SANYO LA7642N Datasheet
Overview
The LA7642N integrates the chrominance circuit for a
SECAM format TV in a single 16-pin DIP (300 mil)
package and provides an adjustment-free discriminator
circuit. In combination with the Sanyo LA7687, LA7688,
this IC can implement a multi-format color TV signalprocessing system.
Features
• Adjustment-free discriminator circuit
• On-chip bell filter
Package Dimensions
unit: mm
3006B-DIP16
Monolithic Linear IC
Ordering number : EN5693
73097HA(OT) No. 5693-1/6
SANYO: DIP16
[LA7642N]
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
SECAM Format Color TV Chrominance Circuit
LA7642N
Parameter Symbol Conditions Ratings Unit
Maximum supply voltage V
CC
max 9V
Allowable power dissipation Pd max Ta ≤ 65°C 400 mW
Operating temperature Topr –10 to +65 °C
Storage temperature Tstg –55 to +125 °C
Specifications
Maximum Ratings at Ta = 25°C
Parameter Symbol Conditions Ratings Unit
Recommended operating voltage V
CC
7.8 V
Operating voltage range V
CC
op 7.0 to 8.5 V
Operating Conditions at Ta = 25°C
Parameter Symbol Conditions
Ratings
Unit
min typ max
[Circuit Voltage and Current]
Chrominance system. Measure the current
Circuit current I
CC
flowing into pin 15; With no signal applied to 28 35 42 mA
pin 14.
[Filter Block]
Input impedance
The pin 14 input impedance. For reference
15 kΩ
only (design value)
Operating Characteristics at Ta = 25°C, VCC= 7.8 V, with pin 13 pulled up to VCCthrough a 20-kΩ resistor
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No. 5693-2/6
LA7642N
Parameter Symbol Conditions
Ratings
Unit
min typ max
Referenced to 4.286 MHz. For reference only.
EQU = off.
Input a 20 mV p-p, f = 4.286 MHz CW signal
Bell filter frequency characteristics
BEL4.086
to pin 14 and, measure the pin 16 output
–9 –6 –3 dB
4.086 MHz (f = 4.286 MHz). Next, input a CW of
20 mV p-p, f = 4.086 MHz and measure the
pin 16 output (f = 4.086 MHz) and calculate
the frequency characteristics.
Referenced to 4.286 MHz. For reference only.
EQU = off.
Input a 20 mV p-p, f = 4.286 MHz CW signal
Bell filter frequency characteristics
BEL4.486
to pin 14 and, measure the pin 16 output
–5 –2 –0.5 dB
4.486 MHz (f = 4.286 MHz). Next, input a CW of
20 mV p-p, f = 4.486 MHz and measure the
pin 16 output (f = 4.486 MHz) and calculate
the frequency characteristics.
Referenced to 4.286 MHz. For reference only.
EQU = on.
Input a 20 mV p-p, f = 4.286 MHz CW signal
EQU frequency characteristics
EQU4.086
to pin 14 and, measure the pin 16 output
–10.5 –7.5 –4.5 dB
4.086 MHz (f = 4.286 MHz). Next, input a CW of
20 mV p-p, f = 4.086 MHz and measure the
pin 16 output (f = 4.086 MHz) and calculate
the frequency characteristics.
Referenced to 4.286 MHz. For reference only.
EQU = on.
Input a 20 mV p-p, f = 4.286 MHz CW signal
EQU frequency characteristics
EQU4.486
to pin 14 and measure the pin 16 output
–3 0 +3 dB
4.486 MHz (f = 4.286 MHz). Next, input a CW of
20 mV p-p, f = 4.486 MHz and measure the
pin 16 output (f = 4.486 MHz) and calculate
the frequency characteristics.
Referenced to 4.35 MHz. For reference only.
EQU = off.
Input a 20 mV p-p CW signal to pin 14 and
Bell filter frequency deviation from BELF0 modify the frequency of that signal. Measure –50 0 +50 kHz
center frequency the deviation from 4.35 MHz of the frequency
(the center frequency) for which the pin 16
output is maximized.
Referenced to 4.35 MHz. For reference only.
Bell filter gain difference at f0 ±500 kHz BELdG
EQU = off.
–1 0 +1 dB
Measure the gain at the BELF0 ±500 kHz,
and calculate the difference.
[Chrominance Block]
Let 0 dB = 200 mV p-p. Input a color bar
signal to pin 14 and gradually lower the input
Killer operating point KILL signal level. Measure the input level at the –42 –36 –33 dB
point the pin 13 DC voltage falls below 1/2*
V
CC
.
The pin 7 B-Y amplitude for a color bar signal.
B-Y output amplitude VBY
Let 0 dB = 200 mV p-p. Input a color bar
0.60 0.75 0.90 Vp-p
signal (0 dB) to pin 14, and measure the B-Y
amplitude at pin 7.
The pin 6 R-Y amplitude for a color bar signal.
R-Y output amplitude VRY
Let 0 dB = 200 mV p-p. Input a color bar
0.74 0.92 1.10 Vp-p
signal (0 dB) to pin 14, and measure the R-Y
amplitude at pin 6.
VRY/VBY. Calculate the ratio of the values
R-Y/B-Y output ratio RATRB measured above. 1.1 1.23 1.35
RATRB = VRY/VBY
Input a color bar signal (0 dB) to pin 14. In the
pin 7 (B-Y) output waveform measure the
amplitude of the blue (+230 kHz) and yellow
B-Y linearity LINBY
(–230 kHz) components (A) and measure the
85 100 115 %
amplitude of the blue green (+78 kHz) and
red (–78 kHz) components (B). Calculate the
value of LINBY from the following formula.
LINBY = (A/B)
× (156/460) × 100 (%)
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