NTE1785
Integrated Circuit
TV IF Amp
w
/Demod and AFC
(For PNP Tuners)
Description:
The NTE1785 is an IF amplifier and demodulator circuit in a 16Lead DIP type package designed for
use in color and black and white television receivers using PNP tuners.
Features:
D
GainControlled WideBand Amplifier Providing Complete IF Gain
D
Synchronous Demodulator
D
White Spot Inverter
D
Video Preamplifier with Noise Protection
D
AFC Circuit which can be Switched ON/OFF by a DC Level (e.g. During Tuning)
D
AGC Circuit with Noise Gating
D
Tuner AGC Output (PNP Tuners)
D
VCR Switch which Switches Off the Video Output (e.g. For Insertion of a VCR Playback Signal)
Absolute Maximum Ratings:
Supply Voltage, V
1113
13.2V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tuner AGC Voltage, V
413
12V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Total Power Dissipation, P
tot
900mW
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Ambient Temperature Range, T
A
25
to +60
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range, T
stg
55
to +125
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Characteristics: (T
A
= +25
C, V
1113
= 12V, f = 38.9MHz unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Supply Voltage Range
V
1113
10.2
12.0
13.2
V
IF Input Voltage for Onset of AGC (RMS Value)
V
116(rms)
100
150
V
Differential Input Impedance
|Z
116
|
In parallel with 2pF
2
k
ZeroSignal Output Level
V
1213
Note 1
6
0.3
V
Top Sync Output Level
V
1213
2.9
3.07
3.2
V
IF Voltage Gain Control Range
G
V
64
dB
Bandwidth of Video Amplifier
B
3dB
6
MHz
Note 1. Socalled "Projected Zero Point", e.g. with switched demodulator.
Electrical Characteristics (Cont'd): (T
A
= +25
C, V
1113
= 12V, f = 38.9MHz unless otherwise
specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
SignaltoNoise Ratio
S/N
V
i
= 10mV, Note 2
58
dB
Differential Gain
dG
4
10
%
Differential Phase
2
10
deg.
Intermodulation, Blue
1.1MHz, Note 3
46
60
dB
Intermodulation, Yellow
46
50
dB
Intermodulation
3.3MHz, Note 4
46
54
dB
Carrier Signal at Video Output
4
30
mV
2
nd
Harmonic of Carrier at Video Output
20
30
mV
White Spot Inverter Threshold Level
6.6
V
White Spot Insertion Level
4.7
V
Noise Inverter Threshold Level
1.8
V
Noise Insertion Level
3.8
V
External Video Switch (VCR) Switched Off
V
1413
1.1
V
Tuner AGC Output Current Range
I
4
0
10
mA
Tuner AGC Output Voltage
V
413
I
4
= 10mA
0.3
V
Tuner AGC Output Leakage Current
I
4
V
1413
= 11V, V
413
= 12V
15
A
Maximum AFC Output Voltge Swing
V
513
10
11
V
Detuning for AFC Output Voltage Swing
f
of 10V
100
200
kHz
AFC ZeroSignal Output Voltage
(Minumum Gain)
V
513
4
6
8
V
AFC Switches ON
V
613
3.2
V
AFC Switches OFF
V
613
1.5
V
Note 2. S/N = V
O
blacktowhite/V
n(rms)
at B = 5MHz.
Note 3. 20 log (V
O
at 4.4MHz/V
O
at 1.1MHz) + 3.6dB.
Note 4. 20 log (V
O
at 4.4MHz/V
O
at 3.3MHz)
V
CC
Pin Connection Diagram
AFC Output
AFC Tank (Amp)
AFC Tank (Sync)
AFC Switch Input
AGC Output
GND
AGC Delay Input
AFC Tank (Amp)
AFC Tank (Sync)
Video Output
AGC Filter
IF Input
Coupling Cap
IF Input
1
2
3
4
5
6
7
8
16
15
14
13
Coupling Cap
12
11
10
9
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