February 2006 LMH0024 3.3V SMPTE 259M / 344M Adaptive Cable Equalizer General Description Features The LMH0024 SMPTE 259M / 344M adaptive cable equalizer is a monolithic integrated circuit for equalizing 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. n n n n The LMH0024 implements DC restoration to correctly handle pathological data conditions. DC restoration can be bypassed for low data rate applications. The equalizer is flexible in allowing either single-ended or differential input drive. Additional features include a mute pin which can be used to manually mute the output and a cable length indicator which determines the amount of cable being equalized. n n n n n n n SMPTE 259M and SMPTE 344M compliant Supports DVB-ASI at 270 Mbps Data rates: 143 Mbps to 540 Mbps Equalizes up to 350 meters of Belden 1694A at 270 Mbps Manual bypass, cable length indicator, and output mute Single-ended or differential input 50Ω differential outputs Single 3.3V supply operation Industrial temperature range: −40˚C to +85˚C 198mW typical power consumption with 3.3V supply Footprint compatible with the LMH0034 and the GS9064 Applications n SMPTE 259M and SMPTE 344M serial digital interfaces n Serial digital data equalization and reception n Data recovery equalization Typical Application 20172501 © 2006 National Semiconductor Corporation DS201725 www.national.com LMH0024 SMPTE 259M / 344M Adaptive Cable Equalizer PRELIMINARY LMH0024 Absolute Maximum Ratings (Note 1) Supply Voltage Input Voltage (all inputs) Storage Temperature Range Recommended Operating Conditions −0.5V to 3.6V −0.3V to VCC+0.3V Supply Voltage (VCC – VEE) 3.3V ± 5% −65˚C to +150˚C Input Coupling Capacitance 1.0 µF Junction Temperature +150˚C Lead Temperature (Soldering 4 Sec) AEC Capacitor (Connected between AEC+ and AEC-) 1.0 µF +260˚C Operating Free Air Temperature (TA) −40˚C to +85˚C Package Thermal Resistance θJA 16-pin SOIC θJC 16-pin SOIC +115˚C/W +105˚C/W ESD Rating (HBM) 8kV ESD Rating (MM) 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 Conditions Reference At LMH0024 input, (Notes 4, 6) VCMOUT Output Common Mode Voltage VSDO Min SDI, SDI 50Ω load, differential CLI DC Voltage 0m cable MUTE Input Voltage Min to mute outputs 720 CLI no signal 800 Supply Current www.national.com V 950 (Note 7) 750 mVP-P 2.5 V V 3.0 V 60 2 mVP−P V 1.2 MUTE Units VCC – VSDO/2 Max to force outputs active ICC Max 1.9 SDO, SDO Output Voltage Swing Typ 2.0 V 77 mA Over Supply Voltage and Operating Temperature ranges, unless otherwise specified (Note 3). Symbol Parameter BRSDI Maximum Equalized Cable Length (with equalizer pathological) tr,tf Conditions Input Data Rate Reference Min SDI, SDI 143 Typ Max Units 540 Mbps 270 Mbps, Belden 1694A, 0.2UI output jitter, (Note 4) 350 m 270 Mbps, Belden 8281, 0.2UI output jitter, (Note 4) 280 m 540 Mbps, Belden 1694A, 0.2UI output jitter, (Note 4) 250 m 540 Mbps, Belden 8281, 0.2UI output jitter, (Note 4) 180 m Output Rise Time, Fall Time 20% – 80%, (Note 4) 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) RLIN Input Return Loss (Note 8) RIN Input Resistance single-ended CIN Input Capacitance single-ended, (Note 5) SDO, SDO SDI, SDI 15 50 Ω 18-20 dB 1.3 kΩ 1 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 LMH0024 meets this specification on the SD034 evaluation board from 5MHz to 1.5GHz. 3 www.national.com LMH0024 AC Electrical Characteristics LMH0024 Connection Diagram 20172503 16-Pin SOIC Order Number LMH0024MA See NS Package Number M16A Pin Descriptions Pin # 1 Name Description CLI Cable length indicator. Provides a voltage inversely proportional to the cable length being equalized. Positive power supply (+3.3V). 2 VCC 3 VEE Negative power supply (ground). 4 SDI Serial data true input. 5 SDI Serial data complement input. 6 VEE Negative power supply (ground). 7 AEC+ AEC loop filter external capacitor (1µF) positive connection. 8 AEC- AEC loop filter external capacitor (1µF) negative connection. 9 BYPASS Bypasses equalization and DC restoration when high. No equalization occurs in this mode. 10 NC No connect. 11 VEE Negative power supply (ground). 12 SDO Serial data complement output. 13 SDO Serial data true output. 14 VEE Negative power supply (ground). 15 VCC Positive power supply (+3.3V). 16 MUTE Output mute. To force SDO and SDO to mute, tie to VCC. To disable MUTE, tie to GND. Typical application is MUTE tied to GND to enable the outputs. MUTE must be tied either high or low; it may not be left unconnected. www.national.com 4 LMH0024 Block Diagram 20172502 INPUT INTERFACING The LMH0024 accepts either differential or single-ended input. The input must be AC coupled. Transformer coupling is not supported. The LMH0024 correctly handles equalizer pathological signals for standard definition serial digital video, as described in SMPTE RP 178. 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. Cable Length Indicator (CLI) is derived from this block. The Output Driver produces SDO and SDO. SDO and SDO may be force to mute by activating MUTE. 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. Application Information PCB LAYOUT RECOMMENDATIONS Please refer to the following Application Note for the CLC034 on National’s website: AN-1372, “CLC034 PCB Layout Techniques.” The PCB layout techniques in this application note apply to the LMH0024 as well. CABLE LENGTH INDICATOR (CLI) The cable length indicator provides a voltage to indicate the length of cable being equalized. The CLI voltage decreases as the cable length increases. REPLACING THE GENNUM GS9064 The LMH0024 is footprint compatible with the Gennum GS9064. Pin 16 (MUTE) of the LMH0024 must be connect to ground for correct operation. MUTE MUTE can be used to manually mute or enable the LMH0024 outputs. MUTE must be tied to a low-level input or ground for SDO and SDO to be active. Applying a high input to MUTE will mute the LMH0024 outputs. 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. 5 www.national.com LMH0024 Application Information (Continued) 20172515 FIGURE 1. Supply Current vs. Belden 1694A Cable Length, 270 Mbps www.national.com 6 LMH0024 SMPTE 259M / 344M Adaptive Cable Equalizer Physical Dimensions inches (millimeters) unless otherwise noted 16-Pin SOIC Order Number LMH0024MA NS Package Number M16A 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. 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