LMH1251

LMH1251 YPBPR to RGB Decoder and 2:1 Video Switch August 2005 LMH1251 YPBPR to RGB Decoder and 2:1 Video Switch General Description The LMH™1251 is a wideband 2:1 analog video switch with an integrated YPBPR to RGB decoder. The device accepts one set of YPBPR inputs and one set of RGB/HSYNC/ VSYNC inputs. Based on the input selected, the output will be either a decoded TV or buffered PC video signal. The LMH1251 has a SYNC separator and processor that is capable of extracting sync timing information from both Standard Definition Television (SDTV) and High Definition Television (HDTV) inputs. It provides bi-level sync, and tri-level sync separation. The color space conversion from YPBPR to RGB in the LMH1251 is realized with a very high precision fully analog dematrixer that provides chrominance accuracy that is less than 2.5% of amplitude & 1.5˚ of phase error on a vectorscope. It is equipped with a smart video detection circuit which automatically senses SDTV and HDTV video formats and applies the appropriate color space conversion. The LMH1251 is capable of handling SDTV, HDTV, XGA, SXGA, and UXGA video formats, which makes it an ideal solution for enhancing value in applications ranging from LCD monitors, to set-top boxes, to projectors. The LMH1251 is available in a TSSOP-24 package. Features YPBPR to RGB decoding YPBPR path: 70 MHz, −3 dB, 700 mVPP bandwidth RGB path: 400 MHz, −3 dB, 700 mVPP bandwidth Supports PC video display resolutions up to UXGA (1600 x 1200 @ 75 Hz) n Supports 480i, 480p, 576i, 576p, 720p, 1080i, and 1080p n Smart video format detection for SD and HD n Power save mode n n n n Applications n n n n TFT LCD monitor CRT monitor Set-top box Display projector Connection Diagram 24-Pin TSSOP 20151927 Top View LMH™ is a trademark of National Semiconductor Corporation. © 2005 National Semiconductor Corporation DS201519 www.national.com LMH1251 Truth Table TABLE 1. Input Select Pin 24 0 1 OUT RGBhv input Ch YPBPR input Ch TABLE 2. Pin 23 0 0 1 1 Pin 22 0 1 *Outputs 0 *Outputs 1 SYNC Bi-Level Tri-Level Bi-Level Tri-Level Format Detection Manual Manual Auto Auto Decoding Scheme 480p 720p/180i 480p 720p/1080i Note: * When Pin 23 is set high, the LMH1251 is in Auto Mode, in which it can detect the incoming video format (SD or HD) and apply the appropriate color decoding and sync processing. With Auto Mode, Pin 22 becomes an output pin, and will either output a logic high or low to notify the user of the format that is being detected by the LMH1251. If Pin 23 is set low, the LMH1251 is in Manual Mode, in which the user must specify the format with Pin 22. With Manual Mode, Pin 22 is an input pin. Since Pin 22 is a bi-directional pin, care must be taken to not apply any voltages to it when it is in the Auto Mode, in which it functions as an output pin. The use of the Auto Mode with Pin 22 left floating is typically recommended. TABLE 3. Power Save Pin 21 0 1 Low Power Mode Disable Enabled Ordering Information Package 24-Pin TSSOP Part Number LMH1251MT LMH1251MTX Package Marking LMH1251MT Transport Media 61 Units/Rail 2.5k Units Tape and Reel NSC Drawing MTC24 www.national.com 2 LMH1251 Absolute Maximum Ratings (Notes 1, 3) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance Susceptibility(Note 4) Machine Model (Note 11) Supply Voltage VCC, Pins 7 and 17 Voltage at any Input Pin (VIN) Video Inputs (pk-pk) Thermal Resistance to Ambient (θJA) 4.0 kV 400V Thermal Resistance to Case (θJC) Junction Temperature (TJ) Storage Temperature Range Lead Temperature (soldering 10 sec.) 25˚C/W +150˚C −65˚C to +150˚C 265˚C Operating Ratings (Note 2) 5.5V VCC −0.5 ≥ VIN ≥ 0V 0.0V ≤ VIN ≤ 1.2V 110˚C/W Operating Temperature Range Supply Voltage (VCC) RGB Video Inputs (pk-pk) Y Video Inputs (incl. Sync) PBPR Video Inputs 0˚C to +70˚C 4.75V ≤ VCC ≤ 5.25V 0.0V ≤ VIN ≤ 0.7V -0.3V ≤ VIN ≤ 0.7V -0.35V ≤ VIN ≤ 0.35V Video Signal Electrical Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V, RGB VideoIN = 0.70, Y VideoIN = 0.7 VPP, PBPR VideoIN = ± 350 VmV, CL = 8 pF, Video Outputs = 0.7 VPP. See (Note 7) for Min and Max parameters and (Note 6) for typicals. Symbol IS, RGB IS, YPBPR IS-PS IOUT VO BLK GainRGB Ch-Ch MatchRGB LERGB Parameter Supply Current Supply Current Supply Current, Power Save Mode Output Current Typical DC Active Video Black Level Output Voltage RGB Video Unity Gain RGB Ch to Ch Matching RGB Input: Linearity Error No AC Input Signal RGB VideoIN = 0.7 VPP RGB VideoIN = 0.7 VPP Staircase Input Signal see (Note 9) 10% to 90%, AC Input Signal (Note 5) AC Input Signal (Note 5) 90% to 10%, AC Input Signal (Note 5) AC Input Signal (Note 5) 10% to 90%, AC Input Signal (Note 5) (Note 5), AC Input Signal 10% to 90%, AC Input Signal (Note 5) AC Input Signal (Note 5) 90% to 10%, AC Input Signal (Note 5) AC Input Signal (Note 5) 1.8 Conditions (Note 2) No Output Loading, 80 kHz No Output Loading, 480p see (Note 8) Power Save Mode, No Output Loading, 80 kHz, see (Note 8) Min 28 60 4 Typ 34 70 8 3 2.1 0.07 0.02 0 2.4 Max 41 80 12 Units mA mA mA mA VDC dB dB % Video Time Domain Response RGB tr RGB OSR RGB tf RGB OSF SD YPBPR tr RGB OSF SD YPBPR tr SD YPBPR OSR SD YPBPR tf SD YPBPR OSF RGB Input: Video Rise Time RGB Input: Rising Edge Overshoot RGB Input: Video Fall Time RGB Input: Rising Edge Overshoot SD YPBPR Input: Video Rise Time RGB Input: Falling Edge Overshoot SD YPBPR Input: Video Rise Time SD YPBPR Input: Rising Edge Overshoot SD YPBPR: Video Fall Time SD YPBPR: Falling Edge Overshoot 1.55 3 1.55 3 1.54 3 15.4 3 15.4 3 ns % ns % ns % ns % ns % 3 www.national.com LMH1251 Video Signal Electrical Characteristics Symbol HD YPBPR tr HD YPBPR OSR HD YPBPR tf HD YPBPR OSF Parameter HD YPBPR Input: Video Rise Time HD YPBPR Input: Rising Edge Overshoot HD YPBPR: Video Fall Time HD YPBPR: Falling Edge Overshoot RGB Input: Channel Bandwidth (−3 dB) YPBPR Input (SD & HD): Channel Bandwidth (−3 dB) Video Amplifier 10 MHz Isolation Channel to Channel Video Amplifier 10 MHz Isolation RGB Input to YPBPR Input Signal to Noise Ratio (Continued) Unless otherwise noted: TA = 25˚C, VCC = +5.0V, RGB VideoIN = 0.70, Y VideoIN = 0.7 VPP, PBPR VideoIN = ± 350 VmV, CL = 8 pF, Video Outputs = 0.7 VPP. See (Note 7) for Min and Max parameters and (Note 6) for typicals. Conditions (Note 2) 10% to 90%, AC Input Signal (Note 5) AC Input Signal (Note 5) 90% to 10%, AC Input Signal (Note 5) AC Input Signal (Note 5) Large Signal BW Large Signal BW (Note 12) (Note 12) Min Typ 8.4 3 8.4 3 Max Units ns % ns % Video Frequency Domain Response RGB BW YPBPR BW VSEP Ch-Ch 10 MHz VSEP INPUT-INPUT 400 70 −50 −55 MHz MHz dB dB 10 MHz SNR AC Input Signal, CL = 8 pF (Note 12) 55 dB Unless otherwise noted: TA = 25˚C, VCC = +5.0V, Y VideoIN = 0.7 VPP, PBPR VideoIN = ± 350 VmV, CL = 8 pF, Video Outputs = 0.7 VPP. See (Note 7) for Min and Max parameters and (Note 6) for typicals. Symbol VCOLOR ERROR Parameter |PBPR| Amplitude (Calculated from RGB Outputs) PBPR Phase Angle Calculated from RGB Outputs) Conditions YPBPR Video Input, 100% Color Bar (any 3 colors), (Note 13) YPBPR Video Input, 100% Color Bar (any 3 colors), (Note 13) Min Typ Max Units % Color Decoding Accuracy ± 0.3 ± 2.5 θCOLOR ERROR ± 0.2 ± 1.5 deg Sync Signal Electrical Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V, Y VideoIN = 0.7 VPP, PBPR VideoIN = ± 350 VmV, CL = 8 pF, Video Outputs = 0.7 VPP. See (Note 7) for Min and Max parameters and (Note 6) for typicals. Symbol VSYNCL VSYNCH IO-SYNCH tR/F-SYNC tSYNC-WIDTH tY-SYNC-WIDTH Parameter H & V SYNC Low Input H & V SYNC High Input H & V SYNC Current Sink/Source Capability H & V SYNC Rise/Fall Time H & V SYNC Width Error Relative to H & V SYNC Input H & V SYNC Width Error Relative to Composite SYNCS on Y 50% of H & V SYNC Input to Output H & V SYNC Input Composite SYNC on Y Input Pins 1 & 2 Pins 1 & 2 5 kΩ Load Conditions Min −0.5 3.0 3 15 5 5 Typ Max 1.5 VCC +0.5 Units V V mA ns % % tSYNC-DELAY H & V SYNC Input 40 ns www.national.com 4 LMH1251 Sync Signal Electrical Characteristics Symbol tY-HSYNC-DELAY Parameter 50% of H SYNC Input to Output (Continued) Unless otherwise noted: TA = 25˚C, VCC = +5.0V, Y VideoIN = 0.7 VPP, PBPR VideoIN = ± 350 VmV, CL = 8 pF, Video Outputs = 0.7 VPP. See (Note 7) for Min and Max parameters and (Note 6) for typicals. Conditions Composite SYNC on Y Input (Not During Vertical Period) Min Typ 70 Max Units ns System Interface Signal Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V, Y VideoIN = 0.7 VPP, PBPR VideoIN = ± 350 VmV, CL = 8 pF, Video Outputs = 0.7 VPP. See (Note 7) for Min and Max parameters and (Note 6) for typicals Symbol VIL VIH IL IH VOL Parameter Logic Low Input Voltage (Pins 24, 23, 22, 21) Logic High Input Voltage (Pins 24, 23, 22, 21) Logic Low Input Current (Pins 24, 23, 22, 21) Logic High Input Voltage (Pins 24, 23, 22, 21) Logic Low Output Voltage (Pins 24, 23, 22, 21) Input Voltage = 0.4V Input Voltage = 0.4V IO = 3 mA Conditions Min −0.5 3.0 Typ Max 1.5 VCC +0.5 Units V V µA µA V ± 10 ± 10 0.5 Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications, see the Electrical Characteristics tables. Note 2: Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. All video inputs must be properly terminated. Note 3: All voltages are measured with respect to GND, unless otherwise specified. Note 4: Human Body Model: 100 pF discharged through a 1.5 kΩ resistor. Note 5: Input from RGB signal generator: tr, tf = 1.5 ns. Input from SDTV YPBPR signal generator: tr, tf = 15 ns. Input from HDTV YPBPR signal generator: tr, tf = 8 ns. Note 6: Typical specifications are specified at +25˚C and represent the most likely parametric norm. Note 7: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may change when the device is not operated under the listed test conditions. Note 8: The supply current specified is the quiescent current for VCC and 5V with RL = ∞. Load resistors are not required and are not used in the test circuit; therefore, all the supply current is used by the device. Note 9: Linearity Error is the maximum variation in step height of a 16 step staircase input signal waveform with a 0.7 VPP level at the input. All 16 are steps equal, with each at least 100 ns in duration. Note 10: ∆AV track is a measure of the ability of any two amplifiers to track each other and quantifies the matching of the three gain stages. It is the difference in gain change between any two amplifiers with the contrast set to AVC-50% and measured relative to the AV max condition. For example, at AV max the three amplifiers’ gains might be 12.1 dB, 11.9 dB, and 11.8 dB and change to 2.2 dB, 1.9 dB and 1.7 dB respectively for contrast set to AVC-50%. This yields a typical gain change of 10.0 dB with a tracking change of ± 0.2 dB. Note 11: The Machine Model ESD test is covered by specification EIAJ IC-121-1981. A 200 pF cap is charged to the specific voltage, then discharged directly into the IC with no external series resistor (resistance of discharge path must be under 50Ω). Note 12: Measure output levels of the other two undriven amplifiers relative to the driven amplifier to determine channel separation. Terminate the undriven amplifier inputs to simulate generator loading. Repeat test at fIN = 10 MHz for VSEP 10 MHz. Note 13: Any three color bar signals can be used as test signals. The RGB outputs shall be used to calculate the amplitudes and phases of the chrominance results. These should fall within the limits specified. 5 www.national.com LMH1251 Typical Performance Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V, RGB VideoIN = 0.70, Y VideoIN = 0.7 VPP, PBPR VideoIN = ± 350 VmV, CL = 8 pF, Video Outputs = 0.7 VPP. See (Note 7) for Min and Max parameters and (Note 6) for typicals. Large Signal Frequency Response Crosstalk vs. Frequency 20151903 20151904 Pulse Response Harmonic Distortion vs. Frequency 20151901 20151902 720p Color Bar Vectorscope 20151906 www.national.com 6 LMH1251 Application Notes GENERAL INFORMATION The LMH1251 is a high-speed triple 2:1 video multiplexer with an integrated sync processor and color space converter. One input channel accepts standard RGBHV PC graphics video and the second input channel accepts YPBPR component video. If the first input of the MUX is selected, the device will output the RGBHV video from the input with unity gain. If the second input of the MUX is selected, sync processing and color space conversion will be performed on the YPBPR component signals to provide an equivalent RGBHV signal at the output. YPBPR to RGBHV PROCESSING The LMH1251 is capable of processing 480i, 480p, 576i, 576p, 720p, 1080i, and 1080p/60 YPBPR component video signals only. S-Video, composite NTSC, or composite PAL video will not be decoded by the LMH1251. For High Definition, 720p and 1080i video, the LMH1251 will decode the luminance and color difference signals into primary RGB signals according to the linear arithmetic formula specified in the EIA/CEA-770.3-C Standard for High Definition Analog Component TV. For Standard Definition video, the LMH1251 will perform the decoding according to the linear arithmetic formula specified in the EIA/CEA-770.2-C Standard for Standard Definition Analog Component TV. The advanded analog architecture that is employed to perform the color space conversion is precise to within 2.5% of amplitude & 1.5˚ of phase error on a vectorscope with a color bar test signal. This is illustrated with a vectorscope plot of a decoded color bar signal in the 720p format show in the Typical Performance Characteristics section. Note that although 480i/576i component video is supported by the LMH1251, most PC Display Monitors cannot handle such line rates. Typically, only 480p, 576p, 720p, and 1080i/ 1080p are within the displayable line rate range of LCD and CRT monitors. Furthermore, the scaler in LCD monitor systems must include a de-interlacer for it to display interlaced video such as with 1080i. Component Video Formats supported by the LMH1251 480i 480p 576i 576p 720p 1080i23/25/30 1080p50/59/60 AUTO/MANUAL FORMAT DETECTION The LMH1251 can either automatically detect the input format of the component video source, or it can be put in a manual mode where the MCU has the flexibility to specify which YPBPR to RGBHV processing scheme for the device to apply depending on the input format. If a logic high is applied to Pin 23, the LMH1251 will be in the AUTO detection mode, which is typically recommended. In this mode, the device will appropriately use the correct YPBPR to RGBHV processing scheme based on its input format detection. If a logic high is applied to Pin 23, the LMH1251 will be in the Manual detection mode. In this mode, the MCU must apply a logic low to Pin 22 if the processing scheme is for SD Video formats, and a logic high if the processing scheme is for HD Video formats. Note that in the AUTO mode, Pin 22 becomes an output pin, and outputs a logic low if a SD video input is detected and a logic high if a HD video input is detected, as notification to the MCU. MACROVISION COMPATIBILITY The on-chip sync processor of the LMH1251 is fully compatible with DVD video sources which are embedded with Macrovision copyright protection. The LMH1251 will output Horizontal Sync pulses with consistent periodicity even during the “Macrovision Sync” pulse period. POWER SAVE MODE The LMH1251 is equipped with a power saving mode which is controlled by Pin 21. This pin is a logic level input. The device will enter a low power mode when the power save pin is applied with a logic high by the MCU. Under these conditions, the IC reduces its current consumption to a minimum as specified in the Electrical Characteristics section. However, the sync processor and switch will always remain active. During power save mode, the RGB video outputs are held to the blank level, while the sync signals are allowed to continue to be processed and/or passed through. Based on the absence or presence of sync signals at the output of the LMH1251, the MCU can determine whether to bring the system to a low power consumption state. OUTPUT DRIVE CHARACTERISTICS The LMH1251 is designed to interface with an ADC or preamplifier through an AC coupling capacitor as shown below in Figure 1. The RGB outputs of the LMH1251 are 700 mVPP video signals with the black level at approximately 2V, which is the chip’s internal voltage reference level. The H Sync and V Sync outputs are CMOS logic outputs that swing from 0 to 5V. These RGBHV outputs do not have any current drive capability and should not have any load on them. The PCB trace length at the output should be kept as short as possible to minimize resisitive and capacitive loading. If the LMH1251 is to be designed into a stand-alone converter box application, the configuration in Figure 2 is recommended. The LMH6739, triple op amp with an internally set gain of 2, can be used to drive RGB video over the VGA cable out to a display monitor. Logic inverters are used for driving the sync signals over the VGA cable. 7 www.national.com LMH1251 Application Notes (Continued) 20151908 FIGURE 1. Typical LMH1251 Application 20151907 FIGURE 2. Simplified Application Diagram for Driving a VGA Cable LAYOUT CONSIDERATIONS The most important point to note regarding the layout of the LMH1251 on a PCB is that the trace length between the output pins of the LMH1251 and the input AC coupling capacitors of the next stage ADC or preamplifier must be as minimal as possible. The trace lengths of the H Sync and V Sync outputs should also be minimized, as the capacitive loading on these outputs must not exceed 6 pF. For long signal paths leading up to the input of the LMH1251, controlled impedance lines should be used, along with impedance matching elements. Bypass capacitors should be placed as close as possible to the supply pins of the device. The larger electrolytic bypass capacitor can be located farther from the device. The 10K external resistor should also be placed as close as possible to the REXT pin. www.national.com 8 LMH1251 Test Circuit 20151928 FIGURE 3. Test Circuit 9 www.national.com LMH1251 YPBPR to RGB Decoder and 2:1 Video Switch Physical Dimensions unless otherwise noted inches (millimeters) 24-Pin TSSOP NS Package Number MTC24 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. 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