19-0724; Rev 0; 5/07 2.5Gbps PCI Express Passive Switches The MAX4888/MAX4889 high-speed passive switches route PCI Express® (PCIe) data between two possible destinations. The MAX4888 is a quad single-pole/doublethrow (4 x SPDT) switch ideally suited for switching two half lanes of PCIe data between two destinations. The MAX4889 is an octal single-pole/double-throw (8 x SPDT) switch ideal for switching four half lanes of PCIe data between four destinations. The MAX4888/MAX4889 feature a single digital control input (SEL) to switch signal paths. The MAX4888/MAX4889 are fully specified to operate from a single 3.0V to 3.6V power supply and also operate down to +1.65V. The MAX4888 is available in a 3.5mm x 5.5mm, 28-pin TQFN package. The MAX4889 is available in a 3.5mm x 9.0mm, 42-pin TQFN package. Both devices operate over the -40°C to +85°C temperature range. Features ♦ Single 1.65V to 3.6V Power-Supply Voltage ♦ Low Same-Pair Skew of 7ps ♦ Low 120µA (Max) Quiescent Current ♦ Supports PCIe Gen I Data Rates ♦ Flow-Through Pin Configuration for Ease of Layout ♦ Industry-Compatible Pinout ♦ Lead-Free Packaging Ordering Information/ Selector Guide Desktop Computers PINPACKAGE CONFIGURATION PKG CODE MAX4888ETI+ 28 TQFN-EP* Two Half Lanes T283555-1 MAX4889ETO+ 42 TQFN-EP* Four Half Lanes T423590M-1 PART Applications Servers/Storage Area Networks Laptops PCI Express is a registered trademark of PCI-Sig Corp. Note: All devices are specified over the -40°C to +85°C operating temperature range. +Denotes lead-free package. *EP = Exposed paddle. Typical Application Circuit appears at end of data sheet. Pin Configurations NO4- NO4+ NO3- NO3+ NC4- NC4+ NC3- NC3+ V+ NO2- NO2+ NO1- NO1+ NC2- 8 9 10 11 12 13 14 15 16 17 GND 7 COM4- 6 COM4+ 5 GND 4 V+ 3 COM3- 2 COM3+ 1 GND 10 SEL 9 V+ COM1+ 8 COM2- N.C. 7 GND SEL 6 N.C. GND 5 V+ 4 COM2- 3 COM2+ 2 COM1- 1 18 V+ + COM2+ 11 V+ + V+ V+ 28 19 GND *EP V+ 42 GND 12 GND *EP MAX4889 GND 41 COM1- GND 27 20 V+ V+ 40 GND 13 V+ MAX4888 21 GND GND 39 COM1+ 14 GND V+ 26 NC2+ 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 24 23 22 21 20 19 18 17 16 15 GND 25 NC1- NC1+ NO2- NO2+ NO1- NO1+ V+ GND NC2- NC2+ NC1- NC1+ TOP VIEW TQFN TQFN *CONNECT EXPOSED PADDLE TO GROUND. ________________________________________________________________ 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 MAX4888/MAX4889 General Description MAX4888/MAX4889 2.5Gbps PCI Express Passive Switches ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND, unless otherwise noted.) V+ .............................................................................-0.3V to +4V SEL, COM__, NO__, NC__ (Note 1) .............-0.3V to (V+ + 0.3V) | COM__ - NO__ |, | COM__ - NC__ | (Note 1) ...................0 to 2V Continuous Current (COM_ to NO__/NC__) .....................±70mA Peak Current (COM__ to NO__/NC__) (pulsed at 1ms, 10% duty cycle)..................................±70mA Continuous Current (SEL).................................................±30mA Peak Current (SEL) (pulsed at 1ms, 10% duty cycle)................................±150mA Continuous Power Dissipation (TA = +70°C) 28-Pin TQFN (derate 20.8mW/°C above +70°C) ....1666.7mW 42-Pin TQFN (derate 35.7mW/°C above +70°C) ....2857.1mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Junction Temperature ......................................................+150°C Note 1: Signals on SEL, NO__, NC__ or COM__ exceeding V+ or GND are clamped by internal diodes. Limit forward-diode current to maximum current rating. 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 (V+ = 3.0V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at V+ = 3.3V, TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS ANALOG SWITCH Analog-Signal Range Voltage Between COM and NO/NC On-Resistance VCOM_, VNO_, VNC_ -0.1 (V+ - 1.2) V | VCOM_ VNO_ | , | VCOM_ VNC_ | 0 1.8 V RON V+ = 3.0V, ICOM_ = 15mA, VNO_ or VNC_ = 0V, 1.8V Ω 7 On-Resistance Match Between Pairs of Same Channel ΔRON V+ = 3.0V, ICOM_ = 15mA, VNO_ or VNC_ = 0V (Notes 3, 4) 0.1 1 Ω On-Resistance Match Between Channels ΔRON V+ = 3.0V, ICOM_ = 15mA, VNO_ or VNC_ = 0V (Notes 3, 4) 0.6 2 Ω 0.06 2 Ω On-Resistance Flatness RFLAT(ON) V+ = 3.0V, ICOM_ = 15mA VNO_ or VNC_ = 0V, 1.8V (Notes 4, 5) NO_ or NC_ Off-Leakage Current INO_(OFF) INC_(OFF) V+ = 3.6V; VCOM_ = 0V, 1.8V; VNO_ or VNC_ = 1.8V, 0V -1 +1 µA COM_ On-Leakage Current ICOM_(ON) V+ = 3.6V; VCOM_ = 0V, 1.8V; VNO_ or VNC_ = VCOM_ or unconnected -1 +1 µA 2 _______________________________________________________________________________________ 2.5Gbps PCI Express Passive Switches (V+ = 3.0V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at V+ = 3.3V, TA = +25°C.) (Note 2) PARAMETER SYMBOL TYP MAX UNITS VNO_ or VNC_ = 1.0V, RL = 50Ω, Figure 1 90 250 ns tOFF VNO_ or VNC_ = 1.0V, RL = 50Ω, Figure 1 10 50 tPD RS = RL = 50Ω, unbalanced, Figure 2 50 ps Output Skew Between Pairs tSK1 RS = RL = 50Ω, unbalanced; skew between any two pairs, Figure 2 50 ps Output Skew Between Same Pair tSK2 RS = RL = 50Ω, unbalanced; skew between two lines on same pair, Figure 2 10 ps DYNAMIC Turn-On Time tON Turn-Off Time Propagation Delay On-Loss GLOS Crosstalk VCT1 Signaling Data Rate Off-Isolation NO_/NC_ Off-Capacitance COM_ On-Capacitance CONDITIONS RS = RL = 50Ω, unbalanced, Figure 3 Crosstalk between any two pairs, RS = RL = 50Ω, unbalanced, Figure 3 BR RS = RL = 50Ω VISO Signal = 0dBm, RS = RL = 50Ω, Figure 3 MIN 1MHz < f < 100MHz -0.5 500MHz < f < 1.25GHz -1.4 f = 50MHz -53 f = 1.25GHz -32 dB dB 3.0 f = 10MHz -56 f = 1.25GHz -26 Gbps dB CNO_/NC_(OFF) Figure 4 CCOM_(ON) ns Figure 4 1 pF 2 pF LOGIC INPUT Input-Logic Low VIL Input-Logic High VIH Input-Logic Hysteresis VHYST Input Leakage Current IIN 0.5 1.4 100 VSEL = 0V or V+ V V mV -1 +1 µA 1.65 3.60 V POWER SUPPLY Power-Supply Range V+ V+ Supply Current I+ VSEL = 0V or V+ MAX4888 60 MAX4889 120 µA Note 2: All units are 100% production tested at TA = +85°C. Limits over the operating temperature range are guaranteed by design and characterization and are not production tested. Note 3: ΔRON = RON (MAX) - RON (MIN). Note 4: Guaranteed by design. Not production tested. Note 5: Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the specified analog signal range. _______________________________________________________________________________________ 3 MAX4888/MAX4889 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) ON-RESISTANCE vs. VCOM (V+ = 1.8V) V+ = 1.8V 9.0 TA = +85°C 12 RON (Ω) 8.0 7.5 7.0 6.5 10 8 6 8 6 TA = -40°C 4 TA = +25°C 4 V+ = 3.3V 2 5.5 5.0 2 0 -0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 VCOM (V) 0 0.1 0.2 0.3 VCOM (V) 0.4 0.5 TA = +85°C RON (Ω) 10 8 6 4 2 -0.1 0.1 0.3 0.5 0.7 VCOM (V) 80 70 SUPPLY CURRENT (μA) TA = +25°C 0.6 SUPPLY CURRENT vs. TEMPERATURE (MAX4888) MAX4888/89 toc04 14 12 TA = -40°C 0 -0.1 ON-RESISTANCE vs. VCOM (V+ = 3.3V) TA = -40°C 0 60 V+ = 3.3V 50 40 V+ = 2.5V 30 20 10 V+ = 1.8V 0 -0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 VCOM (V) 4 TA = +85°C 12 MAX4888/89 toc05 6.0 TA = +25°C 10 V+ = 2.5V 14 RON (Ω) 8.5 14 MAX4888/89 toc02 9.5 MAX4888/89 toc01 10.0 ON-RESISTANCE vs. VCOM (V+ = 2.5V) MAX4888/89 toc03 ON-RESISTANCE vs. VCOM RON (Ω) MAX4888/MAX4889 2.5Gbps PCI Express Passive Switches -40 -15 10 35 TEMPERATURE (°C) 60 _______________________________________________________________________________________ 85 0.9 1.1 1.3 2.5Gbps PCI Express Passive Switches 0.8 VIL 0.7 140 120 100 80 60 40 20 0 0.6 0.5 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 SUPPLY VOLTAGE (V) NO_ tON 50mV/div NC_ tON NO_ tOFF NC_ tOFF VCOM_1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 SUPPLY VOLTAGE (V) MAX4888/89 toc09 EYE DIAGRAM (V+ = 2.5V, f = 1.25GHz, 600mVP-P PRBS SIGNAL, RS = RL = 50Ω)† VCOM_+ 50mV/div VCOM_+ 50ps/div *PRBS = PSEUDORANDOM BIT SEQUENCE †GEN I; 2.5Gps; UI = 400ps EYE DIAGRAM (V+ = 3.3V, f = 1.25GHz, 600mVP-P PRBS SIGNAL, RS = RL = 50Ω)† MAX4888/89 toc10 0.9 MAX4888/89 toc07 MAX4888/89 toc06 VIH tON/tOFF (ns) LOGIC THRESHOLD (V) 1.1 1.0 TURN-ON/-OFF TIME vs. SUPPLY VOLTAGE 240 220 200 180 160 MAX4888/89 toc08 LOGIC THRESHOLD vs. SUPPLY VOLTAGE 1.2 EYE DIAGRAM (V+ = 1.8V, f = 1.25GHz, 600mVP-P PRBS SIGNAL, RS = RL = 50Ω)† VCOM_+ 50mV/div VCOM_- VCOM_50ps/div *PRBS = PSEUDORANDOM BIT SEQUENCE †GEN I; 2.5Gps; UI = 400ps 50ps/div *PRBS = PSEUDORANDOM BIT SEQUENCE †GEN I; 2.5Gps; UI = 400ps _______________________________________________________________________________________ 5 MAX4888/MAX4889 Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) 2.5Gbps PCI Express Passive Switches MAX4888/MAX4889 Pin Description PIN 6 NAME FUNCTION MAX4888 MAX4889 1, 10, 12, 14, 20, 25, 27 1, 4, 10, 14, 17, 19, 21, 39, 41 GND 2 3, 9 4 5 6 7 9 — 2 3 6 7 SEL N.C. COM1+ COM1COM2+ COM2- 8, 11, 13, 19, 26, 28 5, 8, 13, 18, 20, 30, 40, 42 V+ 15 31 NO2- Analog Switch 2. Normally Open Negative Terminal. 16 32 NO2+ Analog Switch 2. Normally Open Positive Terminal. 17 33 NO1- Analog Switch 1. Normally Open Negative Terminal. 18 34 NO1+ Analog Switch 1. Normally Open Positive Terminal. Ground Digital Control Input No Connection. Not internally connected. Analog Switch 1. Common Positive Terminal. Analog Switch 1. Common Negative Terminal. Analog Switch 2. Common Positive Terminal. Analog Switch 2. Common Negative Terminal. Positive-Supply Voltage Input. Connect V+ to a 1.65V to 3.6V supply voltage. Bypass V+ to GND with a 0.1µF capacitor placed as close to the device as possible. (See the Board Layout section). 21 35 NC2- Analog Switch 2. Normally Closed Negative Terminal. 22 36 NC2+ Analog Switch 2. Normally Closed Positive Terminal. 23 37 NC1- Analog Switch 1. Normally Closed Negative Terminal. 24 38 NC1+ Analog Switch 1. Normally Closed Positive Terminal. — 11 COM3+ Analog Switch 3. Common Positive Terminal. — 12 COM3- Analog Switch 3. Common Negative Terminal. — 15 COM4+ Analog Switch 4. Common Positive Terminal. — 16 COM4- Analog Switch 4. Common Negative Terminal. — 22 NO4- — 23 NO4+ Analog Switch 4. Normally Open Positive Terminal. — 24 NO3- Analog Switch 3. Normally Open Negative Terminal. — 25 NO3+ Analog Switch 3. Normally Open Positive Terminal. — 26 NC4- Analog Switch 4. Normally Closed Negative Terminal. — 27 NC4+ Analog Switch 4. Normally Closed Positive Terminal. — 28 NC3- Analog Switch 3. Normally Closed Negative Terminal. — 29 NC3+ EP EP EP Analog Switch 4. Normally Open Negative Terminal. Analog Switch 3. Normally Closed Positive Terminal. Exposed Paddle. Connect EP to GND. _______________________________________________________________________________________ 2.5Gbps PCI Express Passive Switches MAX4888/MAX4889 3.3V VN_ LOGIC INPUT V+ COM_ NO_ OR NC_ 50% VIL VOUT RL t OFF CL SEL VOUT GND LOGIC INPUT t r < 5ns t f < 5ns VIH SWITCH OUTPUT 0.9 x V0UT 0.9 x VOUT 0V t ON CL INCLUDES FIXTURE AND STRAY CAPACITANCE. RL RL + RON VOUT = VN_ ( ) VN_ = VNO_ OR VNC_ Figure 1. Switching Time _______________________________________________________________________________________ 7 MAX4888/MAX4889 Test Circuits/Timing Diagrams 2.5Gbps PCI Express Passive Switches MAX4888/MAX4889 Test Circuits/Timing Diagrams (continued) 3.3V V+ RS IN+ MAX4888/MAX4889 NO_+ OR NC_+ COM_+ OUT+ RISE-TIME PROPAGATION DELAY = tPLHX OR tPLHY FALL-TIME PROPAGATION DELAY = tPHLX OR tPHLY RL RS IN- NO_- OR NC_- tSK1 = DIFFERENCE IN PROPAGATION DELAY (RISE-FALL) BETWEEN ANY TWO PAIRS COM_- tSK2 = | tPLHX - tPHLY | OR | tPHLX - tPLHY | BETWEEN TWO LINES ON THE SAME PAIR OUTRL SEL tINFALL tINRISE 1.5V 90% VIN+ 50% 90% 50% 10% 0V 10% 1.5V VIN- 50% 50% 0V tOUTRISE tPLHX tOUTFALL tPHLX 1.5V 90% VOUT+ 90% 50% 50% 10% 0V 10% 1.5V 50% VOUT- 50% 0V tPHLY tPLHY Figure 2. Propagation Delay and Output Skew 8 _______________________________________________________________________________________ 2.5Gbps PCI Express Passive Switches 3.3V 0.1μF V OFF-ISOLATION = 20log OUT VIN NETWORK ANALYZER 0V OR V+ V+ SEL NC_ 50Ω VIN COM_ 50Ω MAX4888/MAX4889 VOUT NO_ 50Ω MEAS REF 50Ω ON-LOSS = 20log VOUT VIN CROSSTALK = 20log VOUT VIN 50Ω GND MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS. OFF-ISOLATION IS MEASURED BETWEEN COM_ AND "OFF" NO_ OR NC_ TERMINAL ON EACH SWITCH. ON-LOSS IS MEASURED BETWEEN COM_ AND "ON" NO_ OR NC_ TERMINAL ON EACH SWITCH. CROSSTALK IS MEASURED BETWEEN ANY TWO PAIRS. SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED. Figure 3. On-Loss, Off-Isolation, and Crosstalk 0.1μF sets of eight lanes from a single 16-lane bus. The MAX4888/MAX4889 feature a single digital control input (SEL) to switch signal paths. The MAX4888/MAX4889 are fully specified to operate from a single 3.0V to 3.6V power supply and also operate down to 1.65V. 3.3V V+ COM_ MAX4888/MAX4889 Digital Control Input (SEL) SEL CAPACITANCE METER VIL OR VIH NC_ or NO_ GND The MAX4888/MAX4889 provide a single digital control input (SEL) to select the signal path between the COM__ and NO__/NC__ channels. The truth tables for the MAX4888/MAX4889 are depicted in the Functional Diagrams/Truth Table section. Drive SEL rail-to-rail to minimize power consumption. Analog Signal Levels Figure 4. Channel Off-/On-Capacitance Detailed Description The MAX4888/MAX4889 high-speed passive switches route PCIe data between two possible destinations. The MAX4888/MAX4889 are ideal for routing PCIe signals to change the system configuration. For example, in a graphics application, the MAX4888/MAX4889 create two The MAX4888/MAX4889 accept standard PCIe signals to a maximum of V+ - 1.2V. Signals on the COM_+ channels are routed to either the NO_+ or NC_+ channels, and signals on the COM_- channels are routed to either the NO_- or NC_- channels. The MAX4888/ MAX4889 are bidirectional switches, allowing COM__, NO__, and NC__ to be used as either inputs or outputs. _______________________________________________________________________________________ 9 MAX4888/MAX4889 Test Circuits/Timing Diagrams (continued) 2.5Gbps PCI Express Passive Switches MAX4888/MAX4889 Functional Diagrams/Truth Table V+ V+ MAX4888 MAX4889 COM1+ NC1+ COM1+ NC1+ COM1- NC1- COM1- NC1- NO1+ NO1+ NO1- NO1- COM2+ NC2+ COM2+ NC2+ COM2- NC2- COM2- NC2- SEL NO2+ NO2+ NO2- NO2COM3+ NC3+ COM3- NC3NO3+ GND NO3SEL COM__ TO COM__ TO NC__ NO__ 0 ON OFF 1 OFF ON COM4+ NC4+ COM4- NC4NO4+ NO4- SEL GND 10 ______________________________________________________________________________________ 2.5Gbps PCI Express Passive Switches DATA DIRECTION PCIe Switching The MAX4888/MAX4889 primary applications are aimed at reallocating PCIe lanes (see Figure 5). For example, in graphics applications, several manufacturers have found that it is possible to improve performance by a factor of nearly two by splitting a single 16-lane PCIe bus into two 8-lane buses. Two of the more prominent examples are SLI™ (Scaled Link Interface) and CrossFire™. The MAX4889 permits a computer motherboard to operate properly with a single 16-lane graphics card, and can later be updated to dual cards. The same motherboard can be used with dual cards where the user sets a jumper or a bit through software to switch between single- or dual-card operation. MAX4888/MAX4889 Applications Information ONE LANE MAX4888 MAX4889 DATA IS ROUTED TO EITHER BOARD A OR B NOTE: ONLY ONE LANE IS SHOWN FOR CLARITY Board Layout High-speed switches require proper layout and design procedures for optimum performance. Keep designcontrolled impedance PCB traces as short as possible or follow impedance layouts per the PCIe specification. Ensure that power-supply bypass capacitors are placed as close to the device as possible. Multiple bypass capacitors are recommended. Connect all grounds and the exposed pad to large ground planes. A B Figure 5. The MAX4888/MAX4889 Used as a Single-Lane Switch Chip Information PROCESS: CMOS CrossFire™ is a trademark of ATI Technologies, Inc. SLI™ is a trademark of NVIDIA Corporation. ______________________________________________________________________________________ 11 2.5Gbps PCI Express Passive Switches MAX4888/MAX4889 Typical Application Circuit PCIe GRAPHICS INTERFACE GRAPHICS CARD 1 PCIe BUS LANE 0 TX COM1+ NC1+ COM1- NC1NC2+ COM2+ LANE 1 TX COM2- MAX4889 LANE 3 TX NC2NC3+ COM3+ LANE 2 TX GRAPHICS CARD 2 COM3- NC3- COM4+ NC4+ NC4- COM4- NO1+ NO1NO2+ NO2NO3+ NO3NO4+ SEL NO4- CHANNEL SELECT COM1+ LANE 0 RX LANE 1 RX LANE 2 RX LANE 3 RX NC1+ COM1- NC1- COM2+ NC2+ COM2- MAX4889 NC2- COM3+ NC3+ COM3- NC3- COM4+ NC4+ COM4- NC4NO1+ NO1NO2+ NO2NO3+ NO3NO4+ SEL NO4- CHANNEL SELECT 12 ______________________________________________________________________________________ 2.5Gbps PCI Express Passive Switches ______________________________________________________________________________________ 28L THIN QFN.EPS ° 13 MAX4888/MAX4889 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) MAX4888/MAX4889 2.5Gbps PCI Express Passive Switches Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 14 ______________________________________________________________________________________ 2.5Gbps PCI Express Passive Switches ______________________________________________________________________________________ 42L THIN QFN.EPS ° 15 MAX4888/MAX4889 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) MAX4888/MAX4889 2.5Gbps PCI Express Passive Switches Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Products. Inc.