19-2289; Rev 0; 1/02 KIT ATION EVALU E L B A AVAIL 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver Features ♦ Single 3.3V Operation ♦ Four Independent Equalizers and Drivers ♦ 725mW at 3.3V Typical Power Dissipation ♦ Data Rates Up to 3.2Gbps ♦ Equalizer Automatically Adjusts for Different Cable Lengths ♦ 0 to 30dB Equalization at 1.6GHz (3.2Gbps) ♦ Loss-of-Signal (LOS) Indicator ♦ On-Chip Input and Output Terminations ♦ Low External Component Count ♦ 0°C to +85°C Operating Temperature Range Applications ♦ ESD Protection on Cable Inputs and Outputs High-Speed Links in Communications and Data Systems Ordering Information Backplane and Twin-Axial Cable Interconnects Category 5 UTP-Based Systems PART TEMP RANGE MAX3802UGK Digital Video Systems PIN-PACKAGE 0°C to +85°C 68 QFN* *Exposed pad Pin Configuration appears at end of data sheet. Typical Application Circuit 3.3V EP* 3.3V VCC EP* DIN_ 4 CARD 1 DOUT_ 4 COAX, TWIN-AX, OR PC BOARD x 4 4 4 CARD 2 MAX3802 EIN_ EOUT_ EOUT_ EIN_ MAX3802 4 VCC 4 COAX, TWIN-AX, OR PC BOARD x 4 4 DIN_ DOUT_ LOS_ RMOD_ CIM_ LOS_ RMOD_ 4 4 4 4 4 RMOD_ 4 CIM_ 4 RMOD_ THIS SYMBOL INDICATES A CONTROLLED-IMPEDANCE TRANSMISSION LINE. *EP MUST BE SOLDERED TO GROUND FOR PROPER THERMAL AND ELECTRICAL PERFORMANCE. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX3802 General Description The MAX3802 has four independent adaptive cable equalizers and cable drivers on a single chip. It is designed for coaxial and twin-axial cable point-to-point scrambled-data communication applications. The driver features differential current-mode logic (CML) inputs and outputs. The equalizer includes differential CML data inputs and outputs and a TTL loss-of-signal (LOS) output. The adaptive cable equalizer can equalize differential or single-ended signals at data rates up to 3.2Gbps. It automatically adjusts to attenuation caused by skineffect losses of 30dB at 1.6GHz. The equalizer effectively extends the usable length of copper cable in high-frequency interconnect applications. MAX3802 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC..............................................-0.5V to +6.0V Voltage at LOS_, CIM_, and RMOD_ .........-0.5V to (VCC + 0.5V) Voltage at EIN_+, EIN_-, DIN_+, and DIN_- ..........................(VCC - 1V) to (VCC + 0.5V) Current Out of EOUT_+, EOUT_-, DOUT_+, and DOUT_- ...................................................25mA Continuous Power Dissipation (TA = +85°C) 68-Pin QFN (derate 44.8mW/°C above +85°C) .............1.44W Operating Ambient Temperature Range ................0°C to +85°C Storage Ambient Temperature Range...............-55°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS (VCC = 3.14V to 3.46V, TA = 0°C to +85°C. Typical values are at VCC = 3.3V and TA = +25°C, unless otherwise noted.) PARAMETER Supply Current SYMBOL ICC CONDITIONS MIN Includes external load current (Note 1) TYP MAX UNITS 220 345 mA CABLE DRIVER INPUT SPECIFICATIONS Input Voltage (Single Ended) Input Voltage (Differential) VDIN_+, VDIN_- VCC 0.6 VCC + 0.2 V VDIN_ 400 1100 mVP-P Ω Input Impedance Single ended 40 50 60 RMOD_ = 10kΩ (Note 2) 750 825 1000 RMOD_ = 20kΩ (Note 2) 400 445 550 Single ended 50 62.5 75 Ω 400 mVP-P CABLE DRIVER OUTPUT SPECIFICATIONS Output Voltage (Differential) Output Impedance mVP-P CABLE EQUALIZER INPUT SPECIFICATIONS Minimum Cable Input (Differential) 3.2Gbps, 30dB cable loss (Note 3) Maximum Cable Input (Differential) 600 Input Impedance 40 50 mVP-P 60 Ω 1000 mVP-P 75 Ω CABLE EQUALIZER OUTPUT SPECIFICATIONS Output Voltage (Differential) (Note 2) 500 Output Impedance Single ended 50 Output high (Note 4) 2.4 Voltage at LOS_ 2 62.5 Output low (Note 4) _______________________________________________________________________________________ 0.4 V 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver (VCC = 3.14V to 3.46V, TA = 0°C to +85°C. Typical values are at VCC = 3.3V and TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS Maximum Input Data Rate MIN TYP MAX 3.2 UNITS Gbps CABLE DRIVER SPECIFICATIONS Random Jitter 3.2Gbps input 2.7 4 mUIRMS Deterministic Jitter (Notes 6, 9) 20 60 mUIP-P Output Edge Speed 20% to 80% 60 90 ps Input Return Loss (Differential) ≤ 2.5GHz -20 dB Output Return Loss (Differential) ≤ 2.5GHz -13 dB EQUALIZER SPECIFICATIONS Residual Jitter (Notes 7, 9) 0dB cable loss (Note 8) 0.10 0.24 24dB cable loss (Note 8) 0.11 0.20 30dB cable loss (Note 8) 0.08 0.20 90 UIP-P Output Edge Speed 20% to 80% 60 Input Return Loss (Differential) ≤ 2.5GHz -16 dB Output Return Loss (Differential) ≤ 2.5GHz -14 dB Equalizer Compensation 1.6GHz (skin-effect losses only) Equalizer Time Constant (Note 10) 30 ps dB 6 µs Equalizer total currents (equalizer with maximum equalization) and RMOD = 10kΩ (maximum driver swing). Input voltage within specification limits, 50Ω to VCC at each output. Minimum cable input for LOS_ to deassert high. 100kΩ load to ground. The minimum input signal level that turns off the LOS_ alarm depends on the data rate and cable length. AC electrical characteristics are guaranteed by design and characterization. VDIN_ = 400mVP-P to 1100mVP-P (differential), 10kΩ ≤ RMOD_ ≤ 20kΩ, 3.2Gbps 213 -1 PRBS plus 100 consecutive ones and 100 consecutive zeros. Note 7: Includes random jitter and deterministic jitter for BER of 10-12. Note 8: Differential cable input voltage = 400mVP-P, 3.2Gbps 213 -1 PRBS plus 100 consecutive ones and 100 consecutive zeros. Note 9: Isolation test: three channels driven with identical 3.2Gbps PRBS with maximum input signal to each equalizer and maximum input signal on driver. The measured channel meets the residual and random jitter specifications with an uncorrelated 3.2Gbps PRBS data at minimum input signal level on equalizer and maximum signal level on driver. Note 10: Equalizer time constant measured from data on to closed-loop operation. Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: _______________________________________________________________________________________ 3 MAX3802 AC ELECTRICAL CHARACTERISTICS Typical Operating Characteristics (VCC = 3.3V, TA = +25°C, all jitter measurements done at 3.2Gbps, 600mV cable input with 213 - 1 PRBS pattern with 100 consecutive ones and 100 consecutive zeros substituted. Note: Test pattern produces near-worst-case jitter results. Results vary with pattern, unless otherwise noted.) 210 180 1100 40 30 20 1000 900 800 30 50 70 -10 -20 600 -30 500 -40 -50 4 90 7 10 13 16 19 0 22 DRIVER OUTPUT RETURN LOSS (S22) 30 40 30 30 10 GAIN (dB) 10 GAIN (dB) 20 10 0 -10 0 -10 -20 -20 -20 -30 -30 -30 -40 -40 -40 -50 -50 0.8 1.6 2.4 3.2 4.0 4.0 40 20 -10 3.2 50 20 0 2.4 EQUALIZER OUTPUT RETURN LOSS (S22) EQUALIZER INPUT RETURN LOSS (S11) MAX3802 toc05 40 1.6 FREQUENCY (GHz) 50 MAX3802 toc04 50 0 0.8 RMOD (kΩ) TEMPERATURE (°C) -50 0 0.8 1.6 2.4 3.2 0 4.0 0.8 1.6 2.4 3.2 4.0 FREQUENCY (GHz) FREQUENCY (GHz) FREQUENCY (GHz) EQUALIZER RESIDUAL JITTER vs. POWER-SUPPLY NOISE (100mVP-P SINE WAVE) (40ft OF TENSOLITE TWIN-AX, 400mVP-P DIFFERENTIAL INPUT) EQUALIZER RESIDUAL JITTER vs. CABLE INPUT AMPLITUDE (RG179B 75Ω COAXIAL CABLE, SINGLE ENDED) EQUALIZER RESIDUAL JITTER vs. CABLE INPUT AMPLITUDE (TENSOLITE TWIN-AX–DIFFERENTIAL) 115 95 105 85 65 JITTER (psP-P) JITTER (psP-P) 25ft 75 95 72ft 85 75 55 1 NOISE FREQUENCY (MHz) 10 100 10ft 40ft 35 45 0.1 65 45 55 0.01 70ft 75 55 65 45 0.001 MAX3802 toc09 85 105 MAX3802 toc08 125 MAX3802 toc07 95 4 0 MAX3802 toc06 10 10 700 400 -10 MAX3802 toc03 MAX3802 toc02 1200 150 GAIN (dB) 50 GAIN (dB) 240 1300 DRIVER OUTPUT VOLTAGE (mV) 270 SUPPLY CURRENT (mA) MAX3802 toc01 RMOD = 15kΩ ALL CHANNELS AT MAX EQUALIZATION DRIVER INPUT RETURN LOSS (S11) CABLE DRIVER OUTPUT vs. RMOD SUPPLY CURRENT vs. TEMPERATURE 300 JITTER (psP-P) MAX3802 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver 150 300 450 600 750 900 CABLE INPUT AMPLITUDE (mVP-P) 300 450 600 750 900 1050 1200 CABLE DIFFERENTIAL INPUT AMPLITUDE (mVP-P) _______________________________________________________________________________________ 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver 45 70 3.2Gbps 60 35 25 50 50 60 70 40 25 35 45 55 40 65 50 60 70 80 90 CABLE LENGTH (ft) CABLE LENGTH (ft) LINE LENGTH (in) CIM VOLTAGE vs. CABLE LENGTH (TENSOLITE TWIN-AX, 400mVP-P DIFFERENTIAL) EQUALIZER INPUT AFTER 115ft OF CABLE (TOP) EQUALIZER OUTPUT (BOTTOM) EQUALIZER OUTPUT EYE DIAGRAM AFTER 155ft OF 50Ω GORE-89 CABLE (400mVP-P) MAX3802 toc15 0.25 MAX3802 toc14 MAX3802 toc13 0.30 0.20 0.15 0.10 0.05 0 10 20 30 40 50 60 70 48ps/div (3.2Gbps) CABLE LENGTH (ft) EQUALIZER OUTPUT EYE DIAGRAM AFTER 70ft OF TENSOLITE TWIN-AX CABLE (27 - 1 PRBS) 60ps/div (2.5Gbps) MAX3802 toc17 EQUALIZER OUTPUT EYE DIAGRAM AFTER 72ft OF 75Ω RG179 CABLE (300mVP-P SINGLE ENDED, 223 - 1 PRBS) 60ps/div (2.5Gbps) MAX3802 toc18 CABLE OUTPUT EYE DIAGRAM AFTER 70ft OF TENSOLITE TWIN-AX CABLE (27 - 1 PRBS NO EQUALIZATION) MAX3802 toc16 CIM VOLTAGE (VCC - VCIM) (V) 622Mbps 40 40 2.5Gbps 622Mbps 622Mbps 30 3.2Gbps 70 2.5Gbps 50 20 80 60 2.5Gbps 10 90 JITTER (psP-P) 3.2Gbps 55 80 JITTER (psP-P) 65 100 MAX3802 toc11 75 JITTER (psP-P) 90 MAX3802 toc10 85 EQUALIZER RESIDUAL JITTER vs. LINE LENGTH (FR-4 6mil STRIPLINE, 300mVP-P SINGLE ENDED) EQUALIZER RESIDUAL JITTER vs. CABLE LENGTH (RG179B 75Ω COAXIAL, 300mVP-P SINGLE ENDED) MAX3802 toc12 EQUALIZER RESIDUAL JITTER vs. CABLE LENGTH (TENSOLITE TWIN-AX, 400mVP-P DIFFERENTIAL INPUT) 48ps/div (3.2Gbps) _______________________________________________________________________________________ 5 MAX3802 Typical Operating Characteristics (continued) (VCC = 3.3V, TA = +25°C, all jitter measurements done at 3.2Gbps, 600mV cable input with 213 - 1 PRBS pattern with 100 consecutive ones and 100 consecutive zeros substituted. Note: Test pattern produces near-worst-case jitter results. Results vary with pattern, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = 3.3V, TA = +25°C, all jitter measurements done at 3.2Gbps, 600mV cable input with 213 - 1 PRBS pattern with 100 consecutive ones and 100 consecutive zeros substituted. Note: Test pattern produces near-worst-case jitter results. Results vary with pattern, unless otherwise noted.) EQUALIZER OUTPUT EYE DIAGRAM AFTER 288ft OF RG59 CABLE (300mVP-P SINGLE ENDED, 223 - 1 PRBS) 60ps/div (2.5Gbps) EQUALIZER OUTPUT EYE DIAGRAM AFTER 50ft OF MADISON 14887 SHIELDED TWISTED-PAIR CABLE (27 - 1 PRBS) 60ps/div (2.5Gbps) MAX3802 toc21 MAX3802 toc20 EQUALIZER OUTPUT EYE DIAGRAM AFTER 60in OF FR-4 6mil STRIPLINE (DIFFERENTIAL, 27 - 1 PRBS) MAX3802 toc19 MAX3802 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver 60ps/div (2.5Gbps) Pin Description 6 PIN NAME 1, 4, 6, 9 VCCE1 3.3V Supply Voltage for Equalizer 1 FUNCTION 2 EIN1- Negative Equalizer 1 Input, CML 3 EIN1+ Positive Equalizer 1 Input, CML 5 CIM1 Cable Integrity Monitor 1 Output 7 EOUT1- 8 EOUT1+ Negative Equalizer 1 Output, CML Positive Equalizer 1 Output, CML 10 RMOD1 Driver 1 Output Modulation Adjust 11, 14 VCCD1 3.3V Supply Voltage for Driver 1 12 DOUT1- Negative Driver 1 Output, CML 13 DOUT1+ Positive Driver 1 Output, CML 15 DIN1- Negative Driver 1 Input, CML 16 DIN1+ Positive Driver 1 Input, CML 17 LOS1 Equalizer 1 Loss-of-Signal, TTL, Active Low 18, 21, 23, 26 VCCE2 3.3V Supply Voltage for Equalizer 2 19 EIN2- Negative Equalizer 2 Input, CML 20 EIN2+ Positive Equalizer 2 Input, CML 22 CIM2 Cable Integrity Monitor 2 Output 24 EOUT2- Negative Equalizer 2 Output, CML 25 EOUT2+ Positive Equalizer 2 Output, CML 27 RMOD2 Driver 2 Output Modulation Adjust 28, 31 VCCD2 3.3V Supply Voltage for Driver 2 29 DOUT2- Negative Driver 2 Output, CML 30 DOUT2+ Positive Driver 2 Output, CML _______________________________________________________________________________________ 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver PIN NAME FUNCTION 32 DIN2- 33 DIN2+ Negative Driver 2 Input, CML Positive Driver 2 Input, CML 34 LOS2 Equalizer 2 Loss-of-Signal, TTL, Active Low 35, 38, 40, 43 VCCE3 3.3V Supply Voltage for Equalizer 3 36 EIN3- Negative Equalizer 3 Input, CML 37 EIN3+ Positive Equalizer 3 Input, CML 39 CIM3 Cable Integrity Monitor 3 Output 41 EOUT3- Negative Equalizer 3 Output, CML 42 EOUT3+ Positive Equalizer 3 Output, CML 44 RMOD3 Driver 3 Output Modulation Adjust 45, 48 VCCD3 3.3V Supply Voltage for Driver 3 46 DOUT3- Negative Driver 3 Output, CML 47 DOUT3+ Positive Driver 3 Output, CML 49 DIN3- Negative Driver 3 Input, CML 50 DIN3+ Positive Driver 3 Input, CML 51 LOS3 Equalizer 3 Loss-of-Signal, TTL, Active Low 52, 55, 57, 60 VCCE4 3.3V Supply Voltage for Equalizer 4 53 EIN4- Negative Equalizer 4 Input, CML 54 EIN4+ Positive Equalizer 4 Input, CML 56 CIM4 Cable Integrity Monitor 4 Output 58 EOUT4- Negative Equalizer 4 Output, CML 59 EOUT4+ Positive Equalizer 4 Output, CML 61 RMOD4 Driver 4 Output Modulation Adjust 62, 65 VCCD4 3.3V Supply Voltage for Driver 4 63 DOUT4- Negative Driver 4 Output, CML 64 DOUT4+ Positive Driver 4 Output, CML 66 DIN4- Negative Driver 4 Input, CML 67 DIN4+ Positive Driver 4 Input, CML 68 LOS4 Equalizer 4 Loss-of-Signal, TTL, Active Low EP Exposed Pad Ground. Must be soldered to the circuit board ground for proper thermal and electrical performance (see EP Package). _______________________________________________________________________________________ 7 MAX3802 Pin Description (continued) to 3.2Gbps. It automatically adjusts to attenuation levels of 30dB at 1.6GHz (due to skin-effect losses in copper cable). The equalizer consists of a CML input buffer, a flat-response amplifier, a skin-effect compensation amplifier, a current-steering network, a dual power-detector feedback loop, an output limiting amplifier, and a CML output buffer (Figure 1). Detailed Description The MAX3802 has four independent adaptive equalizers (receivers) and four independent drivers. Disconnecting the power pins of unused equalizers and drivers lowers the power consumption of the MAX3802. Equalizer and driver descriptions apply to the four identical sections. General Theory of Operation The shape of the power spectrum of a random bit stream can be described by the square of the wellknown sinc function, where sinc(f) = sin(πf)/(πf) for f ≠ 0. For sufficiently long bit patterns (nonrandom bit stream), sinc2(f) is a good approximation. From the shape of the sinc2(f) function, the ratio of the power densities at any two frequencies can be estimated. The MAX3802 adaptive equalizer employs this principle by incorporating a feedback loop that continuously monitors the power at high- and low-frequency bands and Cable Driver The cable driver accepts differential or single-ended CML input data at rates up to 3.2Gbps. The maximum CML output of the driver can be adjusted over a typical range of 445mV to 825mV by changing the value of the RMOD_ resistor between 10kΩ and 20kΩ (resistor connected between RMOD_ pin and ground). Adaptive Cable Equalizer The adaptive cable equalizer is capable of equalizing differential or single-ended CML input data at rates up LOOP FILTER |H(f)| FLAT RESPONSE AMP EIN_ POWER DETECTOR LOS_ DOUT_ VARIABLE ATTENUATOR Σ CML 2 SKINEFFECT COMP AMP |H(f)| 600MHz PWR DETECTOR MAX3802 200MHz PWR DETECTOR MAX3802 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver LIMITING AMP CML EOUT_ VARIABLE ATTENUATOR CURRENT-STEERING NETWORK √f 2 CML CABLE DRIVER CML RMOD_ RMOD_ Figure 1. MAX3802 Functional Diagram 8 2 _______________________________________________________________________________________ 2 DIN_ 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver CML Input and Output Buffers The input and output buffers are implemented using CML. Equivalent circuits are shown in Figures 2 and 3. For details on interfacing with CML, refer to Maxim Application Note HFAN-01.0, Interfacing Between CML, PECL, and LVDS. VCC MAX3802 50Ω 50Ω _IN_+ _IN_- ESD STRUCTURES Figure 2. CML Input Structure VCC MAX3802 62.5Ω ESD STRUCTURES 62.5Ω _OUT_+ _OUT_- Flat-Response and Skin-Effect Compensation Amplifiers The buffered input waveform is fed equally to two amplifiers—the flat-response amplifier and the skineffect compensation amplifier. The flat-response amplifier has a constant gain over the entire frequency range of the device, and the skin-effect compensation amplifier has a gain characteristic that approximates the inverse of the skin-effect attenuation in copper cable. The skin-effect attenuation, in dB per unit length, is proportional to the square root of the frequency. The output currents from the amplifiers are supplied to the current-steering network. Current-Steering Network The function of the current-steering network is to combine adjustable quantities of the output currents from the flat-response and skin-effect compensation amplifiers in order to achieve a desired current ratio. The ratio adjustment is controlled by the dual power-detector feedback loop. The current-steering network is implemented with a pair of variable attenuators that feed into a current-summing node. The variable attenuators are used to attenuate the output currents of the flat-response and skin-effect compensation amplifiers under control of the dual power-detector feedback loop. The outputs of the two attenuators are combined at the summing node and then fed to the output-limiting amplifier and the feedback loop. Dual Power-Detector Feedback Loop The outputs of the current-steering network are applied to the inputs of 200MHz and 600MHz power detectors. The outputs of the power detectors are applied to the loop-filter amplifier. This amplifier controls the variable attenuators in the current-steering network. Output Limiting Amplifier The output limiting amplifier amplifies the signal from the current-steering network to achieve the specified output voltage swing. Applications Information Refer to Maxim Application Note HFDN-10.0, Equalizing Gigabit Copper Cable Links with the MAX3800 (available at www.maxim-ic.com) for additional application information. Figure 3. CML Output Structure Selecting RMOD The cable driver output amplitude can be adjusted by connecting a resistor (RMOD) with a value from 10kΩ to 20kΩ between the RMOD_ pin and ground. The exact output amplitude of the driver is dependent on several _______________________________________________________________________________________ 9 MAX3802 dynamically adjusts the equalizer to maintain the correct power ratio. Data Spectrum for Equalizer Layout Considerations The MAX3802’s performance can be significantly affected by circuit board layout and design. Use good high-frequency design techniques, including minimizing ground inductance and using controlled-impedance transmission lines for the high-frequency data signals. Power-supply decoupling capacitors should be placed as close as possible to VCC. 10 63 62 61 60 59 58 EIN4- VCCE4 EIN4+ VCCE4 CIM4 VCCE4 EOUT4- VCCE4 EOUT4+ RMOD4 VCCD4 DOUT4- DOUT4+ DIN4- 67 66 65 64 57 56 55 54 53 52 VCCE1 1 51 LOS3 EIN1- 2 50 DIN3+ EIN1+ 3 49 DIN3- VCCE1 4 48 VCCD3 CIM1 5 47 DOUT3+ VCCE1 6 46 DOUT3- EOUT1- 7 45 VCCD3 EOUT1+ 8 VCCE1 9 44 RMOD3 MAX3802 43 VCCE3 RMOD1 10 42 EOUT3+ VCCD1 11 41 EOUT3- DOUT1- 12 40 VCCE3 DOUT1+ 13 39 CIM3 VCCD1 14 38 VCCE3 DIN1- 15 37 EIN3+ DIN1+ 16 36 EIN3- LOS1 17 35 VCCE3 QFN* *THE EXPOSED PAD OF THE QFN PACKAGE MUST BE SOLDERED TO GROUND FOR PROPER THERMAL AND ELECTRICAL OPERATION OF THE MAX3802. ______________________________________________________________________________________ LOS2 DIN2+ DIN2- VCCD2 DOUT2+ VCCD2 DOUT2- RMOD2 VCCE2 EOUT2+ EOUT2- VCCE2 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 CIM2 Single-Ended Operation For single-ended operation of the cable driver or equalizer, connect the unused input to ground through a series combination of a capacitor (of equal value to other AC-coupling capacitors) and a 50Ω resistor. Note that the MAX3802 is specified for differential operation. 68 VCCE2 The MAX3802 equalizer design requires the data stream be scrambled or coded to provide a rich frequency spectrum for the adaptation algorithm. Scrambled patterns or coded patterns with scrambled content, such as 64b/66b or SONET PRBS, are ideal. Some coded patterns, such as 8b/10b, lack low-frequency energy and can be nonoptimal, requiring the user to characterize the specific application. In the absence of an input signal (nonstandard application), amplified noise may appear at the output due to the large gain of the device. DIN4+ TOP VIEW VCCD4 Pin Configuration EIN2+ Loss-of-Signal (LOS_) Output Loss of signal is indicated by the LOS_ output. A low level on LOS_ indicates that the equalizer input power has dropped below a threshold. When there is sufficient input voltage to the channel (typically greater than 250mV), LOS_ is high. The LOS_ output is suitable for indicating problems with the transmission link caused by, for example, a broken cable or a defective driver. Chip Information TRANSISTOR COUNT: 5408 PROCESS: Bipolar (silicon germanium) LOS4 Cable Integrity Monitor The CIM_ output voltage is directly proportional to the output current of the loop amplifier (which controls the current-steering network; see Detailed Description). This is an analog voltage output that indicates the amount of equalization being applied. The amount of equalization (and thus the CIM_ output level) is affected by cable type, cable length, signal bandwidth, etc. See the Typical Operating Characteristics CIM Voltage vs. Cable Length for typical values under specific conditions. Exposed-Pad Package The EP on the 68-pin QFN provides a very low thermal resistance path for heat removal from the IC. The pad is the electrical ground on the MAX3802 and must be soldered to the circuit board ground for proper thermal and electrical performance. Refer to Maxim Application Note HFAN-08.1, Thermal Considerations for QFN and Other Exposed-Pad Packages (available at www.maximic.com) for additional application information. EIN2- factors. See the Typical Operating Characteristics Cable Driver Output Voltage vs. RMOD for typical values. VCCE2 MAX3802 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver 68L QFN, 10x10x09,EPS ______________________________________________________________________________________ 11 MAX3802 Package Information 3.2Gbps Quad Adaptive Cable Equalizer with Cable Driver MAX3802 Package Information (continued) Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.