19-2565; Rev 4; 10/07 5Gbps PCB Equalizer Features The MAX3784/MAX3784A 5Gbps equalizers provide compensation for transmission-medium losses in up to 40in of FR-4. They are optimized for short-run length and balanced codes such as 8b10b, as found in multiplexed 1.25Gbps Ethernet systems and 4.25Gbps Fibre Channel. The equalizers use differential CML data inputs and outputs. A standby mode reduces power consumption when the parts are not in use. The MAX3784/ MAX3784A are available in a 4mm × 4mm, 16-pin QFN package that consumes only 185mW at +3.3V. ♦ Spans 40in (1m) of FR-4 PCB ♦ 0.18UI Deterministic Jitter Up to 40in ♦ Low Power Consumption: 185mW (MAX3784) ♦ Equalization Reduces Intersymbol Interference ♦ Single +3.3V Supply ♦ Standby Mode ♦ Small 4mm × 4mm, 16-Pin QFN Package OUT+ OUT- GND TOP VIEW VCC Pin Configurations 12 11 10 9 Chassis Life Extension 4.25Gbps Fibre Channel 4x Multiplexed 1.25Gbps Ethernet (5Gbps) EN 13 8 N.C. N.C. 14 7 VCC 6 GND 5 N.C. MAX3784/ MAX3784A N.C. 15 TEMP RANGE PART G1644-1 1 2 3 4 MAX3784UTE+ 0°C to +85°C 16 TQFN-EP* T1644-3 GND 0°C to +85°C 16 QFN-EP* PKG CODE IN- MAX3784UGE PINPACKAGE IN+ *EP Ordering Information VCC N.C. 16 Applications MAX3784AUGE 0°C to +85°C 16 QFN-EP* G1644-1 MAX3784AUTE+ 0°C to +85°C 16 TQFN-EP* T1644-3 QFN * THE EXPOSED PAD MUST BE SOLDERED TO SUPPLY GROUND FOR CORRECT THERMAL AND ELECTRICAL PERFORMANCE. +Denotes a lead-free package. *Exposed pad. Pin Configurations continued at end of data sheet. Typical Application Circuit 1.25Gbps Rx Tx SWITCH CARD PCB BACKPLANE LINE CARD T/R 1 +3.3V SWITCH 1.25Gbps Rx Tx T/R 2 T/R 1 Tx IN +3.3V T/R 2 1.25Gbps Rx Tx T/R 3 Rx T/R 4 1.25Gbps Rx Tx 5Gbps T/R 3 OUT MAX3784/ MAX3784A IN MAX3784/ MAX3784A OUT Rx EQUALIZER Tx EQUALIZER T/R 4 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX3784/MAX3784A General Description MAX3784/MAX3784A 5Gbps PCB Equalizer ABSOLUTE MAXIMUM RATINGS Operating Ambient Temperature Range ................0°C to +85°C Storage Temperature Range .............................-55°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Supply Voltage, VCC.................................................-0.5V to +6V Input Voltage............................................(-0.5V) to (VCC + 0.5V) Continuous Output Current ...............................-25mA to +25mA Continuous Power Dissipation (TA = +85°C) 16-Pin QFN (derate 25mW/°C above +85°C) ............1600mW 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. ELECTRICAL CHARACTERISTICS (VCC = +3V to +3.6V, TA = 0°C to +85°C. Typical values are at VCC = +3.3V and TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX 185 250 EN = low Supply Power 30 EN = high Supply-Noise Tolerance (Note 1) Latency From input to output 10Hz < f < 100Hz 100 100Hz < f < 1MHz 40 1MHz < f < 2.5GHz UNITS mW mVP-P 10 200 ps CML RECEIVER INPUT Input Voltage Swing VIN Measured differentially at point A in Figure 1 Return Loss 100MHz to 2.5GHz Input Resistance Differential 400 1000 15 80 mVP-P dB 100 120 20in 0.13 0.21 40in 0.18 0.23 20in 0.08 0.14 40in 0.13 0.28 20in 0.04 0.07 40in 0.07 0.15 1.3 1.9 Ω EQUALIZATION Residual Deterministic Jitter, 5Gbps Table 1 (Notes 2–5) Residual Deterministic Jitter, 2.5Gbps Table 1 (Notes 2–5) Residual Deterministic Jitter, 1.25Gbps Table 1 (Notes 2–5) Random Jitter (Notes 5, 6) UIP-P UIP-P UIP-P psRMS CML TRANSMITTER OUTPUT (into 100Ω ±1Ω) MAX3784 400 600 MAX3784A 550 750 Output Voltage Swing VO Differential swing, measured differentially at point C in Figure 1 Transition Time tf, tr 20% to 80% (Notes 5, 8) 30 45 60 ps Single ended 40 50 60 Ω Output Resistance 2 _______________________________________________________________________________________ mVP-P 5Gbps PCB Equalizer (VCC = +3V to +3.6V, TA = 0°C to +85°C. Typical values are at VCC = +3.3V and TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS ENABLE CONTROL PIN Input High Voltage 1.5 V Input Low Voltage 0.5 V Input High Current (Note 7) -150 +10 µA Input Low Current (Note 7) -150 +10 µA Note 1: Allowed supply noise during jitter tests. Note 2: Test pattern. This is a combination of K28.5± characters running at the full bit rate and at one-quarter the bit rate. This simulates the multiplexing of four each 1.25Gbps Ethernet data streams. Pattern (hex) 100 bits 00 FFFF F0F0 FF 0000 0F0F (quarter rate K28.5+, quarter rate K28.5-) 3EB05 (K28.5± 00 1111 1010 11 0000 0101) Note 3: Difference in deterministic jitter between reference points A and C in Figure 1. Note 4: Signal source amplitude range is 400mVP-P to 1000mVP-P differential. Signal is applied differentially at point A as shown in Figure 1. The deterministic jitter at point B must be from media-induced loss and not from clock-source modulation. Deterministic jitter is measured at the 50% vertical level of the signal at point C. Note 5: Guaranteed by design and characterization. Note 6: Test pattern is K28.5 with 40in trace. Note 7: On-chip pullup resistor of 40kΩ (typ). Negative current indicates equalizer sources current. Note 8: Using 00 0001 1111 or equivalent pattern. Measured over entire input voltage range, max and min media loss and within 2in of output pins. SIGNAL SOURCE MAX3784/MAX3784A EQUALIZER BACKPLANE PCB A SMA CONNECTOR SMA CONNECTOR B C IN OUT 6mil LINE L ≤ 40in Figure 1. Test Conditions Table 1. PCB Assumptions (PCB material is FR-4) PARAMETER CONDITIONS MIN Transmission Line Edge-coupled stripline Relative Permittivity FR-4 or similar 4.4 Loss Tangent FR-4 or similar 0.02 Metal Thickness 0.7 mils (0.5oz copper) Impedance Differential TYP MAX 6 mils 4.5 0.022 0.7 90 100 UNITS — — mils 110 _______________________________________________________________________________________ 3 MAX3784/MAX3784A ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = +3.3V, measurements done at 5Gbps, 800mVP-P board input with 100-bit pattern from Note 2 of the EC Table, TA = +25°C, unless otherwise noted.) EQUALIZER INPUT EYE DIAGRAM BEFORE EQUALIZATION AT 5Gbps (40in, FR-4, 6-mil STRIPLINE) 80mV/ div 32ps/div 35ps/div 35ps/div DIFFERENTIAL RETURN LOSS DETERMINISTIC JITTER vs. LINE LENGTH DETERMINISTIC JITTER vs. AMPLITUDE (20in FR-4 STRIPLINE) 10 5 0 1.25GHz 70 60 2.5GHz 50 40 5GHz 30 90 1 2 3 4 70 60 50 40 10 10 5 2.5GHz 30 20 10 20 30 40 50 200 60 DETERMINISTIC JITTER vs. AMPLITUDE (40in FR-4 STRIPLINE) LATENCY vs. TEMPERATURE 80 400 50 1.25GHz 40 LATENCY (ps) 70 2.5GHz 300 200 5GHz 30 100 20 0 200 400 600 800 1000 INPUT AMPLITUDE (mVP-P) (FIGURE 1, POINT A) 1200 1000 1200 70 ICC MAX3784A 60 ICC MAX3784 50 40 30 20 10 10 0 800 SUPPLY CURRENT vs. TEMPERATURE SUPPLY CURRENT (mA) 90 600 80 MAX3784/4A toc08 MAX3784/4A toc07 500 400 INPUT AMPLITUDE (mVP-P) (FIGURE 1, POINT A) LINE LENGTH (in) (FR-4 6-mil STRIPLINE) 100 5GHz 1.25GHz 0 0 FREQUENCY (GHz) 60 80 20 0 0 MAX3784/4A toc06 MAX3784/4A toc05 80 100 MAX3784/4A toc09 15 90 DETERMINISTIC JITTER (ps) 20 100 DETERMINISTIC JITTER (ps) MAX3784/4A toc04 25 RETURN LOSS (dB) MAX3784/4A toc03 MAX3784/4A toc02 MAX3784/4A toc01 80mV/ div 30 4 EQUALIZER OUTPUT EYE DIAGRAM AFTER EQUALIZATION AT 5Gbps (40in, FR-4, 6-mil STRIPLINE, MAX3784A) EQUALIZER OUTPUT EYE DIAGRAM AFTER EQUALIZATION AT 5Gbps (40in, FR-4, 6-mil STRIPLINE, MAX3784) 55mV/ div DETERMINISTIC JITTER (ps) MAX3784/MAX3784A 5Gbps PCB Equalizer ISHUTDOWN 0 0 25 50 TEMPERATURE (°C) 75 100 0 25 50 TEMPERATURE (°C) _______________________________________________________________________________________ 75 5Gbps PCB Equalizer PIN NAME FUNCTION 1, 7, 12 VCC 2 IN+ Positive Input, CML 3 IN- Negative Input, CML 4, 6, 9 GND Supply Ground 5, 8, 14, 15, 16 N.C. No Connection. Leave unconnected. 10 OUT- Negative Output, CML 11 OUT+ Positive Output, CML 13 EN EP Exposed Pad +3.3V Supply Voltage Enable Equalizer. A logic high or open selects normal operation. A logic low selects low-power standby mode. Connect to Ground. The exposed pad must be soldered to the circuit board ground plane for proper thermal and electrical performance. 5Gbps EQUALIZER VCC OFFSET CANCELLATION LOWPASS FILTER IN+ 100Ω MAX3784/ MAX3784A 50Ω 50Ω OUT+ EQUALIZER LIMITER OUT- INVCC 40kΩ EN Figure 2. Functional Diagram Detailed Description General Theory of Operation The MAX3784/MAX3784A adaptive equalizers extend the reach of transmission lines in high-frequency backplane interconnect applications. They can be used for 4.25Gbps Fibre Channel, 4x 1.25Gbps Ethernet (5Gbps) and other NRZ, 8b10b or short (≤ 20 bits) CID data types. Internally, the MAX3784/MAX3784A are comprised of an equalizer control loop and limiting output driver. The equalizer block reduces intersymbol interference (ISI), compensating for frequency-dependent media-induced loss. The equalization control detects the spectral contents of the input signal and provides a control voltage to the equalizer core, adapting it to different media. The equalizer operation is optimized for short-run, DC-balanced transmission codes. Standby Mode Standby saves power when the equalizer is not in use. The EN logic input must be set high or open for normal operation. Logic low at EN forces the equalizer into the standby state. CML Input and Output Buffers The input and output buffers are implemented using current-mode logic (CML). Equivalent circuits are shown in Figures 3 and 4. For details on interfacing with CML, refer to Maxim Application Note HFAN-01.0: Introduction to LVDS, PECL, and CML. The common-mode voltage of the input and output is above +2.5V. AC-coupling capacitors are required when interfacing this part with devices terminated in voltages such as +1.8V. Values of 0.10µF or greater are recommended. _______________________________________________________________________________________________________ 5 MAX3784/MAX3784A Pin Description VCC VCC 50Ω 50Ω OUT+ OUT- 50Ω 50Ω 250μA Figure 3. CML Input Equivalent Circuit Figure 4. CML Output Equivalent Circuit Applications Information Alternate Data Rates The MAX3784/MAX3784A is optimized for automatic operation at 5Gbps. Equalization at other data rates, such as 1.25Gbps and 2.5Gbps, is possible. See the Typical Operating Characteristics for Deterministic Jitter vs. Line Length and Deterministic Jitter vs. Amplitude for typical performance at these data rates. Layout Considerations Circuit board layout and design can significantly affect the MAX3784/MAX3784As’ performance. Use good high-frequency design techniques, including minimizing ground inductance and connections and using controlled-impedance transmission lines for the high-frequency data signals. Route signals differentially to reduce EMI susceptibility and crosstalk. Solder the exposed pad to supply ground for proper thermal and electrical operation. Place power-supply decoupling capacitors as close as possible to the VCC pins. OUT+ OUT- GND TOP VIEW VCC Pin Configurations (continued) 12 11 10 9 EN 13 8 N.C. N.C. 14 7 VCC 6 GND 5 N.C. MAX3784 MAX3784A N.C. 15 *EP 1 2 3 4 IN- GND + IN+ N.C. 16 VCC MAX3784/MAX3784A 5Gbps PCB Equalizer TQFN * THE EXPOSED PAD MUST BE SOLDERED TO SUPPLY GROUND FOR CORRECT THERMAL AND ELECTRICAL PERFORMANCE. 6 _______________________________________________________________________________________ 5Gbps PCB Equalizer PACKAGE TYPE DOCUMENT NO. 16 QFN 21-0106 16 TQFN 21-0139 Revision History Pages changed at Rev 4: 1–7 (removed package drawings, replaced with table) 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7 © 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products. MAX3784/MAX3784A Package Information For the latest package outline information, go to www.maxim-ic.com/packages.