844

NTE844
Integrated Circuit
Single Chip TV Chroma/Luminance Processor
Description:
The NTE844 is an integrated circuit in a 28–Lead DIP type package and contains all the required circuits functions between the video detector and the picture tube RGB driver stages of a color television
receiver. The NTE844 decodes the chrominance signals and then produces three different color signals that are internally combined with the luminance to develop the RGB signals. The picture saturation, hue and brightness DC controls are externally adjustable. The AFPC, ACC, Dynamic flesh control, Beam limiting and Gate black level (Brightness)control are servo loops used to stabilize the RGB
output and reduce frequent manual adjustment. The automatic beam limiter circuit reduces picture
contrast and brightness to prevent excessive drive output at the picture tube.
Features:
D All chroma processing and demodulating circuitry on a single chip.
D Phase–locked subcarrier regeneration utilizing sample–and–hold techniques.
D Supplementary ACC with overload detector
D Linear DC controls for chroma gain and tint
D Dynamic “flesh correction”
D Balanced chroma demodulators with low output impedance for direct coupling
D Internal RF filtering
D Few external components
D Automatic beam limiter
D Chroma luminance tracking picture control
Absolute Maximum Ratings:
DC Supply Voltage Between Pin23 and Pin8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.0V
Device Dissipation (Up to TA = +55°C), PD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.27W
Derate Above TA = +55°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.3mW/°C
Operating Ambient Temperature Range, Topr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40° to +85°C
Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65° to +150°C
Lead Temperature (During Soldering, 1/16” from case, 10sec max), TL . . . . . . . . . . . . . . . . . +265°C
Typical Performance Characteristics:
Function
Typical Data
Nominal Supply
11.2V
Nominal Dissipation
500mW
Oscillator Stability
Supply Variation 10–14 V
5Hz
Variation with Temperature
(∆T = +50°C)
AFPC Characteristics
DC Loop Gain
Pull–In Range
ACC Characteristic
100% Chroma Input Level
3dB Point
25Hz
33Hz/Degree
±500Hz
250mVp–p on Red Bar
at 20% Nominal Input Level
Hue–Control Range
100°
Saturation–Control Range
40dB Min
Demodulator Characteristics:
Relative
Amplitude
Angle
R–Y
1.0
93°
B–Y
1.2
2°
G–Y
0.3
258°
Bandwidth (Chroma)
900kHz
Flesh Control
Primary Control in the +1 Half–Plane
Chroma Overload Control
Two Levels
Picture Control
40dB
Brightness Control
Black Level Clamped on 3V to 5V Level
Beam Limiting
On Picture and Brightness Controls
Luma Bandwidth
5MHz Min
Sandcastle Input
1.2V to 2.3V
Blanking
> 3.3V
Maximum Linear Output
R
Burst gate
5V
G
3V
B
3.7V
Pin Connection Diagram
Chroma Output 1
28 Beam Limiter
Chroma Control 2
Chroma Input 3
27 Luminance
26 Picture Control
Overload Filter 4
ACC, Killer Filter 5
25 Low Pass Filter
24 Bright Control
ACC, Killer Filter 6
Sandcastle Pulse 7
23 VCC
22 Blue
GND 8
APC Filter 9
21 Red
20 Green
APC Filter 10
19 Q Carrier Input
OSC Input 90° 11
OSC Input 180° 12
OSC Output 13
Tint Control 14
18 I Carrier Input
17 Demodulator Chroma Input
16 Overload, Flesh Disable
15 Carrier Output
14
1
15
28
1.469 (37.32) Max
.540
(13.7)
.250
(6.35)
.100 (2.54)
1.300 (33.02)
.122
(3.1)
Min
.600 (15.24)