19-5573; Rev 1; 4/11 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) Features The MAX14978 high-performance, passive analog switch is ideal for switching Hi-Speed USB and SuperSpeed USB data between one source and two loads, or vice versa. The device can be used in desktop and notebook applications where SuperSpeed USB ports are in limited supply. The device consists of two sets of analog switches with one set used for USB low-speed, full-speed, and Hi-Speed signals and the second set used for USB SuperSpeed. The device operates from a single +3.3V supply. S Designed for SuperSpeed USB Applications: Low/Full/Hi-Speed (1.5/12/480Mbps) SuperSpeed (5.0Gbps) S Superior Return Loss and Insertion Loss for SuperSpeed Analog Switches S Low Quiescent Current: 36µA (typ) S All Link Training is Preserved (SuperSpeed) S LVCMOS Control (1.4V P VIH P 3.6V) The device features low insertion loss for all speeds. It has Q6kV Human Body Model (HBM) ESD protection on all I/O pins. In addition, the low/full/Hi-Speed COM_ ports have ESD protection to Q15kV HBM and Q8kV IEC 61000-4-2 contact. S Operation from a Single +3.3V Power Supply S Small, 3.5mm x 9.0mm, 42-Pin TQFN Package Ordering Information The device is available in a small, 3.5mm x 9.0mm, 42-pin TQFN package and is specified over the extended -40NC to +85NC temperature range. PART MAX14978ETO+ Applications TEMP RANGE PIN-PACKAGE -40NC to +85NC 42 TQFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Desktop PCs Laptop PCs Industrial USB Switching Typical Operating Circuit +3.3V USB SWITCH CONTROLLER 0.1µF SEL1 SEL2 D+ D- COMD+ COMD- SUPERSPEED Tx+ USB CONTROLLER Tx- COM0+ Rx+ COM1+ Rx- COM1- VCC NCDNOD+ NOD- MAX14978 COM0- EN VDD NCD+ GND NC0+ NC0NC1+ NC1NO0+ NO0NO1+ NO1- D+ DSUPERSPEED Tx+ USB TxPORT1 Rx+ Rx- D+ DTx+ SUPERSPEED USB TxPORT2 Rx+ Rx- ________________________________________________________________ Maxim Integrated Products 1 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. MAX14978 General Description MAX14978 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND, unless otherwise noted.) VCC. ......................................................................-0.3V to +6.0V VDD. ......................................................................-0.3V to +4.0V SEL1, EN, COMD_, NOD_, NCD_ (Note 1)....................................... -0.3V to (VCC + 0.3V) SEL2, COM0_, COM1_, NC0_, NC1_, NO0_, NO1_ (Note 1)................ -0.3V to (VDD + 0.3V) |COM0_ - NO0_|, |COM0_ - NC0_|, |COM0 _ - NO1 _|, |COM0 _ - NC1_| (Note 1)......... 0 to +2.0V Continuous Current (COM0_, COM1_ to NO0_, NO1_, NC0_, NC1_)......................... Q70mA Peak Current (COM0_, COM1_ to NO0_, NO1_, NC0_, NC1_) (pulsed at 1ms, 10% duty cycle).................................. Q70mA Continuous Current into Any Terminal............................. Q30mA Continuous Power Dissipation (TA = +70NC) TQFN (derate 35.7mW/NC above +70NC)...................2857mW Operating Temperature Range........................... -40NC to +85NC Storage Temperature Range............................. -65NC to +150NC Junction Temperature......................................................+150NC Lead Temperature (soldering, 10s).................................+300NC Soldering Temperature (reflow).......................................+260NC Note 1: Signals on SEL_, NO_, NC_, or COM_ exceeding VCC, VDD, or VGND 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 (VCC = +3.0V to +5.5V, VDD = +3.0V to +3.6V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VCC = VDD = +3.3V, TA = +25NC.) (Note 2) PARAMETER Power-Supply Range Supply Current Shutdown Supply Current, ICC SYMBOL Fault-Protection Trip Threshold MIN VDD 3.0 3.6 ICC VSEL1 = 0V or VCC, VEN = 0V VCC = 3.0V IDD VSEL2 = 0V or VDD ISHDN 0.6 VDD = 3.3V 0.1 Hi-Speed USB switches, 0V P VSEL1 P VIL or VIH P VSEL1 P VCC or 0V P VEN P VIL or VIH P VEN P VCC VCOM_, VNO_, VNC_ VFP Hi-Speed USB switches, VEN = 0V (Note 3) SuperSpeed USB switches Hi-Speed USB switches, COMD_ only, TA = +25NC RON Hi-Speed USB switches, VCC = 3.0V, VCOMD_ = 3.6V 1.5 60 Hi-Speed USB switches, switch disabled (VEN = VCC) SuperSpeed USB switches, VDD = 3.0V, ICOM_ = 15mA, VNO_ = VNC_ = 0V, 1.8V 2 MAX 5.5 Hi-Speed USB switches, VCOMD_ = 0V to VCC On-Resistance TYP 3.0 Increase in Supply Current, ICC, with VSEL1, VEN Voltage Analog Signal Range CONDITIONS VCC 0 VCC -0.3 VDD 1.2 VCC + 0.8 VCC +1 5 10 5.5 7 V FA FA 1 VCC + 0.6 UNITS FA V V I SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) (VCC = +3.0V to +5.5V, VDD = +3.0V to +3.6V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VCC = VDD = +3.3V, TA = +25NC.) (Note 2) PARAMETER SYMBOL On-Resistance Match Between Channels DRON On-Resistance Match Between Pairs of Same Channels DRON On-Resistance Flatness Off-Leakage Current On-Leakage Current RFLAT ICOM(OFF) ICOM(ON) CONDITIONS TYP MAX Hi-Speed USB switches, VCC = 3.0V, VCOMD_ = 2.0V (Notes 4, 5) 0.1 1 SuperSpeed USB switches, VDD = 3.0V, ICOM_ = 15mA, VNO_ or VNC_ = 0V (Notes 4, 5) 0.6 2 SuperSpeed USB switches, VDD = 3.0V, ICOM_ = 15mA, VNO_ or VNC_ = 0V (Notes 4, 5) 0.1 1 Hi-Speed USB switches, VCC = 3.0V, VCOMD_ = 0V to VCC (Note 6) 0.1 SuperSpeed USB switches, VDD = 3.0V, ICOM_ = 15mA, VNO_ or VNC_= 0V (Notes 5, 6) 0.06 Hi-Speed USB switches, VCC = 5.5V, VCOMD_ = 0V or 5.5V, VNOD_, VNCD_ = 5.5V or 0V SuperSpeed USB switches, VDD = 3.6V, VCOM_ = 0V, 1.8V; VNO_ or VNC_ = 1.8V, 0V Hi-Speed USB switches, VCC = 5.5V, VCOMD_ = 0V or 5.5V, VNOD_, VNCD_ = unconnected SuperSpeed USB switches, VDD = 3.6V, VCOM_ = 0V, 1.8V; VNO_ or VNC_ = VCOM_ or unconnected MIN UNITS I I I 2 -250 +250 nA -1 +1 FA -250 +250 nA -1 +1 FA AC PERFORMANCE On-Channel -3dB Bandwidth On-Loss Off-Isolation BW GLOSS VISO Hi-Speed USB switches, RL = RS = 50I, signal = 0dBm 950 1MHz < f < 100MHz -0.5 500MHz < f < 1.25GHz -1.4 Hi-Speed USB switches, VNOD_, VNCD_ = 0dBm, RL = RS = 50I, Figure 1 f = 10MHz -48 f = 250MHz -20 f = 500MHz -17 SuperSpeed USB switches, signal = 0dBm, RS = RL = 50I f = 10MHz -56 f = 1.25GHz -26 SuperSpeed USB switches, RL = RS = 50I, unbalanced MHz dB dB 3 MAX14978 ELECTRICAL CHARACTERISTICS (continued) MAX14978 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.0V to +5.5V, VDD = +3.0V to +3.6V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VCC = VDD = +3.3V, TA = +25NC.) (Note 2) PARAMETER SYMBOL CONDITIONS Hi-Speed USB switches, VNOD_, VNCD_= 0dBm, RL = RS = 50I, Figure 1 Crosstalk (Note 7) Signaling Data Rate VCT BR SuperSpeed USB switches, crosstalk between any two pairs, RS = RL = 50I, unbalanced, Figure 1 MIN TYP f = 10MHz -73 f = 250MHz -54 f = 500MHz -33 f = 50MHz -53 f = 1.25GHz -32 SuperSpeed USB switches, RS = RL = 50I MAX UNITS dB 5.0 Gbps LOGIC INPUT Input Logic-High VIH Input Logic-Low VIL 1.4 Input Leakage Current IIN SuperSpeed USB switches, VSEL2 = 0V or VDD Input Logic Hysteresis VHYST SuperSpeed USB switches 100 Hi-Speed USB switches, VNOD_ or VNCD_ = 1.5V, RL = 300I, CL = 35pF, VEN = VCC to 0V, Figure 2 20 100 Fs SuperSpeed USB switches, VNO_ or VNC_ = 1.0V, RL = 50I, Figure 2 90 250 ns VNOD_ or VNCD_ = 1.5V, RL = 300I, CL = 35pF, VEN = 0V to VCC, Figure 2 1 5 Fs SuperSpeed USB switches, VNO_ or VNC_ = 1.0V, RL = 50I, Figure 2 10 50 ns Hi-Speed USB switches, RL = RS = 50I, Figure 3 100 SuperSpeed USB switches, RL = RS = 50I 50 Hi-Speed USB switches V 0.5 V -250 +250 nA -1 +1 FA mV DYNAMIC PERFORMANCE Turn-On Time Turn-Off Time Propagation Delay tON tOFF tPLH, tPHL ps Output Skew Between Switches tSK Hi-Speed USB switches, skew between switch 1 and 2, RL = RS = 50I, Figure 3 40 ps Output Skew Between Pairs tSK1 SuperSpeed USB switches, RS = RL = 50I, unbalanced; skew between any two pairs, Figure 3 50 ps Output Skew Between Same Pair tSK2 SuperSpeed USB switches, RS = RL = 50I, unbalanced; skew between two lines on same pair, Figure 3 10 ps Fault-Protection Response Time tFP Hi-Speed USB switches, VCOMD_ = 0V to 5V step, RL = RS = 50I, VCC = 3.3V, Figure 4 4 0.5 5.0 Fs SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) (VCC = +3.0V to +5.5V, VDD = +3.0V to +3.6V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VCC = VDD = +3.3V, TA = +25NC.) (Note 2) PARAMETER Fault-Protection Recovery Time NO_ or NC_ Off-Capacitance COM_ Off-Capacitance COM_ On-Capacitance SYMBOL tFPR CNO(OFF) or CNC(OFF) CCOM(OFF) CONDITIONS MIN TYP Hi-Speed USB switches, VCOMD_ = 5V to 0V step, RL = RS = 50I, VCC = 3.3V, Figure 4 Hi-Speed USB switches, f = 1MHz, Figure 5 2 SuperSpeed USB switches, Figure 5 1 Hi-Speed USB switches, f = 1MHz, Figure 5 5.5 Hi-Speed USB switches, f = 240MHz, Figure 5 4.8 Hi-Speed USB switches, f = 1MHz, Figure 5 6.5 CCOM(ON) Hi-Speed USB switches, f = 240MHz, Figure 5 SuperSpeed USB switches, Figure 5 MAX UNITS 100 Fs pF pF 5.5 pF 2 Hi-Speed USB switches, VCOMD_ = 1VP-P, VBIAS = 1V, RL = RS = 50I, f = 20Hz to 20kHz 0.03 Human Body Model ±15 IEC 61000-4-2 Air Gap Discharge ±15 IEC 61000-4-2 Contact Discharge ±8 COM0_, COM1_ Human Body Model ±6 kV All Pins Human Body Model ±2 kV Total Harmonic Distortion Plus Noise THD+N % ESD PROTECTION COMD+, COMD- kV All devices are 100% production tested at TA = +25NC. All temperature limits are guaranteed by design. The switch turns off for voltages above VFP, protecting downstream circuits in case of a fault condition. DRON(MAX) = |RON(CH1) - RON(CH2)|. Guaranteed by design. Not production tested. Flatness is defined as the difference between the maximum and minimum value of on-resistance, as measured over specified analog-signal ranges. Note 7: Between any two switches. Note Note Note Note Note 2: 3: 4: 5: 6: 5 MAX14978 ELECTRICAL CHARACTERISTICS (continued) SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) MAX14978 Test Circuits/Timing Diagrams 0.1µF VCC VDD 0.1µF V OFF-ISOLATION = 20log OUT VIN NETWORK ANALYZER 0V OR VDD SEL_ VCC VDD NC_ MAX14978 V ON-LOSS = 20log OUT VIN 50Ω MEAS VOUT NO_ 50Ω 50Ω VIN COM_ V CROSSTALK = 20log OUT VIN REF 50Ω 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 1. Off-Isolation, On-Loss, and Crosstalk 0.1µF VDD VCC 0.1µF VDD VCC VN_ MAX14978 NO_ OR NC_ COM_ GND R (RL + LRON) VN_ = VNO_ OR VNC_ Figure 2. Switching Time 6 VIL 50% t OFF CL VOUT SWITCH OUTPUT CL INCLUDES FIXTURE AND STRAY CAPACITANCE. VOUT = VN_ t r < 5ns t f < 5ns VIH VOUT RL SEL_ LOGIC INPUT LOGIC INPUT 0V t ON 0.9 x V0UT 0.9 x VOUT SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) 0.1µF VDD VCC 0.1µF VDD VCC IN+ RS MAX14978 NO_+ OR NC_+ COM_+ OUT+ RISE-TIME PROPAGATION DELAY = tPLHX OR tPLHY FALL-TIME PROPAGATION DELAY = tPHLX OR tPHLY RL IN- RS NO_- OR NC_- COM_- tSK1 = DIFFERENCE IN PROPAGATION DELAY (RISE-FALL) BETWEEN ANY TWO PAIRS 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 3. Propagation Delay, Output Skew 7 MAX14978 Test Circuits/Timing Diagrams (continued) MAX14978 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) Test Circuits/Timing Diagrams (continued) VDD VCC VDD COM_ VCC 0.1µF +5V VCC = +3.3V 0.1µF +3V VCOMD_ 0V MAX14978 tFPR tFP SEL_ CAPACITANCE METER VFP +3V VNOD_ VIL OR VIH NC_ OR NO_ GND VNCD_ 0V Figure 4. Fault Protection Response/Recovery Time Figure 5. Channel Off-/On-Capacitance Typical Operating Characteristics (VCC = VDD = 3.3V, TA = +25NC, unless otherwise noted.) 10.0 Uls: 9995/9995 9.5 400 8.5 200 8.0 0 -200 7.0 6.0 -600 -200 -150 -100 -50 0 ps/div 50 100 150 200 TA = +25°C TA = +85°C 10 8 6 4 VCC = +3.3V 5.5 -800 8 7.5 6.5 -400 12 RON (Ω) 9.0 RON (Ω) VOLTAGE (mV) 600 14 MAXMAX14978 toc02 EYE: ALL BITS MAX14978 toc03 MAX14978 toc01 800 SUPERSPEED SWITCHES ON-RESISTANCE vs. VCOM_ (VCC = +3.3V) SUPERSPEED SWITCHES ON-RESISTANCE vs. VCOM_ EYE DIAGRAM (VCC = +3.3V, f = 2.5GHz, RS = RL = 50Ω) 5.0 2 TA = -40°C 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) -0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 VCOM_ (V) SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) SUPERSPEED HI-SPEED SWITCHES SUPPLY CURRENT vs. TEMPERATURE 30 20 0.9 0.8 VIL 0.7 10 35 TEMPERATURE (°C) 60 85 70 60 COM_ ON-LEAKAGE 50 40 30 20 COM_ OFF-LEAKAGE 10 0 10 35 60 4 3 2 1 0 85 0 1 TEMPERATURE (°C) MAX14978 toc06 3 LOW/FULL/HI-SPEED SWITCHES LOGIC-INPUT THRESHOLD vs. SUPPLY VOLTAGE 1.2 1.0 0.8 0.6 VIH VIL 0.4 2 0 3 2.8 3.8 LOGIC LEVEL (V) LOW/FULL/HI-SPEED SWITCHES FREQUENCY RESPONSE 0 -10 -20 2 0.2 ON-LOSS 4.8 SUPPLY VOLTAGE (V) LOW/FULL/HI-SPEED SWITCHES TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 1 MAX14978 toc10 RL = 600Ω -30 OFF-ISOLATION -40 THD+N (%) -15 MAGNITUDE (dB) -40 TA = -40°C VCOM_ (V) LOW/FULL/HI-SPEED SWITCHES QUIESCENT SUPPLY CURRENT vs. LOGIC LEVEL 5 1 0 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) QUIESCENT SUPPLY CURRENT (µA) MAX14978 toc07 80 TA = +25°C 0 0.5 LOW/FULL/HI-SPEED SWITCHES COM_ LEAKAGE CURRENT vs. TEMPERATURE TA = +85°C MAX14978 toc11 -15 LOGIC THRESHOLD (V) -40 3 1 MAX14978 toc08 0 4 2 0.6 10 LEAKAGE CURRENT (nA) 5 VIH MAX14978 toc09 40 1.0 6 RON (Ω) VCC = +3.3V 50 1.1 LOGIC THRESHOLD (V) 60 7 MAX14978 toc05 70 SUPPLY CURRENT (µA) 1.2 MAX14978 toc04 80 LOW/FULL/HI-SPEED SWITCHES ON-RESISTANCE vs. VCOM_ SUPERSPEED SWITCHES LOGIC-INPUT THRESHOLD vs. SUPPLY VOLTAGE -50 -60 -70 CROSSTALK 0.1 0.01 -80 -90 -100 0.001 1 10 100 FREQUENCY (MHz) 1,000 10 100 1000 10,000 100,000 FREQUENCY (Hz) 9 MAX14978 Typical Operating Characteristics (continued) (VCC = VDD = 3.3V, TA = +25NC, unless otherwise noted.) MAX14978 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) Pin Configuration NO1- NO1+ NO0- NO0+ NC1- NC1+ NC0- NC0+ VDD NOD- NCD- EN VCC SEL1 N.C. NCD+ NOD+ TOP VIEW 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 GND N.C. 39 20 VDD MAX14978 N.C. 41 19 GND EP 7 8 9 N.C. N.C. COMD+ GND N.C. COMD- N.C. SEL2 18 VDD 10 11 12 13 14 15 16 17 COM1+ 6 GND 5 VDD 4 COM0- 3 COM0+ 2 GND 1 N.C. + COM1- N.C. 42 GND N.C. 40 TQFN Pin Description PIN NAME 1, 2, 3, 6, 8, 36, 39-42 N.C. FUNCTION No Connection. Not internally connected. 4 COMD+ 5, 10, 14, 17, 19, 21 GND 7 COMD- 9 SEL2 11 COM0+ SuperSpeed USB Analog Switch 0, Common Positive Terminal 12 COM0- SuperSpeed USB Analog Switch 0, Common Negative Terminal 13, 18, 20, 30 VDD 15 COM1+ SuperSpeed USB Analog Switch 1, Common Positive Terminal 16 COM1- SuperSpeed USB Analog Switch 1, Common Negative Terminal 10 Hi-Speed USB Analog Switch, Common D+ Terminal Ground Hi-Speed USB Analog Switch, Common D- Terminal Digital Control Input for SuperSpeed USB Analog Switches Positive Supply Voltage Input for SuperSpeed USB Switches. Bypass VDD to GND with a 0.1FF ceramic capacitor as close as possible to the device. 22 NO1- SuperSpeed USB Analog Switch 1, Normally Open Negative Terminal 23 NO1+ SuperSpeed USB Analog Switch 1, Normally Open Positive Terminal 24 NO0- SuperSpeed USB Analog Switch 0, Normally Open Negative Terminal 25 NO0+ SuperSpeed USB Analog Switch 0, Normally Open Positive Terminal 26 NC1- SuperSpeed USB Analog Switch 1, Normally Closed Negative Terminal 27 NC1+ SuperSpeed USB Analog Switch 1, Normally Closed Positive Terminal 28 NC0- SuperSpeed USB Analog Switch 0, Normally Closed Negative Terminal 29 NC0+ SuperSpeed USB Analog Switch 0, Normally Closed Positive Terminal 31 NOD- Hi-Speed USB Analog Switch, Normally Open D- Terminal 32 NCD- Hi-Speed USB Analog Switch, Normally Closed D- Terminal SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) PIN NAME FUNCTION 33 EN Active-Low Enable Input for Hi-Speed USB Switches. Drive EN high to put Hi-Speed USB switches in high impedance. Drive EN low for normal operation. 34 VCC Positive-Supply Voltage Input for Hi-Speed USB Switches. Bypass VCC to GND with a 0.1FF ceramic capacitor as close as possible to the device. 35 SEL1 Digital Control Input for Hi-Speed USB Analog Switches 37 NCD+ Hi-Speed USB Analog Switch, Normally Closed D+ Terminal 38 NOD+ Hi-Speed USB Analog Switch, Normally Open D+ Terminal — EP Exposed Pad. EP is internally connected to GND. Connect EP to a large ground plane to maximize thermal performance. EP is not intended as an electrical connection point. Functional Diagram/Truth Table HI-SPEED USB SWITCHES VDD VCC MAX14978 HI-SPEED USB ANALOG SWITCHES COMD+ COMD- EN SEL1 NOD_ NCD_ COMD_ 0 0 OFF ON — 0 1 ON OFF — 1 X OFF OFF HIGH-Z SUPERSPEED USB SWITCHES NOD+ NCD+ SEL2 NO_ NOD- 0 OFF NC_ ON NCD- 1 ON OFF SEL1 EN SUPERSPEED USB ANALOG SWITCHES COM0+ NO0+ NC0+ NO0- COM0- NC0NO1+ COM1+ NC1+ NO1- COM1- NC1- SEL2 GND 11 MAX14978 Pin Description (continued) MAX14978 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) Detailed Description The MAX14978 is ideal for SuperSpeed USB and low/ full/Hi-Speed (1.5/12/480Mbps) USB switching applications. The low VIH threshold of the device permits it to be used with logic levels as low as 1.4V. The device’s Hi-Speed USB analog switches are based on a chargepump-assisted n-channel architecture and operate with 36FA (typ) quiescent current. The device features dual digital control inputs (SEL_) to switch Hi-Speed USB and SuperSpeed USB signal paths separately. Digital Control Inputs (SEL1, SEL2) The device’s provides dual digital control inputs (SEL1, SEL2) to select the signal path between the COM_ and NO_ or NC_ channels. Drive SEL1 and SEL2 rail-to-rail to minimize power consumption. See the Functional Diagram/Truth Table. Analog-Signal Levels The device’s switches are bidirectional, allowing NO_, NC_, and COM_ to be configured as either inputs or outputs. The Hi-Speed USB switches are equipped with a chargepump-assisted n-channel architecture that allows the switch to pass analog signals that exceed VCC up to the overvoltage fault-protection threshold. This allows USB signals that exceed VCC to pass, allowing compliance with USB requirements for voltage levels. The SuperSpeed USB switches accept signals on the COM_, NO_, and NC_ channels within a range of -0.1V to (VDD - 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. Overvoltage Fault Protection The device features overvoltage fault protection on COMD_. Fault protection prevents these switches from being damaged due to shorts to the USB VBUS voltage rail. Fault protection protects the switch and USB transceiver from damaging voltage levels. When voltages on COMD_ exceed the fault-protection threshold (VFP), COMD_, NCD_ and NOD_ are high impedance. 12 Enable Input The device features a shutdown mode for the Hi-Speed USB analog switches that reduces the VCC quiescent current to 0.1FA (typ) and places COMD+ and COMDin high impedance. Drive EN high to place the Hi-Speed USB analog switches in shutdown mode, and drive EN low for normal operation. Applications Information USB Switching The device’s analog switches are fully compliant with the USB 2.0 and USB 3.0 specifications. The low on-resistance and low on-capacitance of these switches make them ideal for high-performance switching applications. The device is ideal for routing USB data lines and for applications that require switching between multiple USB hosts or devices. The device’s Hi-Speed USB analog switches also feature overvoltage fault protection to guard systems against shorts to the USB VBUS voltage rail that is required for all Hi-Speed USB applications. Extended ESD Protection As with all Maxim devices, ESD protection structures are incorporated on all pins to protect against electrostatic discharges encountered during handling and assembly. COMD+ and COMD- are further protected against static electricity. Maxim’s engineers have developed state-ofthe-art structures to protect these pins against ESD up to Q15kV without damage. The ESD structures withstand high ESD in normal operation and when the device is powered down. After an ESD event, the device continues to function without latchup. The device is characterized for protection to the following limits: • Q15kV using Human Body Model • Q15kV using IEC 61000-4-2 Air Gap Discharge method • Q8kV using IEC 61000-4-2 Contact Discharge method Note: High ESD performance is only applicable to the Hi-Speed USB section of the switch. The SuperSpeed USB section is rated to Q6kV HBM. SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) Human Body Model Figure 6a shows the Human Body Model, and Figure 6b shows the current waveform it generates when discharged into a low-impedance state. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the test device through a 1.5kI resistor. IEC 61000-4-2 The main difference between tests done using the Human Body Model and IEC 61000-4-2 is higher peak current in IEC 61000-4-2. Because series resistance is lower in the IEC 61000-4-2 ESD test model (Figure 7a) the ESDwithstand voltage measured to this standard is generally RC 1MΩ CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE CS 100pF lower than that measured using the Human Body Model. Figure 7b shows the current waveform for the Q8kV IEC 61000-4-2 Level 4 ESD Contact Discharge test. The Air Gap Discharge test involves approaching the device with a charged probe. The Contact Discharge method connects the probe to the device before the probe is energized. 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 SuperSpeed USB specification. Ensure that power-supply bypass capacitors are placed as close as possible to the device. Multiple bypass capacitors are recommended. Connect all grounds and the exposed pad to large ground planes where possible. RC 50MΩ TO 100MΩ RD 1500Ω DISCHARGE RESISTANCE CHARGE-CURRENTLIMIT RESISTOR DEVICE UNDER TEST STORAGE CAPACITOR Figure 6a. Human Body ESD Test Model IP 100% 90% CS 150pF DISCHARGE RESISTANCE STORAGE CAPACITOR DEVICE UNDER TEST Figure 7a. IEC 61000-4-2 ESD Test Model I 100% 90% PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) IPEAK IR HIGHVOLTAGE DC SOURCE RD 330Ω AMPERES 36.8% 10% 0 10% 0 tRL TIME tDL CURRENT WAVEFORM Figure 6b. Human Body Current Waveform tR = 0.7ns TO 1ns 30ns t 60ns Figure 7b. IEC 61000-4-2 ESD Generator Current Waveform 13 MAX14978 ESD Test Conditions ESD performance depends on a variety of conditions. Contact Maxim for a reliability report that documents test setup, test methodology, and test results. MAX14978 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) Package Information Power-Supply Sequencing Caution: Do not exceed the absolute maximum ratings because stresses beyond the listed ratings may cause permanent damage to the device. Proper power-supply sequencing is recommended for all CMOS devices. Always apply VCC and VDD before applying analog signals, especially if the analog signals are not current limited. 14 For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 42 TQFN-EP T423590M+1 21-0181 90-0079 SuperSpeed USB Passive Switch (Low/Full/Hi/SuperSpeed) REVISION NUMBER REVISION DATE 0 9/10 Initial release — 1 4/11 Updated analog signal range specification in Electrical Characteristics 2 DESCRIPTION PAGES CHANGED 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 © 2011 Maxim Integrated Products 15 Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX14978 Revision History