LMH0074 SMPTE 259M / 344M Adaptive Cable Equalizer General Description Features 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 143 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. ■ ■ ■ ■ ■ SMPTE 259M and SMPTE 344M compliant Supports DVB-ASI at 270 Mbps High data rates: 143 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 © 2007 National Semiconductor Corporation 300275 www.national.com LMH0074 SMPTE 259M / 344M Adaptive Cable Equalizer December 5, 2007 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) Recommended Operating Conditions −0.5V to 3.6V −0.3V to VCC+0.3V −65°C to +150°C +150°C Supply Voltage (VCC – VEE) Input Coupling Capacitance AEC Capacitor (Connected between AEC+ and AEC-) Operating Free Air Temperature (TA) +260°C 3.3V ±5% 1.0 µF 1.0 µF −40°C to +85°C +43°C/W +9°C/W 8kV 250V DC Electrical Characteristics Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Notes 2, 3). Symbol Parameter VCMIN Input Common Mode Voltage VSDI Input Voltage Swing VCMOUT Output Common Mode Voltage VSDO Output Voltage Swing Conditions Reference Min SDI, SDI At LMH0074 input, (Notes 4, 6) 720 50Ω load, differential MUTEREF MUTEREF Range CD Output Voltage Carrier not present CD 2.6 MUTE 3.0 800 Supply Current www.national.com 950 (Note 7) 750 mVP-P 1.3 V 0.7 V V V V 63 2 mVP−P V Max to force outputs active ICC V 0.4 Min to mute outputs Units VCC – VSDO/2 Carrier present MUTE Input Voltage Max 1.9 SDO, SDO MUTEREF DC Voltage (floating) Typ 0.8 V 77 mA LMH0074 AC Electrical Characteristics Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3). Symbol Parameter BRSDI Jitter for various Cable Lengths (with equalizer pathological) tr,tf Conditions Input Data Rate Reference Min SDI, SDI 143 Typ Max Units 540 Mbps 270 Mbps, Belden 1694A, 400 meters (Note 4) 0.2 UI 270 Mbps, Belden 8281, 280 meters (Note 4) 0.2 UI Output Rise Time, Fall Time 20% – 80%, (Note 4) SDO, SDO 100 220 ps Mismatch in Rise/Fall Time (Note 4) 2 15 ps tOS Output Overshoot (Note 4) 1 5 % ROUT Output Resistance single-ended, (Note 5) 50 Ω RLIN Input Return Loss (Note 8) 18-20 dB RIN Input Resistance single-ended 1.3 kΩ CIN Input Capacitance single-ended, (Note 5) 1 pF SDI, SDI 15 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 # Name Description 1 VEE Negative power supply (ground). 2 SDI Serial data true input. 3 SDI Serial data complement input. 4 VEE Negative power supply (ground). 5 AEC+ AEC loop filter external capacitor (1µF) positive connection. 6 AEC- AEC loop filter external capacitor (1µF) negative connection. 7 BYPASS Bypasses equalization and DC restoration when high. No equalization occurs in this mode. 8 MUTEREF 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. 9 VEE Negative power supply (ground). 10 SDO Serial data complement output. 11 SDO Serial data true output. 12 VEE Negative power supply (ground). 13 VCC Positive power supply (+3.3V). 14 MUTE 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. 15 CD Carrier detect. CD is high when no signal is present. CD has no function in BYPASS mode. 16 VCC Positive power supply (+3.3V). www.national.com 4 LMH0074 Block Diagram 30027502 de-asserted and the outputs are muted is decreased. MUTEREF may be left unconnected for maximum equalization before muting. 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. 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. 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 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 Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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