ML6440 CCIR601 CCIR601/SQ H44-14 NTSC/CCIR601 PAL/CCIR601 24-BIT 12-BIT 60-LINE

PRELIMINARY ML6440* Multi-Standard 8-bit Adaptive Digital Input Comb Filter GENERAL DESCRIPTION FEATURES The ML6440 SmartCombTM

July 1999 PRELIMINARY ML6440 ML6440* Multi-Standard 8-bit Adaptive Digital Input Comb Filter GENERAL DESCRIPTION FEATURES The ML6440 ML6440 SmartCombTM is a single-chip, 8-bit digital comb filter that incorporates line delays and adaption algorithms for NTSC and PAL at both CCIR601 CCIR601 and square pixel rates. The ML6440 ML6440 implements bandsplit filters and a proprietary adaption and decision logic block that allows for optimum combing over a wide range of video sources. s SmartComb algorithm for automatic or manual selection adaption thresholds s 3-line comb with 60+ line frame adjust s Comb/notch thresholds set dynamically over 60+ lines automatically s 12-bit processing minimizes truncation errors and maintains signal-to-noise performance s Optional 8-bit composite or separated Y/C digital inputs s Applications: digital TV, line doubler, imaging s Separate comb/notch filter thresholds for Luma and Chroma channels s Optional pin controls or two-wire serial control interface s Operating power dissipation less than 700mW s No external components, except diode and caps The ML6440 ML6440 contains all the necessary circuitry to provide high quality combed output of luminance and chrominance in the Y/C format. Internal filters with integrated adaption and compensation circuits provide filtered outputs with optimal video bandwidth and resolution while suppressing cross-color (rainbow), crossluminance (dot crawl) and other corrupting artifacts that can reduce video compression efficiency. * This Part Is End Of Life As Of August 1, 2000 BLOCK DIAGRAM 5 16 VCC 20 21 22 23 24 25 7 Y7 DIGITAL YI1/CV1 Y6 LUMA BYPASS YI2/CV2 YI3/CV3 LUMINANCE OUTPUT BUFFER 19 1HDL HIGH BAND YI4/CV4 YI5/CV5 LOW BAND YI6/CV6 YI7/CV7 CLK 8 9 10 RST MUX 1HDL CLOCK BUFFER BANDSPLIT FILTERS (NOTCH/DELAY) 15 Y3 Y2 COMB ADAPTION AND DECISION LOGIC TOTAL BAND CI0/DI0 PAL/NTSC MODE OE C7 CI1/DI1 CCIR601/SQ CCIR601/SQ. PIXEL MODE D1 C6 HIGH BAND D2 CI3/DI3 COMB MODE 1 D3 LOW BAND CHROMA BYPASS CI6/DI6 THRESHOLD CONTROL 2 D6 CONTROL CI7/DI7 Y+C/CV INPUT MODE 26 C5 C4 C3 C2 C1 C0 D7 S DATA S/P 28 GND S CLK 29 31 32 33 34 35 36 37 GND 17 40 41 42 43 44 1 2 3 GND 4 27 DIGITAL D0 CI2/DI2 COMB MODE 0 30 SmartCombTM HIGH BAND 13 14 Y4 Y0 RESET LOGIC FILTER AND CI4/DI4 THRESHOLD CONTROL 0 D4 COMB 12 CONTROL CI5/DI5 THRESHOLD CONTROL 1 D5 11 Y5 Y1 LOW BAND 6 DIGITAL VCC CHROMINANCE OUTPUT BUFFER 18 YI0/CV0 39 AVCC 38 1 ML6440 ML6440 PIN CONFIGURATION C2 C1 C0 GND Y3 Y2 Y1 Y0 GND VCC C7 C6 C5 C4 C3 ML6440 ML6440 44-Pin TQFP (H44-14 H44-14) 44 43 42 41 40 39 38 37 36 35 34 44 43 42 41 40 39 38 37 36 35 34 33 1 33 2 32 2 32 3 31 3 31 4 30 4 30 1 Y4 Y5 Y6 Y7 VCC 55 29 29 S CLK RST 66 28 28 S DATA YI6/CV6 CI4/DI4 TOP VIEW 2 YI4/CV4 10 24 10 24 11 23 11 23 12 13 14 15 16 17 18 19 20 21 22 12 13 14 15 16 17 18 19 20 21 22 CI3/DI3 YI3/CV3 CI2/DI2 YI2/CV2 YI7/CV7 YI1/CV1 25 25 YI0/CV0 99 GND S/P CI1/DI1 AVCC OE 26 26 CI7/DI7 27 27 88 CI6/DI6 77 CI5/DI5 CLK CI0/DI0 YI5/CV5 ML6440 ML6440 PIN DESCRIPTION PIN NAME FUNCTION PIN NAME FUNCTION 1 C2 Chrominance output 20 YI2/CV2 Luma or composite video input signal 2 C1 Chrominance output 21 YI3/CV3 Luma or composite video input signal 3 C0 Chrominance output 22 YI4/CV4 Luma or composite video input signal 4 GND Digital ground pin 23 YI5/CV5 Luma or composite video input signal 5 VCC Digital supply pin 24 YI6/CV6 Luma or composite video input signal 6 RST Reset input active low. Resets comb logic including the internal data register. Required at power up. 25 YI7/CV7 Luma or composite video (MSB) input signal 26 S/P 7 CLK TTL compatible clock reference 8 CI0/DI0 (LSB) Input Chrominance signal (PAL/ NTSC control pin in control pin mode: register bit D0) Serial/Parallel program mode. If high, allows 8-bit parallel control using the eight digital chrominance input pins. Data clocks in on the positive edge transition. If low, serial port active. 27 OE 9 CI1/DI1 Input Chrominance signal (Square Pixel/CCIR control pin in control pin mode: register bit D1) Output enable. (Y[7:0] and C[7:0]) If low, outputs high impedance. 28 S DATA Serial data input 29 S CLK Serial clock input. Positive-edge clocks. 30 Y7 TTL compatible luminance output (MSB) 31 Y6 Luminance output Input Chrominance signal (Adaption Threshold 0 control pin in control pin mode: register bit D4) 32 Y5 Luminance output 33 Y4 Luminance output Input Chrominance signal (Adaption Threshold 1 control pin mode: register bit D5) 34 Y3 Luminance output 35 Y2 Luminance output Input Chrominance signal (Adaption Threshold 2 control pin mode: register bit D6) 36 Y1 Luminance output 37 Y0 Luminance output (LSB) (MSB) Input Chrominance (Y+C/YI control pin in control pin mode: register bit D7) 38 GND Digital ground pin 39 VCC Digital supply pin 10 CI2/DI2 Input Chrominance signal. (Comb mode 0 control pin in control pin mode: register bit D2) 11 CI3/DI3 Input Chrominance signal (Comb mode 1 control pin in control pin mode: register bit D3) 12 13 14 15 CI4/DI4 CI5/DI5 CI6/DI6 CI7/DI7 16 AVCC Analog supply pin. Bypass to ground with 1µF ceramic capacitor 40 C7 TTL compatible chrominance output (LSB) 17 GND Ground pin for analog delay line 41 C6 Chrominance output 18 YI0/CV0 TTL compatible (LSB) Input composite video signal or Y in the Y+C bypass mode 42 C5 Chrominance output 43 C4 Chrominance output Luma or composite video input signal 44 C3 Chrominance output 19 YI1/CV1 3 ML6440 ML6440 ABSOLUTE MAXIMUM RATINGS Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. Junction Temperature . 150°C Storage Temperature Range. 65°C to 150°C Lead Temperature (Soldering, 10 sec) . 260°C Thermal Resistance (qJA) . 67°C/W VCC . 7V Analog & Digital I/O . GND 0.3V to VCC + 0.3V Input Current . 20µA OPERATING CONDITIONS Temperature Range . 0°C to 70°C VCC Range . 4.75V to 5.25V ELECTRICAL CHARACTERISTICS Unless otherwise specified, VCC = 5V ±5%, CL = 50pF, TA = Operating Temperature Range (Notes 1, 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 60 90 mA VCC0.6 VCC0.4 V 0.8 V SUPPLY ICC AVCC Supply Current VCC=5.25V, CLK=14.75 MHz, PAL Square Pixel Analog Supply Voltage Recommend Operation LOGIC VIL Low Level Input Voltage VIH High Level Input Voltage IIL Low Level Input Current 10 µA IIH High Level Input Current 10 µA CIN Input Capacitance VOL Low Level Output Voltage IOL = 2mA VOH High Level Output Voltage IOH = 2mA Output Current 3-state Mode Output Capacitance 3-state Mode COUT VCC 1.5 V 5 pF 0.4 VCC 1.0 V V 10 µA 5 pF Square Pixel PAL 14.75 MHz Square Pixel NTSC 12.70 MHz CCIR601 CCIR601 13.50 MHz SYSTEM TIMING fCLK tSU CLK Input Frequency fCLK = 14.75MHz Clock Low Duration fCLK = 14.75MHz 30 ns Clock High Duration fCLK = 14.75MHz 45 ns Input Rise Time fCLK = 14.75MHz, 10% to 90% 20 ns Input Fall Time fCLK = 14.75MHz, 90% to 10% 20 ns Data Valid after Rising CLK Edge fCLK = 14.75MHz 3-state Delay Time, Output Enable fCLK = 14.75MHz 20 ns 3-state Delay Time, Output Disable fCLK = 14.75MHz 20 ns Output Rise time fCLK = 14.75MHz, 10% to 90% 20 ns Output Fall time 4 Setup Time to Rising CLK Edge 10 ns fCLK = 14.75MHz, 90% to 10% 20 ns 20 ns ML6440 ML6440 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER (Continued) CONDITIONS MIN TYP MAX UNITS VIDEO SIGNAL PROCESSING Effective Luminance Bandwidth NTSC/PAL, Comb On at 3dB (Note 3) NTSC/CCIR601 NTSC/CCIR601, Comb Off at 3dB 2.5 MHz NTSC/Sq. Pixel , Comb Off at 3dB 2.5 MHz PAL/CCIR601 PAL/CCIR601 , Comb Off at 3dB 2.5 MHz PAL /Sq. Pixel, Comb Off at 3dB 2.5 MHz Effective Chrominance Bandwidth NTSC/PAL, Comb On at 3dB (Note 3) Centered at fSC NTSC/CCIR601 NTSC/CCIR601, Comb Off at 3dB 1.0 MHz NTSC/Sq. Pixel, Comb Off at 3dB 1.0 MHz PAL/CCIR601 PAL/CCIR601, Comb Off at 3dB 1.0 MHz PAL /Sq. Pixel, Comb Off at 3dB 1.0 MHz COMB FILTER CHARACTERISTICS SNRC Signal to Noise Ratio, Chrominance Spurious Luma Artifact NTSC 48 dB 45 dB 48 dB 45 dB 35 dB 13.5MHz PAL 12.27MHz SNRL Signal to Noise Ratio, Luminance Spurious Subcarrier Artifact NTSC 13.5MHz PAL 12.27MHz Comb Notch Depth at fSC Comb Notch Bandwidth at 30dB NTSC/PAL 500 kHz 5 ML6440 ML6440 ELECTRICAL CHARACTERISTICS SYMBOL (Continued) PARAMETER CONDITIONS MIN TYP MAX UNITS SERIAL BUS LOGIC INPUT Low Level Input Voltage 0 0.8 V High Level Input Voltage VCC 0.8 VCC V Low Level Input Current VIN = 0V 1.0 µA High Level Input Current VIN = VCC D 1.0 µA Input Impedance fCLK = 100kHz 1 2 Input Capacitance (CIN) MW pF SYSTEM TIMING SCLK Frequency (fCLOCK) 100 Input Hysteresis (VHYS) 0.2 Spike Suppression (tSPIKE) Max length for zero response Power Setup Time to Valid Data Inputs VCC Settled to Within 1% kHz V 50 ns 10 ms Wait Time From STOP to START On SDATA (tWAIT) 1.3 µs Hold Time for START On SDATA (tHD/START) 0.6 µs Setup Time for START On SDATA (tSU/START) 0.6 µs Min LOW Time On SCLK (tLOW) 1.3 µs Min HIGH Time On SCLK (tHI) 0.6 µs Hold Time On SDATA (tHD/DATA) Setup Time On (tSU/DATA) 5.0 µs Fast mode (Note 4) 100 ns Slow mode (Note 4) 250 ns Rise Time for SCLK & SDATA (tLH) 300 ns Fall Time for SCLK & SDATA (tHL) 30 300 ns Setup Time for STOP On SDATA (tSU/STOP) Note 1: 30 0.6 Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions. Note 2: Supply voltage fed through 7.5W resistor to all VCC pins. Note 3: No bandlimiting is performed on the signal bandwidth when the comb is in the "on" state. Note 4: Parameter is luma dependent 6 µs ML6440 ML6440 FUNCTIONAL DESCRIPTION The ML6440 ML6440 is an adaptive digital comb filter that offers automatic self-adjusting or manual thresholds to handle vertical and horizontal contouring during Y/C separation. The ML6440 ML6440 implements a SmartComb algorithm where full bandwidth video and artifact suppression techniques are used to automatically select suppression thresholds for all video content. Video artifacts such as hanging dots, dot crawl, and cross luminance are dramatically reduced. The algorithm functionally performs a statistical analysis of the video content of over 60 lines. It then calculates and selects the best threshold for artifact reduction at 12-bit resolution. The ML6440 ML6440 is a comb for NTSC (525 lines) and PAL (625 lines) with the ability to handle CCIR601 CCIR601 and square pixel sampling rates. CCIR601 CCIR601 is the existing standard for digitized video of either NTSC or PAL at a 13.5MHz rate, and is used by MPEG encoders and decoders for image compression. The comb algorithms in the comb filter substantially reduce rainbow and dot-crawl artifacts which interfere with efficient image compression. Square pixel is video digitized at 12.27MHz for NTSC, and 14.75MHz for PAL, so that each sample corresponds to a single pixel in computer displays without the effort or expense of a multi-phase image resizing filter done in hardware or software. Using the ML6440 ML6440 comb filter requires no external components for operation. The comb filter can be bypassed to accommodate selection of external S-video signals. The comb filter is controllable via parallel pin or serial interface. CVIN SMARTCOMB OPERATION The user supplies 8-bit video as either digital Y/C or digital composite video inputs and receives delayed and combed data at the Y/C digital outputs. Use of Y/C input assumes that combing is unnecessary and sends the data through the same delay as the composite video path to prevent shifting of the video position on the screen. This makes the ML6440 ML6440 useful in source selection such as S-video inputs and composite video. Composite video (CV), applied to the ML6440 ML6440 with comb operation enabled, permits the separation of luminance and chrominance with minimal artifacts. The SmartComb controls the application of the comb filter and bandsplit-notch filters on a pixel-by-pixel basis. The digital video image is sampled, and an analysis is performed. SmartComb step 1: looks for differences in the low frequency spectra (vertical detail). SmartComb step 2: searches for changes in phase angle/saturation of the chroma sub-carrier, which represents changes in color in the vertical direction. Finally, SmartComb step 3: an averaging circuit is used as "smoothing function" to eliminate dithering in the horizontal dimension caused by excessive filter switching. Figure 1 provides a simplified block diagram of the SmartComb architecture. This architecture implements several complex computations to determine the amount of notch vs. comb filtering. Three 8-Bit detectors are used to examine vertical and horizontal detail for luma and chroma signals on a pixel-by-pixel basis for 3-line analysis. These data are then fed into a weighting function to determine the best filtering approach over the existing 3-lines of video. Furthermore, this data is then compared 1H VIDEO SIGNALS 1H HI-BAND HI-BAND HI-BAND LOW BAND LOW BAND LOW BAND LUMA VERTICAL DETAIL DETECTOR 8-BIT AUTOMATIC THRESHOLD SELECT COMB/NOTCH CONTROL FUNCTION 24-BIT 24-BIT, 3-LINE LUMA HORIZONTAL DETAIL DETECTOR 8-BIT COMB/NOTCH THRESHOLD SELECT CHROMA VERTICAL DETAIL DETECTOR 8-BIT MANUAL THRESHOLD SELECT COMP FADER COMB/NOTCH CONTROL FUNCTION 12-BIT 12-BIT, FRAME, 60-LINE 60-LINE MIXER 8-BIT YOUT COUT Figure 1. SmartComb Architecture: Simplified Block Diagram 7 ML6440 ML6440 PREAMBLE DATA ADDRESS (B3)HEX DATA (D[7:0]2) Table 1. Serial Data Format BIT D7 D6 D5 D4 D3 D2 D1 D0 Y+C or CV Select Adaption Threshold 2 Adaption Threshold 1 Adaption Threshold 0 Comb Mode 1 Comb Mode 0 Square Pixel/ CCIR601 CCIR601 Select PAL or NTSC Select Value Y+C = 1 CV = 0 AT2 = 0 or 1 AT1 = 0 or 1 AT0 = 0 or 1 CM1 = 0 or 1 CM0 = 0 or 1 Sq. Pixel = 1 CCIR601 CCIR601 = 0 PAL = 1 NTSC = 0 Parallel Mode Input Pin CI7/DI7 CI6/DI6 CI5/DI5 CI4/DI4 CI3/DI3 CI2/DI2 CI1/DI1 CI0/DI0 Mode-Function Table 2. Control Register Format D[7:0] (Serial or Parallel Mode) STANDARD/RATE CCIR601 CCIR601 SQUARE PIXEL NTSC (fSC = 3.58MHz) 13.5MHz 12.27MHz PAL (fSC = 4.43MHz) 13.5MHz 14.75MHz Table 3. Clock Frequency Requirements ADAPTION THRESHOLD D[6,5,4] ADAPTION THRESHOLD LEVEL 000 Automatic threshold for minimal comb artifact generation for various video source material. 001 Threshold for computer graphics applications, minimizing dot crawl on bold lettering. 010 to 110 111 Various degrees of thresholds. Threshold for better reproduction of natural photographic images. Table 4. Adaption Threshold Bit Table COMB MODE, D[3,2] NTSC PAL 00 Y adaptive, C comb 100% active Y adaptive, C adaptive 01 Y adaptive, C adaptive Y adaptive, C comb 100% active 10 Y 100% comb active, C 100% comb active Y 100% comb active, C 100% comb active Not recommended due reduced performance 11 Bandsplitting only (no combing) Table 5. Comb Mode Bit Table 8 Bandsplitting only (no combing) ML6440 ML6440 START S DATA tRISE tFALL All Other S DATA Transitions Must Occur While S CLK is Low tSET/START S CLK STOP START: A Falling Edge on the S DATA While S CLK is Held High STOP: A Rising Edge on the S DATA While S CLK is Held High Figure 2. Definition of START & STOP on Serial Data Bus S DATA MSB MSB A7 A6 A1 A0 D7 D6 D1 D0 STOP S CLK 0 1 2 7 8 9 10 11 16 17 18 S CLK: 9th pulse strobes address decoder S DATA: Rising edge with S CLK Hi = STOP S CLK: Rising edge enables data transfer S DATA: Value set low in prep for STOP S DATA: Value set to A6, Device Address (MSB-1) S CLK: 18th pulse strobes data shift register S CLK: Falling edge disables data transfer S CLK: Rising edge enables data transfer S CLK: Rising edge enables data transfer S DATA: Value set to D6, Data MSB-1 S DATA: Value set to A7, Device Address MSB S CLK: Falling edge disables data transfer S CLK: Falling edge in prep for first address transfer S CLK: Rising edge enables data transfer S DATA: Falling edge w/S CLK high means start of sequence S DATA: Value set to D7, Data MSB Figure 3. Definition of DATA FORMAT on Serial Data Bus S DATA STROBE (ACK) `1' `0' `1' `1' `0' `0' `1' `1' Ø D7 D6 D5 DEVICE ADDR = `B3' D4 D3 D2 D1 D0 Ø G H I CONTROL REGISTER S CLK 0 1 2 3 S CLK: 4 5 6 7 8 9 A B C E F Address decode strobed on 9th clock [Data is `don't care' during strobe] S DATA: `1011 0011' shifted on next 8 clocks S CLK: D SDATA: Final Clock strobes data into register Control register, load MSB first Falling edge in prep for device address transfer Figure 4. Typical Serial Bus Command 9 ML6440 ML6440 FUNCTIONAL DESCRIPTION (Continued) to the video content of the last 60+ lines (frames) of video -a frame weighing function- to determine the best filtering approach of the current video content. Finally, 1 of 7 thresholds can be chosen to adjust either real-time (automatically) by the ML6440 ML6440 itself or fixed manually by design. An internal 12-bit analysis is used for the filtering algorithm. An additional fader circuit is included to "smooth" the transitions between comb and notch filtering. In NTSC, every other line of chroma is inverted while there are no changes in luma (assuming there is no change in color between adjacent lines). This permits data to be added from the first stored line of data with the third line of active high-band video data, each with a scaling of 0.25, and add the second stored line of data with a scaling of 0.50. The result contains no chroma, only luma information. Subtracting this information from the highband signal yields only chroma information. In PAL, each line of data rotates the phase of the chroma by 90 degrees. Therefore, by adding the first line of stored high-band information from the active third line, the chroma is canceled, leaving only luma information. Once again, this information is subtracted with the appropriate amplitude scaling from the original highband information to yield only chroma. In bandsplit (notch) filtering and luma peaking, the digital bandsplit filter is used as an alternate filter when the SmartComb algorithm determines that the comb filter output signal would be contaminated with cross chroma artifacts. To maintain a reasonable amount of apparent resolution in the luminance signal, luma peaking is applied. This helps maintain image quality in the portion of the video image where comb filtering would generate artifacts. The ML6440 ML6440 SmartComb provides a real-time filtering algorithm solution (automatic mode) for a wide variety of video sources without the shortcomings of using fixed thresholds (manual mode). The automatic threshold tracking circuit responds quickly, adjusting itself in about 1/300th of a second (about 60 lines). The transition from the comb to the digital bandsplit is made with a continuous digital fader to prevents switching glitches. The bandsplit-notch and comb filters were designed to reduce color bar peak-to-peak dot edge crawl to