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NTE875
Integrated Circuit
Video IF Amplifier/PLL Detector System
Description:
The NTE875 is a complete video IF signal processing system on a single 28–Lead DIP type package.
This device contains a 5–stage gain–controlled IF amplifier, a PLL synchronous amplitude detector,
self–contained gated AGC, and a switchable AFC detector. The increased flexibility of the NTE875
makes it suitable for a wide variety of television applications where high quality video or sound carier
recovery is required. These include home receiver video IFs, cable and subscription TV decoders,
and parallel sound IF/intercarrier detector systems. Typical operating frequencies are 38.9MHz,
45.75MHz, 58.75MHz, and 61.25MHz.
Features:
D Low Differential Gain and Phase
D IF and Detector pin Compatible with NTE878 (Discontinued)
D Common–Base IF Inputs for SAW Filters
D True Synchronous Video Detector using PLL (Phase Lock Loop)
D Excellent Stability at High System Gains
D Noise–Average Gated AGC System
D Uncommitted AGC Comparator Input
D Internal AGC Gate Generator
D Superior Small–Signal Detector Linearity
D AFC Detector with Adjustable Output Bias
D 9MHz Video Bandwidth
D Reverse Tuner AGC Output
Absolute Maximum Ratings:
Power Supply Voltage, V
IF Supply Current, I
AGC Gate Voltage, V
Video Output Current, I
Phase Lock Loop (PLL) Filter Current, I
Detector Input Signal, ν
Power Dissipation, P
Thermal Resistance, Junction–to–Ambient, R
Junction Temperature, T
Operating Temperature Range, T
Storage Temperature Range, T
2
5
14
16
18
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DET
D
thJA
J
opr
stg
Lead Temperature (During Soldering, 10sec), T
15V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
60mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±5V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1V
rms
2W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
50°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
+125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0°C to +70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
–65°C to +150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
L
+260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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DC Electrical Characteristics: (TA = +25°C, VIF = ν
switches in position 0 (open) unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
= 0, VPH = 4V, V
DET
= 4V, and all
COMP
12V Supply Current I1 + I2V
IF Regulator Voltage V
5
IF Input Voltage V7, V8V
IF Decouple Offset V6 – V9V
IF Peaker Voltage (Max Gain) V3, V4V
IF Output Current I
1
IF Peaker Voltage (Min Gain) V3, V4V
Detector Input Voltage V
28
Limiter Tank Voltage V24, V25V
AFC Tank Voltage V23, V26V
VCO Tank Voltage V19, V20V
AGC Sync Threshold V
AGC Filter Leakage Current I
AGC Filter Charge Current I
AGC Filter Discharge Current I
RF AGC Leakage Current I
RF AGC Output Current I
17
13
13
13
11
11
= 6.7V, V
AGC
V
= 6.7V, SW4 Position 1 5.8 6.4 7.0 V
AGC
= 2V, SW2, 3, 4 Position 1 3.2 3.7 4.1 V
AGC
= 2V, SW2, 3, 4 Position 1 – 0 ±30 mV
AGC
= 2V, SW2, 3, 4 Position 1 2.3 3.0 3.6 V
AGC
V
= 9V, SW2, 3, 4 Position 1,
AGC
Measure V
= 9V, SW2, 3, 4 Position 1 5.5 6.2 – V
AGC
V
= 6.7V, SW1, 4 Position 1 4.3 4.9 5.5 V
AGC
= 6.7V, SW1, 4 Position 1 6.4 7.0 7.6 V
AGC
= 6.7V, SW1, 4 Position 1 4.3 4.9 5.5 V
AGC
= 6.7V, SW1, 4 Position 1 4.7 5.2 5.7 V
AGC
, I1 = (12 – V1)/50
1
SW1, 2 Position 1, Adjust V
= 0
I
13
= 6V 35 60 80 mA
COMP
3.1 5.5 7.8 mA
COMP
for
3.8 4.0 4.2 V
SW1, 2, 4 Position 1 – 0 ±5 µA
SW1, 2 Position 1, V
SW1, 2 Position 1, V
V
= 2V, All Switches Position 1,
AGC
Measure V
V
= 10V, All Switches Position 1,
AGC
Measure V
, I11 = (12 – V11)/6000
11
, I11 = (12 – V11)/6000
11
= 3.5V 1.6 2.2 2.8 mA
COMP
= 4.5V –0.45 –0.70 –0.90 mA
COMP
– 0 20 µA
1.5 1.8 – mA
Detector AC Set–Up Procedure: (SW1, 4 position 1, V
1. Apply ν
DET
= 10mV
, 45.75MHz CW at the detector input. Tune L1 for maximum AC signal
rms
at Pin25, measured with a 10x FET probe or through a 1pF capacitor to prevent loading of
the limiter tank.
2. Increase ν
to 60mV
DET
. Adjust L3 until the PLL locks, as indicated by a DC voltage at
rms
the video output Pin16.
3. With the detector locked, adjust L3 for 4V at Pin18.
4. Adjust V
for maximum detector efficiency by monitoring Pin16 for a minimum DC voltage.
PH
5. Adjust L2 for 3.0V at Pin27 (on sensitive slope of AFC curve).
AC Electrical Characteristics:
(TA = +25°C, Detector set–up as above, f = 45.75MHz,
V
= 6.7V, V
AGC
= 4V, and allswitches in position 0 (open)
COMP
unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
IF Amplifier Gain ν
V
for 15dB Gain Reduction SW2, 3, 4 Position 1, νIF = 2.8mV
AGC
V
for 45dB Gain Reduction SW2, 3, 4 Position 1, νIF = 89mV
AGC
OUT/νIFVAGC
= 2V, SW2, 3, 4 Position 1,
ν
= 500µV
IF
Adjust V
, Note 1
rms
for Same ν
AGC
Test
Adjust V
for Same ν
AGC
Test
AGC
= 0V)
OUT
OUT
as Gain
rms
as Gain
rms
25 35 – dB
,
4.2 4.6 5.0 V
,
5.1 5.5 6.1 V
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AC Electrical Characteristics (Cont’d): (TA = +25°C, Detector set–up as above, f = 45.75MHz,
V
= 6.7V, V
AGC
= 4V, and allswitches in position 0
COMP
(open) unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
Zero Carrier Level V
Detected Output Level ∆V
SW1, 2, 4 Position 1, ν
16
SW1, 2, 4 Position 1, ν
16
Measure Change in V
= 0 6.6 7.4 8.4 V
DET
= 60mV
DET
from Zero
16
rms
,
2.0 3.0 4.3 V
Carrier Test
Overload Output Voltage V
AFC Output Voltage (OFF) V
AFC Minimum Output Voltage V
SW1, 2, 4 Position 1, ν
16
SW1, 2, 4 Position 1, ν
27
SW1, 4 Position 1, ν
27
= 600mV
DET
= 0 2.8 3.0 3.2 V
DET
= 60mV
DET
rms
rms
,
– 2 3 V
– 0.5 1.0 V
46.75MHz
AFC Maximum Output Voltage V
SW1, 4 Position 1, ν
27
DET
= 60mV
rms
,
9 10 – V
44.75MHz
PLL Pull–In Range ∆f SW1, 4 POsition 1, ν
= 60mV
DET
rms
,
2 3 – MHz
Vary Frequency and Measure the
Difference between Lock Points
Note 1. The IF amplifier gain is specified with the IF output connected to a 50Ω measurement system
which results in a 25Ω loaded impedance. The gain in an actual application will typically be
26dB higher.
Pin Connection Diagram
IF Output
1
Detector Input
28
V
CC
IF Gain Adjust
IF Gain Adjust
RF AGC Output
RF AGC T akeover Adjust
AGC Gate Generator Time Constant
2
3
4
5IF Supply
6IF Decouple
7IF Input
8IF Input
9IF Decouple
10IF GND
11
12
13AGC Filter
14
AFC Output
27
AFC Tank
26
25 Limiter Tank
Limiter Tank
24
AFC Tank
23
Detector Phase Adjust
22
21 Substrate GND
20 VCO Tank
VCO Tank
19
18 PLL Filter
17 Input to AGC Comparator
16 Video Output
15
Supply Decouple
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14 1
15 28
1.469 (37.32) Max
.100 (2.54)
1.300 (33.02)
.250
(6.35)
.122
(3.1)
Min
.540
(13.7)
.600 (15.24)
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