NTE748
Integrated Circuit
TV Sound Circuit
Description:
The NTE748 is an integrated circuit in a 14Lead DIP type pacjage designed for IF limiting, detection,
audio preamplifier and driver for the sound portion of a TV receiver.
Features:
D
Excellent Limiting with 80
V(rms) Input Signal typ
D
Large OutputVoltage Swingto 3.5V(rms) typ
D
High IF Voltage Gain65dB typ
D
Zener PowerSupply Regulation Builtin
D
ShortCircuit Protection
D
A Coincidence Discriminator that Requires Only One RLC Phase Shift Network
D
Preamplifier to Drive a Single ExternalTransistor ClassA Audio Output Stage
Absolute Maximum Ratings: (T
A
= +25
C unless otherwise specified)
Power Supply Voltage, V+
+16V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Voltage, V
in
0.7V
(rms)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Dissipation (Package Limitation), P
D
625mW
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Derate above +25
C
5.0mW/
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Temperature Range, T
A
0
to +75
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range, T
stg
65
to +150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Characteristics: (V+ = 12V, T
A
= +25
C, f = 4.5MHz, Deviation =
25kHz unless
otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Input Voltage
V
L
3dB Limiting
80
160
V
rms
AM Rejection
AMR
V
in
= 20mV
rms
,
AM = 30%,
V
OFM
: f = 4.5MHz,
Deviation =
25kHz, Q
L
= 24
45
dB
AMR = 20 log,
Note 1
V
OAM
: f = 5.5MHz,
Deviation =
50kHz, Q
L
= 30
45
dB
Total Harmonic Distortion
THD
Q
L
= 24, 7.5kHz Deviation, Note 1
1.0
%
Maximum Undistorted Audio
Output Voltage (Pin10)
V
o(max)
Audio Gain Adjusted Externally, Q = 24, Note 1
3.5
V
rms
Electrical Characteristics (Cont'd): (V+ = 12V, T
A
= +25
C, f = 4.5MHz, Deviation =
25kHz
unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Recovered Audio (Pin2)
V
A
f = 4.5MHz, Deviation =
25kHz, Q
L
= 24, Note 1
0.35
0.50
V
rms
f = 5.5MHz, Deviation =
50kHz, Q
L
= 30, Note 1
0.80
V
rms
Audio Preamplifier
A
VP
Open Loop Gain
25
dB
IF Voltage Gain
A
VIF
65
dB
Parallel Input Resistance
R
in
9.0
k
Parallel Input Capacitance
C
in
6.0
pF
Nominal Zener Voltage
V
Reg
I
Z
= 5mA
11.6
V
Power Supply Current
I
D
I
Z
= 5mA
31
mA
Power Dissipation
P
D
I
Z
= 5mA
300
375
mW
Note 1. Q
L
is loaded circuit Q.
V
CC
Pin Connection Diagram
IF Output
Quadrature Network
1
2
3
4
Bypass
Audio Output
Bypass
IF Input
5
Bypass
6
Bypass
7
GND
14
13
12
11
Test Point
Quadrature Bypass
10
Preamp Output
9
Preamp Input
8
.600 (15.24)
1
7
14
8
.300
(7.62)
.200 (5.08)
Max
.100 (2.45)
.099 (2.5) Min
.785 (19.95)
Max
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