NTE821
Integrated Circuit
TV Chroma Demodulator
Description:
Specifically designed to match advances in color picture tube phosphors, the NTE821 is a monolithic
silicon integrated circuit in a 14Lead DIP type package and consists of three output amplifiers, a
new resistor matrix, two doublebalanced chroma demodulators, and a very stable bias circuit. When
used with the NTE714 subcarrier regeneration system and the NTE715 chroma amplifier, this device
completes the typical threeblock chroma system. Alternatively, the NTE821 chroma demodulator
can be used with the NTE738 chroma processor to form a complete twoblock chroma system.
The output amplifiers are specifically designed to meet the low impedance, shortcircuit protected
driving requirements of highlevel color output amplifiers. Internal ripple filter capacitors greatly re-
duce the highfrequency components of demodulation and thereby extend the output voltage swing
capability of the output stages and at the same time eliminates the need for external output filtering
components.
Features:
D
Output ShortCircuit Protection
D
Excellent Subcarrier Rejection
D
600mV Maximum Offset Voltage
D
2mV/
C Typical Temperature Stability
D
Good Chroma Sensitivity
Absolute Maximum Ratings: (T
A
= +25
C unless otherwise specified)
Operating Ambient Temperature Range, T
opr
40
to +85
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range, T
stg
65
to +150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Voltage and Current Ratings (T
A
= +25
C)
See Table
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current in mA
Current in mA
Pin #
Voltage Range in Volts
Input
Output
Pin #
Voltage Range in Volts
Input
Output
1
No Connection
8
0 to +27
Note 2
1.0
2
No Connection
9
0 to +20
1.0
Note 1
3
0 to +5.0
10
No Connection
4
0 to +5.0
11
0 to +20
1.0
Note 1
5
No Connection
12
No Connection
6
0 to +12
13
0 to +20
1.0
Note 1
7
0 to +12
14
Reference
1.0
Note 2
Note 1. Maximum continuous current output is 20mA and is limited by package power dissipation.
Short circuit current is typically 50mA.
Note 2. Limited by package power dissipation.
Electrical Characteristics: (T
A
= +25
C, V
CC
= 24V, R
L
= 3.3k
, Reference Input Voltage = 1V
PP
unless otherwise specified)
Parameter
Test Pin
Test Conditions
Min
Typ
Max
Unit
Static Characteristics
Quiescent Output Voltage
9, 11, 13
13.0
14.3
16.0
V
Quiescent Input Current
8
R
L
=
, Chroma and Reference
Voltage = 0
6.0
mA
Chroma and Reference Voltage = 0
16.5
19.0
25.5
mA
Reference Input Voltage
6, 7
6.6
V
Chroma Input Voltage
3, 4
3.5
V
Differential Output Voltage
9, 11, 13 Note 3
200
600
mV
Output Temperature Coefficient
9, 11, 13 No Output Differential Voltage, Note 3
2.0
mV/
C
Dynamic Characteristics
Detector Output Voltage (BY)
13
Note 4
8
13
V
PP
Chroma Input Voltage
3
BY Output = 5V
PP
, Note 5
300
700
mV
PP
Detector Output Voltage (GY)
9
Adjust BY Output to 5V
PP
, Note 6
1.4
1.75
2.1
V
PP
Detector Output Voltage (RY)
11
Adjust BY Output to 5V
PP
, Note 6
4.3
4.65
5.0
V
PP
Relative Output Phase (BY to RY)
1311
BY Output = 5V
PP
85
90
95
deg
Relative Output Phase (BY to GY)
139
BY Output = 5V
PP
236
244
252
deg
Demodulator Unbalanced Voltage
9, 11, 13 No Chroma Input Voltage and Normal
Reference Signal Input Voltage
250
500
mV
PP
Residual Carrier and Harmonics
9, 11, 13 With Input Signal Voltage, Normal Refer-
ence Signal Voltage and BY = 5V
PP
1.5
V
PP
Reference Input Resistance
6, 7
Chroma Input = 0
2.0
k
Reference Input Capacitance
6, 7
Chroma Input = 0
6.0
pF
Chroma Input Resistance
3, 4
1.0
k
Chroma Input Capacitance
3, 4
2.0
pF
Note 3. With chroma input signal voltage = 0 and normal reference input signal voltage (1V
PP
), all
output voltages will be within specified limits and will not differ from each other by greater
than 0.6V.
Note 4. With normal reference input signal voltage, adjust chroma input signal voltage to 1.2V
PP
.
Note 5. With normal reference input signal voltage, adjust chroma input signal voltage until the BY
output voltage = 5V
PP
. The chroma input voltage at this point should be equal to or less than
0.7V
PP
.
Note 6. With normal reference input signal voltage, adjust the chroma input signal until the BY out-
put voltage = 5V
PP
. At this point, the RY and GY voltages will fall within the specified limits.
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