ML6428. S-Video Filter and 75Ω Line Drivers with Summed Composite Output. Features. General Description. Block Diagram Σ BUFFER.

Transcription

1 ML S-Video Filter and Line Drivers with Summed Composite Output Features.MHz Y and C filters, with CV out for NTSC or PAL cable line driver for Y, C, CV, and TV modulator db stopband attenuation at MHz db flatness up to.mhz No external frequency select components or clocks ns group delay flatness up to 0MHz % overshoot on any input edge AC coupled input and output (MLCS-) AC coupled input and DC coupled output (MLCS-) 0.% differential gain on all channels, 0.º differential phase on all channels 0.% total harmonic distortion on all channels V ±0% operation DC restore with low tilt General Description The ML is a dual Y/C th-order Butterworth lowpass video filter optimized for minimum overshoot and flat group delay. The device also contains a summing circuit to generate filtered composite video. The Y and C input signals from DACs are AC coupled into the ML. Both channels have DC restore circuitry to clamp the DC input levels during video sync. The Y channel uses a sync tip clamp. The CV and the C channels share a feedback clamp. All outputs must be AC coupled into their loads for the - version. The - version must be DC coupled. All inputs (- and - versions) are AC coupled. The Y or C outputs can drive VP-P into a 0Ω load, while the CV output can drive VP-P into. Thus the CV output is capable of driving two independent 0Ω loads to VP-P. On the CV output, one of the loads can be shorted to ground with no loss of drive to the remaining load. The Y, C and CV channels have a gain of (db) with VP-P input levels. Block Diagram VCC VCCO BUFFER SYNC TIP CLAMP Σ BUFFER TRANSCONDUCTANCE ERROR AMP BUFFER GND REV. C April 00

2 ML DATA SHEET Pin Configuration ML -Pin SOIC (S0) VCC VCCO GND TOP VIEW Pin Description Pin Name Function Luminance input VCC V supply for filters and references GND Ground Chrominance input Chrominance output Composite video output VCCO V supply for output stages Luminance output Electrical Characteristics 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. Operating Conditions Parameter Min. Max. Units DC Supply Voltage -0. V Analog & Digital I/O GND 0. VCC 0. V Output Current (Continuous) CV Channel C and Y Channels Junction Temperature 0 C Storage Temperature Range 0 C Lead Temperature (Soldering, 0 sec) 0 C Thermal Resistance (θja) C/W Parameter Min. Max. Units Temperature Range 0 0 C VCC Range.. V 0 0 ma ma REV. C April 00

3 DATA SHEET ML Electrical Table Unless otherwise specified, VCC = V ±0%, All inputs AC coupled with 00nF, ML- outputs must be AC coupled, ML- outputs must be DC coupled. TA = Operating Temperature Range Symbol Parameter Conditions Min. Typ. Max. Units ICC Supply Current No Load (VCC =.0V) 0 ma AV Low Frequency Gain (All Channels) VIN = 00mVP-P at 00KHz..0. db C DC Output Level (During Sync) Sync Present on Y..9. V Y Sync Output Level ML- Sync Present on Y V ML- Sync Present on Y V YC Sync Output ML- Sync Present on Y V Level ML- Sync Present on Y V tclamp Clamp Response Time (Y Channel) Settled to Within 0mV ms fdb -db Bandwidth (Flatness).0. MHz (All Channels) fc -db Bandwidth (Flatness). MHz (All Channels) 0.fC 0. x fc Attenuation (Y, C). db fsb Stopband Rejection (All Channels) fin = MHz to 00MHz worst case db Vi Input Signal Dynamic Range AC Coupled ML-, -.0. VP-P NOISE Output Noise (All Channels) Hz to 0MHz. mvrms OS Peak Overshoot (All Channels) VP-P Output Pulse (loaded). % ISC Output Short Circuit Current (All Channels) VOUT C, Y, or CV (Note ) 00 ma CL Output Shunt Capacitance All Outputs pf (All Channels) dg Differential Gain (All Channels) All Outputs 0. % dφ Differential Phase (All Channels) All Outputs 0. THD Output Distortion (All Channels) VOUT =.VP-P, 0. % Y/C Out at.mhz/.mhz XTALK Crosstalk From C Input of 0.VP-P at.mhz/.mhz, to Y Output db From Y Input of 0.VP-P at db.mhz, to C Output PSRR PSRR (All Channels) 0.VP-P (00kHz) at VCC 9 db tpd Group Delay (All Channels) 00kHz 0 ns tpd Group Delay Deviation from to.mhz (NTSC) ns Flatness to.mhz (PAL) without (All Channels) peaking (see Figures to ) ns to 0MHz ns tskew Skew Between Y & C Outputs ns Note : Limits are guaranteed by 00% testing, sampling, or correlation with worst case test conditions. : Sustained short circuit protection limited to 0 seconds. REV. C April 00

4 ML DATA SHEET Functional Description The ML is a dual monolithic continuous time video filter designed for reconstructing the luminance and chrominance signals from an S-Video D/A source. Composite video output is generated by summing the Y and C outputs. The MLCS- is intended for use in AC coupled input and output applications. The MLCS- is intended for AC coupled input and DC coupled output applications (see Figures and ). The filters have a th-order Butterworth characteristic with an optimization toward low overshoot and flat group delay. All outputs are capable of driving VP-P into 0Ω video loads, with up to pf of load capacitance at the output pin. MLCS- outputs are AC coupled, MLCS- outputs are DC coupled. The CV output can drive two video loads plus a high-impedance modulator. Thus the CV output is intended to simultaneously drive a VCR, a TV, and a highimpedance modulator. Y and C are capable of driving a load at VP-P. The ML is capable of driving two composite loads and a TV modulator simultaneously. All channels are clamped during sync to establish the appropriate output voltage swing range. Thus the input coupling capacitors do not behave according to the conventional RC time constant. Clamping for all channels settles within ms of a change in video input sources. In most applications, the ML's input coupling capacitors are. The Y input sinks.µa during active video, which nominally tilts a horizontal line by mv (max) at the Y output (Figure ). During sync, the clamp typically sources 0µA to restore the DC level. The net result is that the average input current is zero. Any change in the input coupling capacitor's value will inversely alter the amount of tilt per line. Such a change will also linearly affect the clamp response times. The C channel has no pulldown current sources and is essentially tilt-free. Its input is clamped by a feedback amp which responds to the CV output. Since CV = YC, the CV output will droop by the same amount as Y during active video, and will rise by the same amount as Y during sync. The ML is robust and stable under all stated load and input conditions. Capacitavely bypassing both VCC pins directly to ground ensures this performance. (See Figures and ) capacitance (at the output pin) can be driven without stability or slew issues. A AC coupling capacitor is recommended at the output (ML- only). Chrominance (C) I/O The chroma input is driven by a low impedance source of 0.VP-P or the output of a terminated line. The input is required to be AC coupled via a 0.uF coupling capacitor which allows for a nominal clamping time of ms. The chroma output is capable of driving a 0Ω load at VP-P or VP-P into a load. MLCS- outputs are AC coupled, MLCS- outputs are DC coupled. Up to pf of load capacitance can be driven without stability or slew issues. A AC coupling capacitor is recommended at the output (ML- only). Composite video (CV) output The composite video output is capable of driving CV loads to VP-P and a high input impedance CV modulator. MLCS- outputs are AC coupled, MLCS- outputs are DC coupled. It is intended to drive three devices: TV, VCR, and a modulator. The TV or VCR input can be shorted to ground and the other outputs will still meet specifications. Up to pf of load capacitance (at the output pin) can be driven without stability or slew issues. Using the ML for PAL Applications The ML can be optimized for PAL video by adding frequency peaking to the composite and S-video outputs. Figures and illustrate the use of a additional external capacitor,, added in parallel to the output source termination resistor. This raises the frequency response from. db down at.mhz to 0.dB down at.mhz allowing for accurate reproduction of the upper sideband of the PAL subcarrier. Figure 9 shows the frequency response of PAL video with various values of peaking capacitors (0pF, 0pF, 0pF, ) between 0 and 0MHz. For NTSC applications without the peaking capacitor the rejection at MHz is db (typical) while for PAL applications with the peaking capacitor the rejection at MHz is db (typical). This is shown in Figure 0. The differential group delay is shown in Figure with and without a peaking capacitor (0pF, 0pF, 0pF, and ) varies slightly with capacitance, going from ns to ns. Luminance (Y) I/O The luma input is driven by either a low impedance source of VP-P or the output of a terminated line. The input is required to be AC coupled via a 0.uF coupling capacitor which allows for a nominal settling time of ms. The luma output is capable of driving a 0Ω load at VP-P or VP-P into a load. MLCS- outputs are AC coupled, MLCS- outputs are DC coupled.up to pf of load REV. C April 00

5 DATA SHEET ML AMPLITUDE (db) AMPLITUDE (db) Figure. Passband Flatness All outputs. (Normalized) Passband is ripple-free. Figure. Passband/Stopband Rejection Ratios All outputs. (Normalized) 90 0 DELAY (ns) 0 0 SCALE: 00ms/DIV Region of Tilt SCALE: 00ms/DIV Figure. Group Delay, all Outputs Low frequency group delay is ns. At.MHz group delay increases by only ns. At.MHz group delay increases by only ns. The maximum deviation from flat group delay of ns occurs at MHz. Figure. DC Restore Performance of Luma Output Luma ramp test pattern is shown to have minimal tilt during vertical sync. In most applications, the ML's input coupling capacitors are. The Y input sinks.µa during active video, which tilts a horizontal line by mv at the Y output REV. C April 00

6 ML DATA SHEET Typical Applications ML- Σ VIDEO CABLES V C* R* ON-CHANNEL MODULATOR, VCR, AND TV µf * C AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD Figure. AC Coupled S-Video and Composite Video Line Driver for NTSC (Note: ML- outputs must be AC coupled) ML- VIDEO CABLES Σ V C* R* ON-CHANNEL MODULATOR, VCR, AND TV µf * C AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD Figure. DC Coupled S-Video and Composite Video Line Driver for NTSC (Note: ML- outputs must be DC coupled) REV. C April 00

7 DATA SHEET ML Typical Applications ML- V Σ C* R* C* VIDEO CABLES ON-CHANNEL MODULATOR, VCR, AND TV µf * C, C, AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD Figure. AC Coupled S-Video and Composite Video Line Driver for PAL (Note: ML- outputs must be AC coupled) ML- VIDEO CABLES Σ V C* R* C* ON-CHANNEL MODULATOR, VCR, AND TV µf * C, C, AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD Figure. DC Coupled S-Video and Composite Video Line Driver for PAL (Note: ML- outputs must be DC coupled) REV. C April 00

8 ML DATA SHEET 0. AMPLITUDE (db) pF 0pF 0pF 0.dB WITH.dB WITHOUT. 0 Figure 9. NTSC/PAL Video Frequency Response With and Without Peaking Capacitor 0 0 AMPLITUDE (db) pF 0pF 0pF NTSC/PAL db WITHOUT NTSC/PAL db WITH Figure 0. Stopband Rejection at MHz With and Without Peaking Capacitor 0 0 ns GROUP DELAY WITHOUT DELAY (ns) 0 ns GROUP DELAY WITH 0pF 0pF 0pF Figure. Group Delay at.mhz (PAL) With and Without Peaking Capacitor REV. C April 00

9 DATA SHEET ML Mechanical Dimensions inches (millimeters) (.0 -.0) Package: S0 -Pin SOIC PIN ID (. -.0) (.9 -.0) ( ) ( PLACES) 0.00 BSC (. BSC) (.9 -.) (.0 -.) (0.0-0.) SEATING PLANE (0.0-0.) ( ) ( ) REV. C April 00 9

10 ML DATA SHEET Ordering Information Model Part Number Lead Free Package Container Pack Quantity ML MLCS SOIC- Rail 9 ML MLCSX SOIC- Reel 00 ML MLCSX_NL SOIC- Reel 00 ML MLCS SOIC- Rail 9 ML MLCSX SOIC- Reel 00 Temperature range for all parts: -0 C to C DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein:. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user.. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness Fairchild Semiconductor Corporation