise V CC (pins 40, 44, and 45) from 0V slowly
until a pulse signal appears in the vertical output at
Z-20B. Measure V CC at that moment.
Connect a counter to O-25 (horizontal output) to
measure the horizontal free-running frequency.
Calculate the deviation from 15.680kHz.
Connect a DC power supply to I CC (horizontal pin
24 V CC ) and set it at 6.0V. And then measure the
horizontal output frequency at TP14 and calculate
the deviation from the horizontal free-running
frequency.
Monitor the horizontal sync signal and the
horizontal output at O-25 using an oscilloscope
and vary the horizontal sync signal frequency to
measure the pull-in range.
Connect a DC power supply to I CC (horizontal pin
24 V CC ) and raise it from 0V slowly until a pulse
signal appears in the horizontal output at O-25.
Measure the Icc pin voltage at that moment.
Measure the FBP peak value at Z-26B.
V OUT H
0V
0V
FBPL
FBPM
Test method
V OUT L
FBPH
V OUT M
Continued on next page.
SW20
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
↓
No.0077-18/20
SW25
B
B
B
B
B
B
B
B
B