CLC006 Serial Digital Cable Driver with Adjustable Outputs General Description Applications National’s Comlinear CLC006 is a monolithic, high-speed cable driver designed for the SMPTE 259M serial digital video data transmission standard. The CLC006 drives 75Ω transmission lines (Belden 8281 or equivalent) at data rates up to 400 Mbps. Controlled output rise and fall times (650 ps typical) minimize transition-induced jitter. The output voltage swing, typically 1.65V, set by an accurate, low-drift internal bandgap reference, delivers an 800 mV swing to backmatched and terminated 75Ω cable. Output swing is adjustable from 0.7 VP-P to 2 VP-P using external resistors. The CLC006’s class AB output stage consumes less power than other designs, 185 mW with both outputs terminated, and requires no external bias resistors. The differential inputs accept a wide range of digital signals from 200 mVP-P to ECL levels within the specified common-mode limits. All this make the CLC006 an excellent general purpose high speed driver for digital applications. The CLC006 is powered from a single +5V or −5.2V supply and comes in an 8-pin SOIC package. ■ ■ ■ ■ Digital routers and distribution amplifiers Coaxial cable driver for digital transmission line Twisted pair driver Serial digital video interfaces for the commercial and broadcast industry ■ SMPTE, Sonet/SDH, and ATM compatible driver ■ Buffer applications 270 Mbps Eye Pattern Key Specifications ■ ■ ■ ■ 650 ps rise and fall times Data rates to 400 Mbps 200 mV differential input Low residual jitter (25 pspp) 10008401 Features ■ ■ ■ ■ ■ ■ No external pull-down resistors Adjustable output amplitude Differential input and output Low power dissipation Single +5V or −5.2V supply Replaces GS9008 in most applications Connection Diagram (8-Pin SOIC) 10008403 Order Number CLC006BM See NS Package Number M08A © 2007 National Semiconductor Corporation 100084 www.national.com CLC006 Serial Digital Cable Driver with Adjustable Outputs October 2007 CLC006 Typical Application 10008402 www.national.com 2 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Output Current Maximum Junction Temperature Storage Temperature Range Lead Temperature (Soldering 10 Seconds) 6V 30 mA +125°C −65°C to +150°C 1000V +160°C/W +105°C/W 254 Mhr Recommended Operating Conditions Supply Voltage Range (VCC – VEE) +300°C +4.5V to +5.5V Electrical Characteristics (VCC = 0V, VEE = −5V; unless otherwise specified). Condition Typ +25°C Min/Max +25°C Min/Max 0°C to +70°C Min/Max −40°C to +85°C Units Supply Current, Loaded 150Ω @ 270 Mbps (Note 5) 37 — — — mA Supply Current, Unloaded (Note 3) 34 28/45 26/47 26/47 mA Output HIGH Voltage (VOH) (Note 3) −1.7 −2.0/1.4 −2.0/1.4 −2.0/1.4 V Output LOW Voltage (VOL) (Note 3) −3.3 −3.6/3.0 −3.6/3.0 −3.6/3.0 V 10 30 50 50 μA Output Swing REXT = ∞(Note 3) 1.65 1.55/1.75 1.53/1.77 1.51/1.79 V Output Swing REXT = 10 kΩ 1.30 — — — V Common Mode Input Range Upper Limit −0.7 −0.8 −0.8 −0.8 V Common Mode Input Range Lower Limit −2.6 −2.5 −2.5 –2.5 V Minimum Differential Input Swing 200 200 200 200 mV Power Supply Rejection Ratio (Note 3) 26 20 20 20 dB 650 425/825 400/850 400/850 ps Parameter STATIC DC PERFORMANCE Input Bias Current AC PERFORMANCE Output Rise and Fall Time (Notes 3, 4, 5) Overshoot 5 % Propagation Delay 1.0 ns Duty Cycle Distortion 50 Residual Jitter 25 ps — — — pspp MISCELLANEOUS PERFORMANCE Input Capacitance 1.0 pF Output Resistance 10 Output Inductance 6 Ω nH Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices should be operated at these limits. The table of “Electrical Characteristics” specifies conditions of device operation. Note 2: Min/Max ratings are based on product characterization and simulation. Individual parameters are tested as noted. Outgoing quality levels are determined from tested parameters. Note 3: Spec is 100% tested at +25°C Note 4: Measured between the 20% and 80% levels of the waveform. Note 5: Measured with both outputs driving 150Ω, AC coupled at 270 Mbps. 3 www.national.com CLC006 ESD Rating (Human Body Model) Package Thermal Resistance θJA 8–pin SOIC θJC 8–pin SOIC Reliability Information MTTF Absolute Maximum Ratings (Note 1) CLC006 Operation INPUT INTERFACING The CLC006 has high impedance, emitter-follower buffered, differential inputs. Single-ended signals may also be input. Transmission lines supplying input signals must be properly terminated close to the CLC006. Either A.C. or D.C. coupling as in Figure 2 or Figure 3 may be used.Figures 2, 4 and Figure 5 show how Thevenin-equivalent resistor networks are used Load Type to provide input termination and biasing. The input D.C. common-mode voltage range is 0.8V to 2.5V below the positive power supply (VCC). Input signals plus bias should be kept within the specified common-mode range. For an 800 mVP-P input signal, typical input bias levels range from 1.2V to 2.1V below the positive supply. Resistor to VCC (R1) Resistor to VEE (R2) ECL, 50Ω, 5V, VT=2V 82.5Ω 124Ω ECL, 50Ω, 5.2V, VT=2V 80.6Ω 133Ω ECL, 75Ω, 5V, VT=2V 124Ω 187Ω ECL, 75Ω, 5.2V, VT=2V 121Ω 196Ω 800 mVP-P, 50Ω, 5V, VT=1.6V 75.0Ω 154Ω 800 mVP-P, 75Ω, 5V, VT=1.6V 110Ω 232Ω 800 mVP-P, 2.2KΩ, 5Ω, VT=1.6V 3240Ω 6810Ω 10008404 FIGURE 1. Input Stage 10008405 FIGURE 2. AC Coupled Input www.national.com 4 CLC006 10008406 FIGURE 3. DC Coupled Input 10008407 10008408 FIGURE 4. Single Ended 50Ω ECL input FIGURE 5. Differential 50Ω ECL Input OUTPUT INTERFACING The CLC006’s class AB output stage, Figure 6, requires no standing current in the output transistors and therefore requires no biasing or pull-down resistors. Advantages of this arrangement are lower power dissipation and fewer external components. The output may be either D.C. or A.C. coupled to the load. A bandgap voltage reference sets output voltage levels which are compatible with F100K and 10K ECL when correctly terminated. The outputs do not have the same output voltage temperature coefficient as 10K. Therefore, noise margins will be reduced over the full temperature range when driving 10K ECL. Noise margins will not be affected when interfacing to F100K since F100K is fully voltage and temperature compensated. 5 www.national.com CLC006 10008409 FIGURE 6. Output Stage 10008410 FIGURE 7. Differential Input DC Coupled Output OUTPUT AMPLITUDE ADJUSTMENT The high and low output levels of the CLC006 are set by a circuit shown simplified in Figure 8. Output high and low levels may be set independently with external resistor networks connected between REXT-H (pin 3), REXT-L (pin 4) and the power supplies. The resistor networks affect the high and low output levels by changing the internally generated bias voltages, VH and VL. The nominal high and low output levels are VCC−1.7V and VCC−3.3V, respectively, when the pins REXT-H and REXT-L are left unconnected. Though the internal components which determine output voltage levels have accurate ratios, their absolute values may be controlled only within about ±15% of nominal. Even so, without external adjustment, www.national.com output voltages are well controlled. A final design should accommodate the variation in externally set output voltages due to the CLC006’s part-to-part and external component tolerances. Output voltage swing may be reduced with the circuit shown in Figure 9. A single resistance chosen with the aid of the graph, Figure 10, is connected between pins 3 and 4. Output voltage swing may be increased with the circuit of Figure 11. Figure 12 is used to estimate a value for resistor R. Note that both of these circuits and the accompanying graphs assume that the CLC006 is loaded with the standard 150Ω. Be aware 6 sistances used to set output levels when the D.C. loading on the CLC006 differs appreciably from 150Ω. 10008411 FIGURE 8. Equivalent Bias Generation Circuit 10008412 FIGURE 9. Differential Input Reduced Output 7 www.national.com CLC006 that output loading will affect the output swing and the high and low levels. It may be necessary to empirically select re- CLC006 10008413 FIGURE 10. Resistance Pins 3 to 4 vs Output Voltage Reduced Output @ 150Ω Load 10008414 FIGURE 11. Differential Input Increased Output 10008415 FIGURE 12. Resistance Pins 3 to 4 vs Output Voltage Increased Output @ 150Ω Load www.national.com 8 CLC006 OUTPUT RISE AND FALL TIMES Output load capacitance can significantly affect output rise and fall times. The effect of load capacitance, stray or otherwise, may be reduced by placing the output back-match resistor close to the output pin and by minimizing all interconnecting trace lengths. Figure 13 shows the effect on risetime of parallel load capacitance across a 150Ω load. 10008416 FIGURE 13. Rise Time vs CL PCB Layout Recommendations Printed circuit board layout affects the performance of the CLC006. The following guidelines will aid in achieving satisfactory device performance. • Use a ground plane or power/ground plane sandwich design for optimum performance. • Bypass device power with a 0.01 µF monolithic ceramic capacitor in parallel with a 6.8 µF tantalum electrolytic capacitor located no more than 0.1” (2.5 mm) from the device power pins. • Provide short, symmetrical ground return paths for: — inputs, — supply bypass capacitors and — the output load. • Provide short, grounded guard traces located — under the centerline of the package, — 0.1” (2.5 mm) from the package pins — on both top and bottom of the board with connecting vias. 9 www.national.com CLC006 Physical Dimensions inches (millimeters) unless otherwise noted Order Number CLC006BM NS Package Number M08A www.national.com 10 CLC006 Notes 11 www.national.com CLC006 Serial Digital Cable Driver with Adjustable Outputs Notes THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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