CLC020 SMPTE 259M Digital Video Serializer with Integrated Cable Driver General Description Features The CLC020 SMPTE 259M Digital Video Serializer with Integrated Cable Driver is a monolithic integrated circuit that encodes, serializes and transmits bit-parallel digital data conforming to SMPTE 125M and SMPTE 267M component video and SMPTE 244M composite video standards. The CLC020 can also serialize other 8 or 10-bit parallel data. The CLC020 operates at data rates from below 100 Mbps to over 400 Mbps. The serial data clock frequency is internally generated and requires no external frequency setting components, trimming or filtering*. Functions performed by the CLC020 include: parallel-to-serial data conversion, data encoding using the polynomial (X9+X4+1), data format conversion from NRZ to NRZI, parallel data clock frequency multiplication and encoding with the serial data, and coaxial cable driving. Input for sync (TRS) detection disabling and a PLL lock detect output are provided. The CLC020 has an exclusive built-in self-test (BIST) and video test pattern generator (TPG) with 4 component video test patterns, reference black, PLL and EQ pathologicals and modified colour bars, in 4:3 and 16:9 raster and both NTSC and PAL formats*. Separate power pins for the output driver, VCO and the digital logic improve power supply rejection, output jitter and noise performance. n SMPTE 259M serial digital video standard compliant n No external serial data rate setting or VCO filtering components required* n Built-in self-test (BIST) and video test pattern generator (TPG) with 16 internal patterns* n Supports all NTSC and PAL standard component and composite serial video data rates n HCMOS/TTL-compatible data and control inputs and outputs n 75Ω ECL-compatible, differential, serial cable-driver outputs n Fast VCO lock time: < 75 µs n Single +5V TTL or −5V ECL supply operation n Low power: 235 mW typical n 28-lead PLCC package n Commercial temperature range 0˚C to +70˚C The CLC020 is the ideal complement to the CLC011B SMPTE 259M Serial Digital Video Decoder, CLC014 Active Cable Equalizer, CLC016 Data Retiming PLL (clock-data separator), CLC018 8X8 Digital Crosspoint Switch and CLC006 or CLC007 Cable Drivers, for a complete parallelserial-parallel, high-speed data processing and transmission system. The CLC020 is powered from a single 5V supply. Power dissipation is typically 235 mW including two 75Ω backmatched output loads. The device is packaged in a JEDEC 28-lead PLCC. Applications n SMPTE 259M parallel-to-serial digital video interfaces for: — Video cameras — VTRs — Telecines — Video test pattern generators and digital video test equipment n Non-SMPTE video applications n Other high data rate parallel/serial video and data systems * Patents applications made or pending. Typical Application 10091712 © 2003 National Semiconductor Corporation DS100917 www.national.com CLC020 SMPTE 259M Digital Video Serializer with Integrated Cable Driver July 2003 CLC020 Block Diagram 10091701 Connection Diagram 10091702 28-Pin PLCC Order Number CLC020BCQ See NS Package Number V28A www.national.com 2 Junction Temperature (Note 1) Lead Temperature (Soldering 4 Sec) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VDD−VSS) −0.5V to (VDD + 0.5V) CMOS/TTL Output Voltage (VO) −0.5V to (VDD + 0.5V) VI = VSS −0.5V −5 mA +5 mA CMOS/TTL Output Source/Sink Current SDO Output Source Current 33,400 5.0V ± 10% Supply Voltage (VDD−VSS) VSS to VDD PCLK Frequency Range 10 to 40MHz PCLK Duty Cycle 20 mA 45 to 55% DN and PCLK Rise/Fall Time Package Thermal Resistance θJA 28-lead PLCC θJC 28-lead PLCC Storage Temp. Range Transistor Count CMOS/TTL Input Voltage ± 1 mA ± 10 mA Input Current, Other Inputs ESD Rating (MM) Recommended Operating Conditions CMOS/TTL Input Current (single input) VI = VDD +0.5V +260˚C > 2.5 kV > 200 V ESD Rating (HBM) 6.0V CMOS/TTL Input Voltage (VI) +150˚C 1.0 to 3.0 ns 3.0V ± 10% 85˚C/W Maximum DC Bias on SDO pins 35˚C/W Operating Free Air Temperature (TA) 0˚C to +70˚C −65˚C to +150˚C DC Electrical Characteristics Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Notes 2, 3). Symbol Parameter VIH Input Voltage High Level Conditions VIL Input Voltage Low Level IIH Input Current High Level VIH = VDD IIL Input Current Low Level VIL = VSS VOH CMOS Output Voltage High Level IOH = −10 mA VOL CMOS Output Voltage Low Level IOL = +10 mA VSDO Serial Driver Output Voltage RL = 75Ω 1%, RREF = 1.69 kΩ 1%, Figure 2 IDD Power Supply Current, Total RL = 75Ω 1%, RREF = 1.69 kΩ 1%, PCLK = 27 MHz, Figure 2, NTSC Colour Bar Pattern Reference Min D0 through D9, PCLK, TPG_EN and Sync. Detect Enable 2.0 VDD V VSS 0.8 V +40 +60 µA -1 -20 µA 2.4 4.7 VDD V 0.0 0.3 VSS + 0.5V V 700 800 900 mVP-P 47 60 mA Lock Detect, Test Out SDO, SDO Typ Max Units AC Electrical Characteristics Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3). Symbol Parameter Conditions Reference Min Max Units BRSDO Serial data rate RL = 75Ω, AC coupled, (Note 5) SDO, SDO 100 400 Mbps FPCLK Reference Clock Input Frequency PCLK 10 40 MHz Reference Clock Duty Cycle PCLK 45 50 55 % DN, PCLK 1.0 1.5 3.0 tr, tf Rise time, Fall time 10%–90% tj Serial output jitter 270 Mbps,Figure 2, (Note 6) tjit Serial output jitter (Notes 4, 5) tr, tf Rise time, Fall time 20%–80%, (Notes 4, 5) Lock time 270 Mbps, (Notes 5, 7) tSU Setup time Figure 3 SDO, SDO DN to PCLK 3 ns 220 500 Output overshoot tLOCK Typ 3 psP-P 100 200 psP-P 800 1500 ps 1 % 75 µs 2 ns www.national.com CLC020 Absolute Maximum Ratings CLC020 AC Electrical Characteristics (Continued) Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3). Symbol Parameter Conditions Reference Min Typ tHLD Hold time Figure 3 DN from PCLK 1.5 1 ns LGEN Output inductance (Note 4) 6 nH RGEN Output resistance (Note 4) 25k Ω SDO, SDO Max Units Note 1: “Absolute Maximum Ratings” are those parameter values beyond which the life and operation of the device cannot be guaranteed. The stating herein of these maximums shall not be construed to imply that the device can or should be operated at or beyond these values. The table of “Electrical Characteristics” specifies acceptable device operating conditions. Note 2: Current flow into device pins is defined as positive. Current flow out of device pins is defined as negative. All voltages are stated referenced to VSS = 0V. Note 3: Typical values are stated for VDD = +5.0V and TA = +25˚C. Note 4: Specification is guaranteed by design. Note 5: RL = 75Ω, AC-coupled @ 270 Mbps, RREF = 1.69 kΩ 1%, See Test Loads and Figure 2. Note 6: CLC020 mounted in the SD020EVK board, configured in BIST mode (NTSC color bars) with PCLK = 27MHz derived from Tektronix TG2000 black-burst reference. Timing jitter measured with Tektronix VM700T using jitter measurement FFT mode, frame rate, 1kHz filter bandwidth, Hanning window. Note 7: Measured from rising-edge of first PCLK cycle until Lock Detect output goes high (true). Test Loads 10091703 All resistors in Ohms, 1% tolerance. FIGURE 1. Test Loads www.national.com 4 CLC020 Test Loads (Continued) 10091704 FIGURE 2. Test Circuit Timing Diagram 10091705 FIGURE 3. Setup and Hold Timing 5 www.national.com CLC020 PHASE-LOCKED LOOP AND VCO The phase-locked loop (PLL) system generates the output serial data clock at 10x the parallel data clock frequency. This system consists of a VCO, divider chain, phasefrequency detector and internal loop filter. The VCO freerunning frequency is internally set. The PLL automatically generates the appropriate frequency for the serial clock rate using the parallel data clock (PCLK) frequency as its reference. Loop filtering is internal to the CLC020. The VCO has separate VSSO and VDDO power supply feeds, pins 15 and 16, which may be supplied power independently via an external low-pass filter, if desired. The PLL acquisition (lock) time is less than 75 µs @ 270 Mbps. Device Operation The CLC020 SMPTE 259M Digital Video Serializer is used in digital video signal origination and processing equipment: cameras, video tape recorders, telecines, video test equipment and others. It converts parallel component or composite digital video signals into serial format. Logic levels within this equipment are normally TTL-compatible as produced by CMOS or bipolar logic devices. The encoder outputs ECLcompatible serial digital video (SDV) signals conforming to SMPTE 259M-1997. The CLC020 operates at all standard SMPTE and ITU-R parallel data rates. VIDEO DATA PROCESSING CIRCUITS The input data register accepts 8 or 10-bit parallel data and clock signals having CMOS/TTL-compatible signal levels. Parallel data may conform to any of several standards: SMPTE 125M, SMPTE 267M, SMPTE 244M or ITU-R BT.601. If data is 8-bit, it is converted to a 10-bit representation according to the type of data being input: component 4:2:2 per SMPTE 259M paragraph 7.1.1, composite NTSC per paragraph 8.1.1 or composite PAL per paragraph 9.1.1. Output from this register feeds the SMPTE polynomial generator/serializer and sync detector. All CMOS inputs including the PCLK input have internal pull-down devices. The sync detector or TRS character detector accepts data from the input register. The detection function is controlled by Sync Detect Enable, a low-true, TTL-compatible, external signal. Synchronization words, the timing reference signals (TRS), start-of-active-video (SAV) and end-of-active-video (EAV) are defined in SMPTE 125M-1995 and 244M. The sync detector supplies control signals to the SMPTE polynomial generator that identify the presence of valid video data. The sync detector performs input TRS character LSBclipping as prescribed in ITU-R-BT.601. LSB-clipping causes all TRS characters with a value between 000h and 003h to be forced to 000h and all TRS characters with a value between 3FCh and 3FFh to be forced to 3FFh. Clipping is done prior to encoding. The SMPTE polynomial generator accepts the parallel video data and encodes it using the polynomial X9+X4+1 as specified in SMPTE 259M–1997, paragraph 5 and Annex C. The scrambled data is then serialized for output. The NRZ-to-NRZI converter accepts serial NRZ data from the SMPTE polynomial genertor and converts it to NRZI using the polynomial X + 1 per SMPTE 259M–1997, paragraph 5.2 and Annex C. The transmission bit order is LSB first, per paragraph 6. The converter’s output feeds the output driver amplifier. LOCK DETECT The Lock Detect output of the phase-frequency detector indicates the PLL lock condition. It is a logic HIGH when the loop is locked. The output is CMOS/TTL-compatible and is suitable for driving other CMOS devices or a LED indicator. SERIAL DATA OUTPUT BUFFER The current-mode serial data outputs provide low-skew complimentary or differential signals. The output buffer design can drive 75Ω coaxial cables (AC-coupled) or 10k/100k ECL/PECL-compatible devices (DC-coupled). Output levels are 800 mVP-P ± 10% into 75Ω AC-coupled, back-matched loads. The output level is 400 mVP-P ± 10% when DCcoupled into 75Ω (See Application Information for details). The 75Ω resistors connected to the SDO outputs are backmatching resistors. No series back-matching resistors should be used. SDO output levels are controlled by the value of RREF connected to pin 19. The value of RREF is normally 1.69 kΩ, ± 1%. The output buffer is static when the device is in an out-of-lock condition. Separate VSSSD and VDDSD power feeds, pins 21 and 24, are provided for the serial output driver. POWER-ON RESET The CLC020 has an internally controlled, automatic, power-on reset circuit. This circuit clears TRS detection circuitry, all latches, registers, counters and polynomial generators and disables the serial output. The SDO outputs are tri-stated during power-on reset. The part will remain in the reset condition until the parallel input clock is applied. It is recommended that PCLK not be asserted until at least 30 µs after power has reached VDDmin. See Figure 4. 10091714 FIGURE 4. Power-On Reset Sequence www.national.com 6 produced. The test patterns are: flat-field black, PLL pathological, equalizer (EQ) pathological and a modified 75%, 8-color vertical bar pattern. The pathologicals follow recommendations contained in SMPTE RP 178–1996 regarding the test data used. The color bar pattern does not incorporate bandwidth limiting coding in the chroma and luma data when transitioning between the bars. For this reason, it may not be suitable for use as a visual test pattern or for input to video D-to-A conversion devices unless measures are taken to restrict the production of out-of-band frequency components. (Continued) BUILT-IN SELF-TEST (BIST) The CLC020 has a built-in self-test (BIST) function. The BIST performs a comprehensive go-no-go test of the device. The test uses either a full-field color bar for NTSC or a PLL pathological for PAL as the test data pattern. Data is input internally to the input data register, processed through the device and tested for errors. Table 1 gives device pin functions and Table 2 gives the test pattern codes used for this function. The signal level at Test_Output, pin 26, indicates a pass or fail condition. The TPG is operated by applying the code for the desired test pattern to D0 through D3 (D4 through D9 are 00h). Since all parallel data inputs are equipped with an internal pulldown device, only those inputs D0 through D3 which require a logic-1 need be pulled high. Next, apply a 27 or 36 MHz signal, appropriate to the raster size desired, at the PCLK input and wait until the Lock_Detect output goes true indicating the VCO is locked on-frequency. Then, take TPG_Enable, pin 17, to a logic high. The serial test pattern data appears on the SDO outputs. TPG_Enable may be temporarily connected to the Lock_Detect output to automate TPG operation. The TPG mode is exited by taking TPG_Enable to a logic low. Table 1 gives device pin functions for this mode. Table 2 gives the available test patterns and selection codes. The BIST is initiated by applying the code for the desired BIST to D0 throught D3 (D9 through D4 are 00h) and a 27 MHz clock at the PCLK input. Since all parallel data inputs are equipped with an internal pull-down device, only those inputs D0 through D3 which require a logic-1 need be pulled high. After the Lock_Detect output goes high (true) indicating the VCO is locked on frequency, TPG_Enable, pin 17, is then taken to a logic high. TPG_Enable may be temporarily connected to the Lock_Detect output to automate BIST operation. Test_Output, pin 26, is monitored for a pass/fail indication. If no errors have been detected, this output will go to a logic high level approximately 2 field intervals after TPG_Enable is taken high. If errors have been detected in the internal circuitry of the CLC020, Test_Output will remain low until the test is terminated. The BIST is terminated by taking TPG_Enable to a logic low. Continuous serial data output is available during the test. TEST PATTERN GENERATOR The CLC020 features an on-board test pattern generator (TPG). Four full-field component video test patterns for both NTSC and PAL standards, and 4x3 and 16x9 raster sizes are 10091706 FIGURE 5. Built-In Self-Test Control Sequence 7 www.national.com CLC020 Device Operation CLC020 Device Operation (Continued) 10091707 FIGURE 6. Test Pattern Generator Control Sequence TABLE 1. BIST and Test Pattern Generator Control Functions Pin Name 3 D0 TPG code input LSB Function 4 D1 TPG code input 5 D2 TPG code input 6 D3 TPG code input MSB 17 TPG_EN TPG Enable, active high true 26 Test_Out BIST Pass/Fail output. Pass=High (See text for timing requirements) TABLE 2. Component Video Test Pattern Selection Standard Frame D3 D2 D1 D0 NTSC 4x3 Flat-field black Test Pattern 0 0 0 0 NTSC 4x3 PLL pathological 0 0 0 1 NTSC 4x3 EQ pathological 0 0 1 0 NTSC 4x3 Color bars, 75%, 8-bars (modified, see text), BIST 0 0 1 1 PAL 4x3 Flat-field black 0 1 0 0 PAL 4x3 PLL pathological, BIST 0 1 0 1 PAL 4x3 EQ pathological 0 1 1 0 PAL 4x3 Color bars, 75%, 8-bars (modified, see text) 0 1 1 1 NTSC 16x9 Flat-field black 1 0 0 0 NTSC 16x9 PLL pathological 1 0 0 1 NTSC 16x9 EQ pathological 1 0 1 0 NTSC 16x9 Color bars, 75%, 8-bars (modified, see text) 1 0 1 1 PAL 16x9 Flat-field black 1 1 0 0 PAL 16x9 PLL pathological 1 1 0 1 PAL 16x9 EQ pathological 1 1 1 0 PAL 16x9 Color bars, 75%, 8-bars (modified, see text) 1 1 1 1 Note: D9 through D4 = 0 (binary) www.national.com 8 CLC020 Pin Descriptions Pin # Name Description Positive power supply input (digital logic) 1 VDD 2 VDD Positive power supply input (digital logic) 3 D0 Parallel data input/Test pattern select (LSB) 4 D1 Parallel data input/Test pattern select 5 D2 Parallel data input/Test pattern select 6 D3 Parallel data input/Test pattern select (MSB) 7 D4 Parallel data input 8 D5 Parallel data input 9 D6 Parallel data input 10 D7 Parallel data input 11 D8 Parallel data input 12 D9 Parallel data input 13 PCLK Parallel clock input 14 Lock Detect VCO Lock Detect output (high-true) 15 VSSO Negative power supply input (PLL supply) 16 VDDO Positive power supply input (PLL supply) 17 TPG_EN Test Pattern Generator (TPG) Enable input (high-true) 18 VSSOD Negative power supply input (PLL digital supply) 19 RREF Output driver level control 20 VDDOD Positive power supply input (PLL digital supply) 21 VSSSD Negative power supply input (Output driver) 22 SDO Serial data true output 23 SDO Serial data complement output 24 VDDSD Positive power supply input (Output driver) 25 Sync Detect Enable Parallel data sync detection enable input (low true) 26 Test_Out BIST Pass/Fail output 27 VSS Negative power supply input (digital logic) 28 VSS Negative power supply input (digital logic) Note: All CMOS/TTL inputs have internal pull-down devices. 9 www.national.com CLC020 SD020EVK. The board may be ordered through any of National’s sales offices. Complete circuit board layouts and schematics, for the SD020EVK are available on National’s WEB site in the application information for this device. For latest information, please see: www.national.com/appinfo/ interface Application Information A typical application circuit for the CLC020 is shown in Figure 7. This circuit demonstrates the capabilities of the CLC020 and allows its evaluation in a variety of configurations. An assembled demonstration board with more comprehensive evaluation options is available, part number APPLICATION CIRCUIT 10091708 FIGURE 7. Typical Application Circuit Several different input and output drive and loading options can be constructed on the SD020EVK application circuit board, Figure 8. Pin headers are provided for input cabling and control signal access. The appropriate value resistor packs, 220 and 330Ω for TTL or 50Ω for signal sources requiring such loading, should be installed at RP1-4 before applying input signals. The board’s outputs may be DC interfaced to PECL inputs by first installing 124Ω resistors at R1B and R2B, changing R1A and R2A to 187Ω and replacing C1 and C2 with short circuits. The PECL inputs should be directly connected to J1 and J2 without cabling. If 75Ω cabling is used to connect the CLC020 to the PECL inputs, the voltage dividers used on the CLC020 outputs must be removed and re-installed on the circuit board where the PECL device is mounted. This will www.national.com provide correct termination for the cable and biasing for both the CLC020’s outputs and the PECL inputs. It is most important to note that a 75Ω or equivalent DC loading (measured with respect to the negative supply rail) must always be installed at both of the CLC020’s SDO outputs to obtain proper signal levels from device. When using 75Ω Theveninequivalent load circuits, the DC bias applied to the SDO outputs should not exceed +3V with respect to the negative supply rail. Serial output levels should be reduced to 400 mVp-p by changing RREF to 3.4 kΩ. The Test Out output is intended for monitoring by equipment presenting high impedance loading ( > 500Ω). When monitoring the Lock Detect output, the attached monitoring circuit should present a DC resistance greater than 5 kΩ so that Lock Detect indicator operation is not affected. 10 CLC020 Application Information (Continued) 10091709 Connect LOCK DETECT to TPG ENABLE for test pattern generator function. Remove RP1 & RP3 and replace RP2 & RP4 with 50Ω resistor packs for coax interfacing. Install RP1-4 when using ribbon cable for input interfacing. This board is designed for use with TTL power supplies only. For optional ECL compatible load: R1A = R2A = 187; R1B = R2B = 124. All resistances & impedances in Ohms. Values with 3 significant digits are 1%; with 2 digits 5%. FIGURE 8. SD020EVK Schematic Diagram MEASURING JITTER The test method used to obtain the timing jitter value given in the AC Electrical Specification table is based on procedures and equipment described in SMPTE RP 192-1996. The recommended practice discusses several methods and indicator devices. An FFT method performed by standard video test equipment was used to obtain the data given in this data sheet. As such, the jitter characteristics (or jitter floor) of the measurement equipment, particularly the measurement analyzer, become integral to the resulting jitter value. The method and equipment were chosen so that the test can be easily duplicated by the design engineer using most standard digital video test equipment. In so doing, similar results should be achieved. The intrinsic jitter floor of the CLC020’s PLL is approximately 25% of the typical jitter given in the electrical specifications. In production, device jitter is measured on automatic IC test equipment (ATE) using a different method compatible with that equipment. Jitter measured using this ATE yields values approximately 50% of those obtained using the video test equipment. The jitter test setup used to obtain values quoted in the data sheet consists of: • National Semiconductor SD020EVK, CLC020 evaluation kit • Tektronix TG2000 signal generation platform with DVG1 option • Tektronix VM700T Option 1S Video Measurement Set • Tektronix TDS 794D, Option C2 oscilloscope • Tektronix P6339A passive probe • 75 Ohm coaxial cable, 3ft., Belden 8281 or RG59 (2 required) • ECL-to-TTL/CMOS level converter/amplifier, Figure 10 Apply the black-burst reference clock from the TG2000 signal generator’s BG1 module 27MHz clock output to the level converter input. The clock amplitude converter schematic is shown in Figure 9. Adjust the input bias control to give a 50% duty cycle output as measured on the oscilloscope/probe system. Connect the level translator to the SD020EVK board, connector P1, PCLK pins (the outer-most row of pins 11 www.national.com CLC020 Application Information The VM700T measurement system’s jitter floor specification at 270Mbps is given as 200ps ± 20% (100ps ± 5% typical) of actual components from 50Hz to 1MHz and 200ps +60%, -30% of actual components from 1MHz to 10MHz. To obtain the actual residual jitter of the CLC020, a root-sum-square adjustment of the jitter reading must be made to compensate for the measurement system’s jitter floor specification. For example, if the jitter reading is 250ps, the CLC020 residual jitter is the square root of (2502 − 2002) = 150ps. The accuracy limits of the reading as given above apply. (Continued) is ground). Configure the SD020EVK to operate in the NTSC colour bars, BIST mode. Configure the VM700T to make the jitter measurement in the jitter FFT mode at the frame rate with 1kHz filter bandwidth and Hanning window. Configure the setup as shown in Figure 9. Switch the test equipment on (from standby mode) and allow all equipment temperatures stabilize per manufacturer’s recommendation. Measure the jitter value after allowing the instrument’s reading to stabilize (about 1 minute). Consult the VM700T Video Measurement Set Option 1S Serial Digital Measurements User Manual (document number 071-0074-00) for details of equipment operation. 10091710 FIGURE 9. Jitter Test Circuit 10091713 FIGURE 10. ECL-to-TTL/CMOS level converter/amplifer www.national.com 12 CLC020 Application Information (Continued) 10091711 FIGURE 11. Jitter Plots viding short paths for image currents which reduces signal distortion. The planes should be pulled back from all transmission lines and component mounting pads a distance equal to the width of the widest transmission line or the thickness of the dielectric separating the transmission line from the internal power or ground plane(s) whichever is greater. Doing so minimizes effects on transmission line impedances and reduces unwanted parasitic capacitances at component mounting pads. In especially noisy power supply environments, such as is often the case when using switching power supplies, separate filtering may be used at the CLC020’s VCO and output driver power pins. The CLC020 was designed for this situation. The digital section, VCO and output driver power supply feeds are independent (see pinout description table and pinout drawing for details). Supply filtering may take the form of L-section or pi-section, L-C filters in series with these VDD inputs. Such filters are available in a single package from several manufacturers. Despite being independent feeds, all device power supplies should be applied simultaneously as from a common source. The CLC020 is free from power supply latch-up caused by circuit-induced delays between the device’s three separate power feed systems. PCB LAYOUT AND POWER SYSTEM BYPASS RECOMMENDATIONS Circuit board layout and stack-up for the CLC020 should be designed to provide noise-free power to the device. Good layout practice also will separate high frequency or high level inputs and outputs to minimize unwanted stray noise pickup, feedback and interference. Power system performance may be greatly improved by using thin dielectrics (4 to 10 mils) for power/ground sandwiches. This increases the intrinsic capacitance of the PCB power system which improves power supply filtering, especially at high frequencies, and makes the value and placement of external bypass capacitors less critical. External bypass capacitors should include both RF ceramic and tantalum electrolytic types. RF capacitors may use values in the range 0.01 µF to 0.1 µF. Tantalum capacitors may be in the range 2.2 µF to 10 µF. Voltage rating for tantalum capacitors should be at least 5x the power supply voltage being used. It is recommended practice to use two vias at each power pin of the CLC020 as well as all RF bypass capacitor terminals. Dual vias reduce the interconnect inductance by up to half, thereby reducing interconnect inductance and extending the effective frequency range of the bypass components. The outer layers of the PCB may be flooded with additional VSS (ground) plane. These planes will improve shielding and isolation as well as increase the intrinsic capacitance of the power supply plane system. Naturally, to be effective, these planes must be tied to the VSS power supply plane at frequent intervals with vias. Frequent via placement also improves signal integrity on signal transmission lines by pro- REPLACING THE GENNUM GS9022 The CLC020 is form-fit-function compatible with the Gennum GS9022. The CLC020 can improve the performance of GS9022 applications using the existing PCB layout with the removal of certain components or changes to component 13 www.national.com CLC020 Application Information The CLC020 has current-mode serial cable driver outputs. These outputs have very high internal generator resistance as one would expect of a current source. Though these current-mode outputs can produce the equivalent drive voltages into the load, it is necessary to change and simplify the typical GS9022 output circuit normally recommended for that device. The output load resistors at pins 22 and 23 must be changed to 75Ω, 1% values. These resistors become the back-matching loads across which the CLC020’s outputs develop drive voltage. The series back-matching resistors used on the GS9022 should be removed and replaced with short circuits. The risetime compensating capacitors across these resistors should be removed. Pin 28 on the CLC020 is VSS and must be connected to the negative supply or ground. On layouts designed to mount the GS9022, the series R-C network connected to this pin should be replaced by short circuits (0Ω resistors). The pull-up resistor connected to the Lock Detect output, pin 14, should be removed. It may be replaced by a LED and current limiting resistor connected to VSS if a visual lock indicator is desired. (Continued) values. New layouts using the CLC020 will benefit from the greatly reduced ancilliary component count and more compact layout. The CLC020 does not require external VCO filtering components. The external VCO filtering components at pin 17 of the GS9022 may remain connected to the CLC020 without complications. It is suggested that these be removed from the circuit board. The CLC020 uses pin 17 for its test pattern generator enable function. You will find the TPG function very useful when you make this change. Remove the COSC capacitor used by the GS9022 at pin 26. The CLC020 uses pin 26 as the BIST pass/fail indicator output. You may attach a LED as an indicator to this pin, if desired. LED current should be limited to 10 mA maximum. The same LED type and current limiting resistor shown in Figure 8 at the Lock Detect output may be used for this indicator function. Remove any capacitor attached to pin 19. A capacitor attached to pin 19 will cause distortion of the output VOH level. The former data rate setting resistor, RVCO, at pin 19 now functions as the output level setting resistor, RREF. It must be changed to a 1.69 kΩ, 1% value for correct output level setting. The input series resistors and the PCLK risetime filter capacitor used with the GS9022 are not needed for the CLC020. These components should be removed from the circuit board and the resistors replaced by short circuits (0Ω resistors). These series resistors will increase input signal rise and fall times if left on the board. www.national.com The CLC020 has an internal pull-down at the Sync Detect Enable input and may be left unconnected in SMPTE videoonly applications. The CLC020 has independent power supply pins for the VCO, VSSO, pin 15 and VDDO, pin 16. The CLC020 has an output driver negative supply, VSSSD, at pin 21. The output driver positive supply, VDDSD, is pin 24 (as on the GS9022). On new layouts, additional power supply filtering may be added at these pins, if desired. 14 inches (millimeters) unless otherwise noted 28-Pin PLCC Order Number CLC020BCQ NS Package Number V28A 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. 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 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 to the user. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 2. A critical component is 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. National Semiconductor Asia Pacific Customer Support Center Email: [email protected] National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560 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. CLC020 SMPTE 259M Digital Video Serializer with Integrated Cable Driver Physical Dimensions