LMH0074

LMH0074 SMPTE 259M / 344M Adaptive Cable Equalizer August 27, 2009 LMH0074 SMPTE 259M / 344M Adaptive Cable Equalizer General Description The LMH0074 SMPTE 259M / 344M Adaptive Cable Equalizer is designed to equalize data transmitted over cable (or any media with similar dispersive loss characteristics). The equalizer operates over a wide range of data rates from 125 Mbps to 540 Mbps and supports SMPTE 259M and SMPTE 344M. The LMH0074 implements DC restoration to correctly handle pathological data conditions. The equalizer may be driven in either a single ended or differential configuration. Additional features include separate carrier detect and output mute pins which may be tied together to mute the output when no signal is present. A programmable mute reference is provided to mute the output at a selectable level of signal degradation. Features ■ ■ ■ ■ ■ SMPTE 259M and SMPTE 344M compliant Supports DVB-ASI at 270 Mbps Data rates: 125 Mbps to 540 Mbps Equalizes up to 400 meters of Belden 1694A at 270 Mbps Manual bypass and output mute with a programmable threshold ■ Single-ended or differential input ■ 50Ω differential outputs ■ Single 3.3V supply operation ■ Industrial temperature range: −40°C to +85°C ■ 208mW typical power consumption with 3.3V supply ■ Footprint compatible with the LMH0044 and the GS9074A Applications ■ SMPTE 259M and SMPTE 344M serial digital interfaces ■ Serial digital data equalization and reception ■ Data recovery equalization Typical Application 30027501 © 2009 National Semiconductor Corporation 300275 www.national.com LMH0074 Absolute Maximum Ratings (Note 1) Supply Voltage Input Voltage (all inputs) Storage Temperature Range Junction Temperature Lead Temperature (Soldering 4 Sec) Package Thermal Resistance  θJA 16-pin LLP  θJC 16-pin LLP ESD Rating (HBM) ESD Rating (MM) −0.5V to 3.6V −0.3V to VCC+0.3V −65°C to +150°C +150°C +260°C +43°C/W +9°C/W 8kV 250V Recommended Operating Conditions Supply Voltage (VCC – VEE) Input Coupling Capacitance AEC Capacitor (Connected between AEC+ and AEC-) Operating Free Air Temperature (TA) 3.3V ±5% 1.0 µF 1.0 µF −40°C to +85°C DC Electrical Characteristics Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Notes 2, 3). Symbol Parameter VCMIN VSDI VCMOUT VSDO Input Common Mode Voltage Input Voltage Swing Output Common Mode Voltage Output Voltage Swing MUTEREF DC Voltage (floating) MUTEREF Range CD Output Voltage MUTE Input Voltage ICC Supply Current Carrier not present Carrier present Min to mute outputs Max to force outputs active (Note 7) 63 MUTE 3.0 0.8 77 CD 2.6 0.4 50Ω load, differential MUTEREF At LMH0074 input, (Notes 4, 6) SDO, SDO Conditions Reference SDI, SDI 720 Min Typ 1.9 800 VCC – VSDO/2 750 1.3 0.7 950 Max Units V mVP−P V mVP-P V V V V V V mA www.national.com 2 LMH0074 AC Electrical Characteristics Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3). Symbol Parameter BRMIN BRMAX Minimum Input Data Rate Maximum Input Data Rate Jitter for various Cable Lengths (with equalizer pathological) 270 Mbps, Belden 1694A, 400 meters (Note 4) 270 Mbps, Belden 8281, 280 meters (Note 4) tr,tf tOS ROUT RLIN RIN CIN Output Rise Time, Fall Time Mismatch in Rise/Fall Time Output Overshoot Output Resistance Input Return Loss Input Resistance Input Capacitance 20% – 80%, (Note 4) (Note 4) (Note 4) single-ended, (Note 5) (Note 8) single-ended single-ended, (Note 5) SDI, SDI 15 SDO, SDO 0.2 0.2 100 2 1 50 18-20 1.3 1 220 15 5 Conditions Reference SDI, SDI Min Typ 125 540 Max Units Mbps Mbps UI UI ps ps % Ω dB kΩ pF 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 VEE = 0 Volts. Note 3: Typical values are stated for VCC = +3.3V and TA = +25°C. Note 4: Specification is guaranteed by characterization. Note 5: Specification is guaranteed by design. Note 6: The maximum input voltage swing assumes a nonstressing, DC-balance signal; specifically, the SMPTE-recommended color bar test signal. Pathological or other stressing signals may not be used. This specification is for 0m cable only. Note 7: Supply current depends on the amount of cable being equalized. The current is highest for short cable and decreases as the cable length is increased. Refer to Figure 1. Note 8: Input return loss is dependent on board design. The LMH0074 meets this specification on the SD074 evaluation board from 5MHz to 1.5GHz. 3 www.national.com LMH0074 Connection Diagram 30027503 16-Pin LLP Order Number LMH0074SQ See NS Package Number SQB16A Pin Descriptions Pin # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 VEE SDI SDI VEE AEC+ AECBYPASS MUTEREF VEE SDO SDO VEE VCC MUTE Name Description Negative power supply (ground). Serial data true input. Serial data complement input. Negative power supply (ground). AEC loop filter external capacitor (1µF) positive connection. AEC loop filter external capacitor (1µF) negative connection. Bypasses equalization and DC restoration when high. No equalization occurs in this mode. Mute reference. Sets the threshold for CD and (with CD tied to MUTE) determines the maximum cable to be equalized before muting. MUTEREF may be unconnected for maximum equalization. Negative power supply (ground). Serial data complement output. Serial data true output. Negative power supply (ground). Positive power supply (+3.3V). Output mute. To disable the mute function and enable the output, MUTE must be tied to GND or a low level signal. To force the outputs to a muted state, tie to VCC. CD may be tied to this pin to inhibit the output when no input signal is present. MUTE has no function in BYPASS mode. Carrier detect. CD is high when no signal is present. CD has no function in BYPASS mode. Positive power supply (+3.3V). Connect exposed DAP to negative power supply. 15 16 DAP CD VCC VEE www.national.com 4 LMH0074 Block Diagram 30027502 Device Operation BLOCK DESCRIPTION The Equalizer Filter block is a multi-stage adaptive filter. If Bypass is high, the equalizer filter is disabled. The DC Restoration / Level Control block receives the differential signals from the equalizer filter block. This block incorporates a self-biasing DC restoration circuit to fully DC restore the signals. If Bypass is high, this function is disabled. The signals before and after the DC Restoration / Level Control block are used to generate the Automatic Equalization Control (AEC) signal. This control signal sets the gain and bandwidth of the equalizer filter. The loop response in the AEC block is controlled by an external 1µF capacitor placed across the AEC+ and AEC- pins. The Carrier Detect / Mute block generates the carrier detect signal and controls the mute function of the output. This block utilizes the CD and MUTE signals along with Mute Reference (MUTEREF). The Output Driver produces SDO and SDO. MUTE REFERENCE (MUTEREF) The mute reference sets the threshold for CD and (with CD tied to MUTE) determines the amount of cable to equalize before automatically muting the outputs. This is set by applying a voltage inversely proportional to the length of cable to equalize. As the applied MUTEREF voltage is increased, the amount of cable that can be equalized before carrier detect is de-asserted and the outputs are muted is decreased. MUTEREF may be left unconnected for maximum equalization before muting. CARRIER DETECT (CD) AND MUTE Carrier detect CD indicates if a valid signal is present at the LMH0074 input. If MUTEREF is used, the carrier detect threshold will be altered accordingly. CD provides a high voltage when no signal is present at the LMH0074 input. CD is low when a valid input signal is detected. MUTE can be used to manually mute or enable SDO and SDO. Applying a high input to MUTE will mute the LMH0074 outputs. Applying a low input will force the outputs to be active. CD and MUTE may be tied together to automatically mute the output when no input signal is present. INPUT INTERFACING The LMH0074 accepts either differential or single-ended input. The input must be AC coupled. Transformer coupling is not supported. The LMH0074 correctly handles equalizer pathological signals for standard definition serial digital video, as described in SMPTE RP 178. OUTPUT INTERFACING The SDO and SDO outputs are internally loaded with 50Ω. They produce a 750 mVP-P differential output, or a 375 mVP-P single-ended output. 5 www.national.com LMH0074 Application Information PCB LAYOUT RECOMMENDATIONS Please refer to the following Application Note on National's website: AN-1372, “LMH0034 PCB Layout Techniques.” The PCB layout techniques in the application note apply to the LMH0074 as well. SUPPLY CURRENT VS. CABLE LENGTH The supply current (ICC) depends on the amount of cable being equalized. The current is highest for short cable and decreases as the cable length is increased. Figure 1 shows supply current vs. Belden 1694A cable length for 270 Mbps data. 30027515 FIGURE 1. Supply Current vs. Belden 1694A Cable Length, 270 Mbps www.national.com 6 LMH0074 Physical Dimensions inches (millimeters) unless otherwise noted 16-Pin LLP Order Number LMH0074SQ NS Package Number SQB16A 7 www.national.com LMH0074 SMPTE 259M / 344M Adaptive Cable Equalizer Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers Audio Clock and Timing Data Converters Interface LVDS Power Management Switching Regulators LDOs LED Lighting Voltage Reference PowerWise® Solutions Temperature Sensors Wireless (PLL/VCO) www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/vref www.national.com/powerwise WEBENCH® Tools App Notes Reference Designs Samples Eval Boards Packaging Green Compliance Distributors Quality and Reliability Feedback/Support Design Made Easy Solutions Mil/Aero PowerWise® Design University Design Support www.national.com/webench www.national.com/appnotes www.national.com/refdesigns www.national.com/samples www.national.com/evalboards www.national.com/packaging www.national.com/quality/green www.national.com/contacts www.national.com/quality www.national.com/feedback www.national.com/easy www.national.com/solutions www.national.com/milaero www.national.com/solarmagic www.national.com/training Serial Digital Interface (SDI) www.national.com/sdi www.national.com/wireless www.national.com/tempsensors SolarMagic™ THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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