NTE842
Integrated Circuit
Television Video IF Amplifier,
Sync Separator, and AGC Processor
Description:
The NTE842 is a monolithic silicon integrated circuit in a 16Lead DIP type package designed to per-
form IF amplification, tuner AGC, and composite syncseparation functions in color or monochrome
TV receivers.
PIN diodes are used in the IF amplifiers for gain control, resulting in increased dynamic range and
better signaltonoise ratio.
Features:
D
HighGain WideBand IF Amplifiers
D
SampleandHold Keyed AGC
D
Composite Sync Separator with Noise Immunity
D
Fast AGC using PIN Diodes
D
Gain Reduction with Excellent Stability
D
Internal Varactor Pole Shift at Max Gain
Absolute Maximum Ratings:
DC Supply Voltage, V
CC
Between Pin11 and Pin3, Pin13
14V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Between 24K connected to Pin6 and Pin3, Pin13
25V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Supply Current, I
C
At Pin1 + Pin2 + Pin11 + Pin14 at Max. Gain
60mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
At Pin (Open Collector)
2mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Device Dissipation (T
A
+55
C), P
D
750mW
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Derate Above +55
C
7.9mW/
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Ambient Temperature Range, T
opr
40
to +85
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range, T
stg
65
to +150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead Temperature (During Soldering, 1/16" from case, 10sec max), T
L
+265
C
. . . . . . . . . . . . . . . . .
Electrical Characteristics: (T
A
= +25
C, +12V Supply)
Parameter
Test Conditions
Min
Typ
Max
Unit
Operating Supply Current
Note 1, I
1
+ I
2
+ I
11
+ I
14
40
60
mA
Supply Current
Note 2, I
1
+ I
2
+ I
11
+ I
14
15
20.5
30
mA
Initial Alignment
Note 3, Fixture Tune Voltage
0
8
15
V
Bandwidth 45.75MHz Response
Note 4
55
70
85
%
Skew (Pole Shift)
Note 5
35
60
85
%
Maximum Gain
Note 6
80
dB
AGC Gain Reduction
Note 16
80
dB
Sensitivity
Note 6
1.5
3
V
AGC Delay 1
Notes 7, 9
0
0.75
1
mA
AGC Delay 2
Notes, 8, 9
0
100
150
A
Noise
Note 10
9
11
mV
(rms)
Picture/Noise
Note 11
55
57
dB
Sync Output
1
Note 12
4.5
5
6
V
pp
2
4.5
5
6
IF AGC
A @
50mV
Note 13
6V
pp
Ref
B @
5mV
95
110
%
C @ 100mV
90
105
Bar (100 IRE) To Sync
Note 14
2
2.5
3
Ratio
Sync Tip
Note 15
1.4
1.8
2.2
V
Input Impedance
Note 1
1K
Note 1. No signal, AGC bias = GND (maximum gain).
Note 2. No signal, AGC bias = +10V (minimum gain).
Note 3. Adjust sweep generator for 50mV(rms) across an external 50
termination and sweep width
of 10MHz centered at 44MHz. Apply sweep signal (without 50
termination) to testfixture
input. Apply positive voltage (0V to 10V) to AGC bias input on fixture and adjust for a peak
response (44MHz) of 3V above GND while adjusting fixture tune voltage so that the re-
sponse at 42.17MHz and 45.75MHz are equal. This corresponds to a 5 to 8V peaktopeak
response curve on an oscilloscope. Measure the fixture bandwidth tune supply voltage.
Note 4. Retain tune voltage and AGC bias voltage from previous test. Measure response at
45.75MHz with respect to peak response (44MHz)
Note 5. Retain tune voltage. Reduce amplitude of sweep signal 34dB (1mV(rms) across 50
). Ad-
just AGC bias votlage so that the response at 45.75MHz is 3V above GND. Measure re-
sponse at 42.17MHz with respect to 45.75MHz.
Note 6. Retain tune voltage. Remove sweep signal. Apply +10V to AGC bias input. Measure video
output, V
OH
. (The voltage will depend on the individual unit of NTE842 used in the test circuit
and will be between 8 and 11V.) Remove +10V at AGC bias input, and ground the AGC bias
input. Apply a 200
V signal at 45.75MHz (as measured across an external 50
termination),
and measure the change in the video output voltage with respect to V
OH
. Note that the actual
sensitivity in a TV receiver can be higher because the test fixture includes a 5.2dB attenua-
tor.
Note 7. Retain tune voltage. With AGC bias open and video input switch closed, apply a 15mV(rms)
signal (as measured across an external 50
termination) at 45.75MHz. As the AGC delay
current is varied from 0 to 1mA, the reverse tuner output voltage should go from high to low,
and forward tuner output from low to high.
Note 8. Same as Note 7, except increase input signal to 60mV(rms). As the delay current is varied
from 0 to 150
A, the reverse tuner output voltage should go from high to low and forward
tuner output from low to high.
Note 9. The reverse tuner AGC output is an open collector. A 12K
resistor may be connected to
a +12V supply or a 24K
resistor to a +24V supply. The output high voltage will be within
1V of the supply voltage.
Note10. Apply a 45.75MHz, 50mV(rms) signal (as measured across an external 50
termination) to
the fixture input. Apply a positive DC voltage to the AGC bias input and close the video input
switch. Adjust the AGC bias for a 2V reading at the video output. Measure the AC rms noise.
Note 11. Apply a 100 IRE barmodulated IF signal to the fixture IF input. Modulation should be set
at 87.5%. Close the video input switch. Using an external 75
to 50
matching pad and
50
step attenuators, adjust the modulated IF signal to a 50mV equivalent (141.5mV
pp
sig-
nal on a wideband oscilloscope). Apply a key pulse to fixture input. Measure amplitude
of 100 IRE bar signal (black level to white level) at video output. (S + N)
N = 20 Log
10
(Bar
Noise).
Note12. Signal conditions same as Note 11. Measure amplitude of sync output. Repeat test with IF
input attenuated 20dB (14.5mV
pp
). Output at Pin12 is 9V
pp
to 12V
pp
.
Note13. A. Signal conditions same as Note 11. Measure amplitude of 100 IRE bar.
B. Repeat test with IF input attenuated 20dB. B% = 100 x Test 13B
Test 13A.
C. Repeat test with IF input increased 6dB (283 mV
pp
). C% = 100 x Test 13C
Test 13A.
Note14. Same signal and conditions as Note 11. Measure ratio of 100 IRE bar signal to sync signal
of composite video output. Repeat test with input IF signal increased 6dB.
Note15. The sync tip to ground voltage is equivalent to the keyed AGC threshold. The test signal and
conditions are the same as Note 11. Measure the sync tip to ground voltage at the video
output.
Note16. A typical application circuit includes a tuner having at least 20dB AGC gain reduction.
2
nd
Amp Output
2
nd
Amp Input
1
st
Amp Input
1
st
Amp Output
Pin Connection Diagram
Sync Filter
Sync Output
Forward AGC Output
Input GND
1
2
3
4
Max Gain Bias
5
AGC Filter
6
Reverse AGC Output
7
16
15
14
13
AGC Delay
Substrate GND
12
11
(+) 12V Supply
10
Video Input
8
Key Pulse Input
9
.700 (17.78)
.100 (2.54)
1
8
16
9
.200 (5.08)
Max
.870 (22.0)
Max
.260 (6.6)
Max
.099 (2.5) Min
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