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NTE849 Integrated Circuit TV Horizontal/Vertical Countdown Digital Sync System
Description: The NTE849 is an integrated circuit in a 14-Lead DIP type package designed for use in TV horizontal/ vetical countdown digital sync systems. In some video playback units, there are incorrect frequency relationships between horizontal and field frequencies. Automatic forced asynchronous mode eliminates jitter when equalizer pulses are correct, but these incorrect frequency relationships exist. Automatic standard mode occurs upon detection of nine or more equalizing pulses during a six-line- width vertical driving period after seven fields of coincidence between integrated vertical (IV) sync and internal counter output. Standard mode is retained for seven fields of missing or mutilated vertical sync pulses. If two or more noise pulses are detected at Pin12 during a 384-line active scan time, a noise detector reverts the system to standard mode at the next field of coincidence (without seven fields of coincidene delay). Thus, the unit stays in standard mode during tuner channel changes. An automatic mode-recognition system places the unit in standard mode for NTSC signals or into non-synchronous mode for non-standard sync signals. An external oscillator (NTE701) supplies an input to Pin9 that is 32 times the horizontal rate. An internal divide-by-16 counter converts this input (32fH) to 2fH for use elsewhere. This 32fH signal is further divided to fH, which is available at Pin11 to drive the horizontal deflection circuits. A divide-by-525 counter further divides the 2fH signal to generate the vertical ramp generator timing pulses and the vertical blanking pulse. A phasing circuit (part of the mode recognition and vertical regeneration circuits) insures that the 525 counter is reset in coincidence with the vertical sync. It does this by comparing the internally generated vertical pulse with an extrnal integrated vertical sync signal applied to Pin12. The automatic mode recognition circuit forces the NTE849 into the standard mode for NTSC signals or into the non- synchronous mode for non-standard sync signals such as video games. An input control signal (or no connection) at Pin8 places the NTE849 into non-synchronous operation. A phasing and timing logic circuit checks to see if the line counter is in sync with the IV signal at Pin12. Seven consecutive fields of in-phase coincidence with the IV signal are needed to achieve standard mode in unless two or more noise pulses are de-detected at input Pin12 during the active scan time. In this case, normal mode will be acquired in one field.
Description (Cont'd): In the standard divide-by-525 mode, the integrated vertical pulse is used only to provide coincidence with the 545 count (counter preset = 20, 545 - 20 = 525) in the phase detector circuit. The vertical ramp is timed by the output of the 525 counter. In standard mode, the NTE849 will maintain the divide- by-525 count for six fields of lost or mutilated sync. If the seventh field does not have the correct coincidence, the unit will switch to non-standard mode. In this mode, the vertical sync is derived from the integrated vertical pulse on a field-to-field basis. A noise immunity of 384 lines is provided. In the absence of sync pulses, the count will be 684 instead of 525 so that rapid vertical capture may be achieved when sync is restored. Non-satndard mode still may be selected by removing GND from Pin8. The vertical retrace signal is converted to a ramp signal if a capacitor is connected between Pin3 and GND. The ramp's slope corresponds to vertical size and is controlled by changing the input current to Pin2. The ramp is connected to the inverting input of a diffrence amplifier. The output of this amplifier, connectd to Pin6, is used to drive the vertical output stage. The non-inverting input of the difference amplifier is at Pin5. A voltage derived from yoke current may be applied to this pin for linearity improvement. The pulse width of the vertical blanking signal at Pin7 is 608 clocks wide in the synchronous mode, and is adjustable in width by changing the monostable RC network at Pin10 for the non-synchronous mode. The proportional voltage regulator output at Pin4 is about 43% of the supply voltage at Pin12. The maximum external load current is 20mA (Peak).
Features: D Automatic Forced Asynchronous Mode to Remove Jitter D Improved Low Voltage Start-Up Operation D Lower Zero-State Horizontal-Drive Pulse Output D Improved Symmetry for Horizontal-Drive Output D Improved Automatic Standard Operation D Noise Detector D Handles Standard NTSC and Non-Standard Signals D Automatic Mode Recognition
D D D D D D D D D D D D
Clock Input Vertical Ramp (Sawtooth) Generator Vertical Amplifier Vertical Blanking Generator Horizontal Drive Pulse Output Ratio-Voltage Regulator Inherent Interlace for NTSC Signals Vertical-Hold Control Eliminated Supply Voltage Range: 10.8V to 13.2V Rapid Pull-In Co-Channel Sync Lockout for NTSC Signals I2L Logic
Absolute Maximum Ratings: DC Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15V Device Dissipation (TA +70C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530mW Derate Linearily Above 70C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.7mW/C Operating Ambient Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to +70C Storage Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to +150C Lead Temperature (During Soldering, 1/16" from case, 10sec max) . . . . . . . . . . . . . . . . . . . . +265C
Electrical Characteristics: (TA = +25C, all switches open, test pin 2 & 14 = GND unless otherwise specified)
Parameter Amplifier Gain, V6 Horizontal Frequency Divider Ratio, fg / f11 Horizontal Pulse Width, Pin11 Test Conditions S2, S5, S6 Colsed, Note 1 Test pin 1 = 12V, 16 = 1VRMS at 1kHz S3, S7, S8 Closed, Note 7, Test pin 1 = 14.4V S3, S7, S8 Closed, Notes 9, 10, Test pin 1 = 8.4V S3, S7, S8 Closed, Notes 9, 10, 11, Test pin1 = 14.4V Asynchronous Non-Coincident Frequency Divide Ratio, fg / f3 Ramp Charge Pulse Width, Pin3 S3, S7, S8 Closed, Notes 9, 12, 13, 14, 15, Test pin 1 = 14.4V, 8 = 0.2V, 12 = 1.5V S3, S7, S8 Closed, Notes 13, 15, Test pin 1 = 14.4V, 8 = 0.2V, 12 = 1.5V Min 0.178 32 28 28 Max 3.16 32 34 34 Unit VRMS Ratio s s Ratio s Ratio Ratio Clocks Clocks
10944 10944 585 7872 8400 190 606 585 7872 8400 194 610
Asynchronous Coincident Noise Immunity, Notes 9, 12, 13, 15, 16, 17, Test pin 1 = 14.4V, Hold-Off Frequency Divide Ratio, f8 / f3 8 = 0.2V Synchronous Divider Ratio, fg / f3 Ramp Charge Pulse Width, Pin3 Vertical Blanking Pulse Width, Pin7 Mode Recognition Field Count Frequency Divide Ratio, fg / f3 Synchronous to Non-Synchronous S3, S7, S8 Closed, Notes 9, 13, 15, 18, 19, Test pin 1 = 14.4V, 8 = 0.2V, 12 = 1.5V S3, S7, S8 Closed, Notes 9, 10, 13, 15, 18, 20, Test pin 1 = 14.4V, 8 = 0.2V, 12 = 1.5V S3, S7, S8 Closed, Notes 9, 10, 13, 15, 18, 21, Test pin 1 = 14.4V, 8 = 0.2V, 12 = 1.5V S3, S7, S8 Closed, Notes 9, 13, 14, 15, 18, 22, Test pin 1 = 12.0V, 8 = 0.2V, 12 = 1.5V Initial Fields 9 Serrations First Field, 8 Serrations Second Field, 8 Serrations Third Field, 8 Serrations Fourth Field, 8 Serrations Fifth Field, 8 Serrations Sixth Field, 8 Serrations Seventh Field, 8 Serrations Mode Recognition Field Count Frequency Divide Ratio, fg / f3 Non-Synchronous to Synchronous S3, S7, S8 Closed, Notes 9, 13, 15, 18, 23, Test pin 1 = 12.0V, 8 = 0.2V First Field Second Field Third Field Fourth Field Fifth Field Sixth Field Seventh Field Eight Field Ninth Field Fast Standard-Mode Resynchronization S3, S7, S8 Closed, Notes 9, 13, 15, Test pin 1 = 12.0V, 8 = 0.2V
8400 8400 8400 8400 8400 8400 8400
8400 8400 8400 8400 8400 8400 8400
Ratio Ratio Ratio Ratio Ratio Ratio Ratio Ratio
10944 10944
8384 8384 8384 8384 8384 8384 8384 8400 8400
8384 8384 8384 8384 8384 8384 8384 8400 8400
Ratio Ratio Ratio Ratio Ratio Ratio Ratio Ratio Ratio
Static Characteristics:
(TA = +25C V+ = 12V, switches open, test pin 2, 8, 12, & 14 = GND unless otherwise specified)
Connect Test Pins as Shown Below Test Conditions S2 Closed, Note 1 1 12V 14.4V -20mA S2 Closed Notes 1, 4 Test pin 15 = 8V S2 Closed Notes 5, 6 S4 Closed, Note 1 S3 Closed, Note 1 S2 Closed, Note 1 S2 Closed, Note 1 Test pin 9 = GND, S2 Closed, Note 2 S2 Closed, Note 3 12V 12V 14.4 12V 12V 12V 12V 14.4V 14.4V 14.4V 12V 14.4V S2 Closed, Note 3, Test pin 8 = 4.5V S3 Closed, Note 1, Test pin 2 = 50A 12V 12V 12V S2 Closed, Note 4 12V 12V S2 Closed, Note 4, Test pin 12 = 2.3V S2 Closed, Note 4, Test pin 12 = 3.0V 12V 12V 4.5V 1.5V 2V 2V 2V 2V 3.0V 4.5V GND 4V 2V 2V 2V 2V 2V 2V 4V 0V GND GND GND GND GND 1mA -20mA -20mA 20mA 2.5 0.09 7.0 0 0.6 3.4 -0.15 10 -180 - 100 -25 1.0 45 -3 10 1 -0.1 01 5.0 0.5 8.1 0.12 1.4 5.1 0.15 35 -70 0.75 700 25 3.2 57 3 40 5 5.0 3.0 V V V V V V V mA A V A mA mA A A A mA A mA 3 4 -20mA 5 2V 2V 6 10 11 13 Min 4.9 5.8 Max 5.5 6.8 Unit V V
Parameter Ratio Regulator Voltage, V4 Load No Load Vertical Blanking Output, V7 Unblanked Blanked Horizontal Output Voltage, V11 High Low Vertical Output Voltage, V6 Off On Difference Voltage, V3 - V5 Supply Current, I1 Clock Current, I9: Low Voltage, V9
Composite Sync Input Current, I13 Sync High S2 Closed, Note 1 Sync Low Forced Asynchronous Current, I8 Ramp Current, I3 Ramp Current, I3 Async Time Constant Current, I10 Charge Discharge Vert Sync Input Current, I12 Normal Overdrive
Notes: Note 1. Note 2. Note 3. Note 4. Note 5. Note 6. Note 7. Note 8. Note 9. Note10. Note 11. Note12. Note13. Stop clock when Pin7 is high. Stop clock when Pin9 is low. Stop clock when Pin9 is high. Stop clock when Pin7 is low. Stop clock when Pin11 is high. Stop clock when Pin11 is low. Clock frequency = 600kHz, clock amplitude: low 0.45V, high 0.95V (5V max). Frequency at Pin9 (clock) divided by frequency at Pin11 (horizontal out). Clock frequency = 500kHz, clock amplitude same as Note 7. Pulse width measured at 2V point on output waveform. Total capacity = 50pF when measuring pulse width. Sync serrations = 8. Sync amplitude: low state 1.2V, high state 4V (6V max with positive sync tips).
Notes (Cont'd): Note14. Frequency at Pin9 (clock) divided by frequency at Pin3 (ramp control). Note15. Initilize or repeat initilization procedure before doing this test. Note16. Apply a pulse 1 clock wide, 7808 clocks after first positive transition at Pin3. Note17. Default count determined by 684 x 16(H) = 10944. Note18. Sync serrations = 9. Note19. Hold-off count determined by 492 x 16(H) = 7872. Note20. Number of clocks occurring within ramp gate period. Note21. Number of clocks occurring during the blanking gate period. Note22. This series of tests checks the mode recognition circuits. The first test after initialization applies 9 serrations at the sync input pin. The IC should go to the synchronous count ratio of 8400. During the next seven fields only 8 serrations are applied. The NTE849 should maintain the synchronous count ratio of 8400 for the first six fields. At the seventh field the NTE849 should go to default count of 10944. The test concludes with a 9-serration input. The NTE849 should revert to a synchronous count of 8400. Note23. This test checks the operation of the out-of-sync detector by applying out-of-phase sync pulses to Pin12. The NTE849 will count eight fields before resetting to the sync pulse. Note24. Initialize by 8364 sync for eight fields before test. Note25. This test verifies the operation of the fast resync performance by simulating a noise pulse (5 to 50 clocks wide) applied to the IV pin 4000 to 6000 clocks (8ms to 12ms) after IV sync. Initialize to non-sync mode before performing this test. The IC should resync in the next field and be maintained for the standard confidence count of seven fields.
Pin Connection Diagram VCC 1 Vertical Height Ramp Charge Cap External Bias Load 2 3 4 14 GND 13 Comp Sync Input 12 Vertical Sync Input 11 To Horizontal Deflection Circuit 10 Async Time Constant 9 8 32 x Horizontal Mode Select
Yoke Feedback 5 Vertical Driver Vertical Blank Output 6 7
14
8
1
7
.785 (19.95) Max .200 (5.08) Max
.300 (7.62)
.100 (2.45) .600 (15.24)
.099 (2.5) Min

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