DS90LV110AT 1 to 10 LVDS Data/Clock Distributor with Failsafe General Description Features DS90LV110A is a 1 to 10 data/clock distributor utilizing LVDS (Low Voltage Differential Signaling) technology for low power, high speed operation. Data paths are fully differential from input to output for low noise generation and low pulse width distortion. The design allows connection of 1 input to all 10 outputs. LVDS I/O enable high speed data transmission for point-to-point interconnects. This device can be used as a high speed differential 1 to 10 signal distribution / fanout replacing multi-drop bus applications for higher speed links with improved signal quality. It can also be used for clock distribution up to 200MHz. The DS90LV110A accepts LVDS signal levels, LVPECL levels directly or PECL with attenuation networks. The LVDS outputs can be put into TRI-STATE by use of the enable pin. For more details, please refer to the Application Information section of this datasheet. ■ Low jitter 400 Mbps fully differential data path ■ 145 ps (typ) of pk-pk jitter with PRBS = 223−1 data pattern Connection Diagram Block Diagram ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ at 400 Mbps Single +3.3 V Supply Balanced output impedance Output channel-to-channel skew is 35ps (typ) Differential output voltage (VOD) is 320mV (typ) with 100Ω termination load. LVDS receiver inputs accept LVPECL signals LVDS input failsafe Fast propagation delay of 2.8 ns (typ) Receiver open, shorted, and terminated input failsafe 28 lead TSSOP package Conforms to ANSI/TIA/EIA-644 LVDS standard 20098201 20098205 Order Number DS90LV110ATMT See NS Package Number MTC28 © 2007 National Semiconductor Corporation 200982 www.national.com DS90LV110AT 1 to 10 LVDS Data/Clock Distributor with Failsafe October 2007 DS90LV110AT 28L TSSOP Package Derating 28L TSSOP Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. 1.209 W 9.67 mW/°C above +25°C θJA 28L TSSOP ESD Rating: Supply Voltage (VDD-VSS) −0.3V to +4V LVCMOS/LVTTL Input Voltage −0.3V to (VCC + 0.3V) (EN) LVDS Receiver Input Voltage (IN+, IN−) −0.3V to +4V LVDS Driver Output Voltage (OUT+, OUT−) −0.3V to +4V Junction Temperature +150°C Storage Temperature Range −65°C to +150°C Lead Temperature (Soldering, 4 sec.) +260°C Maximum Package Power Dissipation at 25°C 103.4 °C/Watt > 8 kV (HBM, 1.5kΩ, 100pF) > 250 V (EIAJ, 0Ω, 200pF) Recommended Operating Conditions Supply Voltage (VDD - VSS) Receiver Input Voltage Operating Free Air Temperature Min Typ Max Units 3.0 3.3 3.6 V 0 VDD V -40 +25 +85 °C Electrical Characteristics Over recommended operating supply and temperature ranges unless otherwise specified Symbol Parameter Conditions Min Typ Max Units LVCMOS/LVTTL DC SPECIFICATIONS (EN) VIH High Level Input Voltage 2.0 VDD V VIL Low Level Input Voltage VSS 0.8 V IIH High Level Input Current VIN = 3.6V or 2.0V; VDD = 3.6V ±7 ±20 μA IIL Low Level Input Current VIN = 0V or 0.8V; VDD = 3.6V ±7 ±20 μA VCL Input Clamp Voltage ICL = −18 mA −0.8 −1.5 V LVDS OUTPUT DC SPECIFICATIONS (OUT1, OUT2, OUT3, OUT4, OUT5, OUT6, OUT7, OUT8, OUT9, OUT10) VOD Differential Output Voltage RL = 100Ω 250 320 450 mV RL = 100Ω, VDD = 3.3V, TA = 25°C 260 320 425 mV 35 |mV| ΔVOD Change in VOD between Complimentary Output States VOS Offset Voltage (Note 3) ΔVOS Change in VOS between Complimentary Output States IOZ Output TRI-STATE Current 1.125 EN = 0V, 1.25 1.375 V 35 |mV| ±1 ±10 μA VOUT = VDD or GND IOFF Power-Off Leakage Current VDD = 0V; VOUT = 3.6V or GND ±1 ±10 μA ISA,ISB Output Short Circuit Current VOUT+ OR VOUT− = 0V or VDD 12 24 |mA| ISAB Both Outputs Shorted (Note 4) VOUT+ = VOUT− 6 12 |mA| 0 +100 mV LVDS RECEIVER DC SPECIFICATIONS (IN) VTH Differential Input High Threshold VCM = +0.05V or +1.2V or +3.25V, VTL Differential Input Low Threshold VDD = 3.3V −100 VCMR Common Mode Voltage Range VID = 100mV, VDD = 3.3V 0.05 3.25 V IIN Input Current VIN = +3.0V, VDD = 3.6V or 0V ±1 ±10 μA VIN = 0V, VDD = 3.6V or 0V ±1 ±10 μA www.national.com 2 0 mV Parameter Conditions Min Typ Max Units 125 160 mA No Load, 200 MHz, EN = High 80 125 mA EN = Low 15 29 mA SUPPLY CURRENT ICCD Total Supply Current RL = 100Ω, CL = 5 pF, 200 MHz, EN = High ICCZ TRI-STATE Supply Current Note 1: “Absolute Maximum Ratings” are these beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device should be operated at these limits. The table of “Electrical Characteristics” provides conditions for actual device operation. Note 2: All typical are given for VCC = +3.3V and TA = +25°C, unless otherwise stated. Note 3: VOS is defined as (VOH + VOL) / 2. Note 4: Only one output can be shorted at a time. Don't exceed the package absolute maximum rating. AC Electrical Characteristics Over recommended operating supply and temperature ranges unless otherwise specified. Symbol Parameter Conditions Min Typ Max Units TLHT Output Low-to-High Transition Time, 20% to 80%, Figure 4 (Note 5) 390 550 ps THLT Output High-to-Low Transition Time, 80% to 20%, Figure 4 (Note 5) 390 550 ps TDJ LVDS Data Jitter, Deterministic (Peak-toPeak)(Note 6) VID = 300mV; PRBS=223-1 data; VCM = 1.2V at 400 Mbps (NRZ) 145 ps TRJ LVDS Clock Jitter, Random (Note 6) VID = 300mV; VCM = 1.2V at 200 MHz clock 2.8 ps TPLHD Propagation Low to High Delay, Figure 5 2.2 2.8 3.6 ns TPHLD Propagation High to Low Delay, Figure 5 2.2 2.8 3.9 ns TSKEW Pulse Skew |TPLHD - TPHLD| (Note 5) 20 340 ps TCCS Output Channel-to-Channel Skew, Figure 6 (Note 5) 35 91 ps TPHZ Disable Time (Active to TRI-STATE) High to Z, Figure 1 3.0 6.0 ns TPLZ Disable Time (Active to TRI-STATE) Low to Z, Figure 1 1.8 6.0 ns TPZH Enable Time (TRI-STATE to Active) Z to High, Figure 1 10.0 23.0 ns TPZL Enable Time (TRI-STATE to Active) Z to Low, Figure 1 7.0 23.0 ns Note 5: The parameters are guaranteed by design. The limits are based on statistical analysis of the device performance over PVT (process, voltage and temperature) range. Note 6: The measurement used the following equipment and test setup: HP8133A pattern/pulse generator), 5 feet of RG-142 cable with DUT test board and HP83480A (digital scope mainframe) with HP83484A (50GHz scope module). The HP8133A with the RG-142 cable exhibit a TDJ = 26ps and TRJ = 1.3 ps 3 www.national.com DS90LV110AT Symbol DS90LV110AT AC Timing Diagrams 20098204 FIGURE 1. Output active to TRI-STATE and TRI-STATE to active output time 20098215 FIGURE 2. LVDS Driver TRI-STATE Circuit 20098206 FIGURE 3. LVDS Output Load 20098209 FIGURE 4. LVDS Output Transition Time www.national.com 4 DS90LV110AT 20098207 FIGURE 5. Propagation Delay Low-to-High and High-to-Low 20098208 FIGURE 6. Output 1 to 10 Channel-to-Channel Skew 5 www.national.com DS90LV110AT DS90LV110A Pin Descriptions Pin Name # of Pin Input/Output IN+ 1 I Non-inverting LVDS input Description IN - 1 I Inverting LVDS input OUT+ 10 O Non-inverting LVDS Output OUT - 10 O Inverting LVDS Output EN 1 I This pin has an internal pull-down when left open. A logic low on the Enable puts all the LVDS outputs into TRISTATE and reduces the supply current. VSS 3 P Ground (all ground pins must be tied to the same supply) VDD 2 P Power Supply (all power pins must be tied to the same supply) value and placement of external bypass capacitors less critical. External bypass capacitors should include both RF ceramic and tantalum electrolytic types. RF capacitors may use values in the range 0.01 µF to 0.1 µF. Tantalum capacitors may be in the range 2.2 µF to 10 µF. Voltage rating for tantalum capacitors should be at least 5X the power supply voltage being used. It is recommended practice to use two vias at each power pin of the DS90LV110A as well as all RF bypass capacitor terminals. Dual vias reduce the interconnect inductance by up to half, thereby reducing interconnect inductance and extending the effective frequency range of the bypass components. The outer layers of the PCB may be flooded with additional ground plane. These planes will improve shielding and isolation as well as increase the intrinsic capacitance of the power supply plane system. Naturally, to be effective, these planes must be tied to the ground supply plane at frequent intervals with vias. Frequent via placement also improves signal integrity on signal transmission lines by providing short paths for image currents which reduces signal distortion. The planes should be pulled back from all transmission lines and component mounting pads a distance equal to the width of the widest transmission line or the thickness of the dielectric separating the transmission line from the internal power or ground plane(s) whichever is greater. Doing so minimizes effects on transmission line impedances and reduces unwanted parasitic capacitances at component mounting pads. There are more common practices which should be followed when designing PCBs for LVDS signaling. Please see Application Note: AN-1108 for additional information. Application Information INPUT FAIL-SAFE The receiver inputs of the DS90LV110A have internal fail-safe biasing for short, open, and teminated input conditions. LVDS INPUTS TERMINATION The LVDS Receiver input must have a 100Ω termination resistor placed as close as possible across the input pins. UNUSED CONTROL INPUTS The EN control input pin has internal pull down device. If left open, the 10 outputs will default to TRI-STATE. EXPANDING THE NUMBER OF OUTPUT PORTS To expand the number of output ports, more than one DS90LV110A can be used. Total propagation delay through the devices should be considered to determine the maximum expansion. Adding more devices will increase the output jitter due to each pass. PCB LAYOUT AND POWER SYSTEM BYPASS Circuit board layout and stack-up for the DS90LV110A should be designed to provide noise-free power to the device. Good layout practice also will separate high frequency or high level inputs and outputs to minimize unwanted stray noise pickup, feedback and interference. Power system performance may be greatly improved by using thin dielectrics (4 to 10 mils) for power/ground sandwiches. This increases the intrinsic capacitance of the PCB power system which improves power supply filtering, especially at high frequencies, and makes the www.national.com 6 The DS90LV110A accepts differential signals and allow simple AC or DC coupling. With a wide common mode range, the DS90LV110A can be DC-coupled with all common differential drivers (i.e. LVPECL, LVDS, CML). The following three figures illustrate typical DC-coupled interface to common differential drivers. 20098241 Typical LVDS Driver DC-Coupled Interface to DS90LV110A Input 20098242 Typical CML Driver DC-Coupled Interface to DS90LV110A Input 20098243 Typical LVPECL Driver DC-Coupled Interface to DS90LV110A Input 7 www.national.com DS90LV110AT INPUT INTERFACING DS90LV110AT OUTPUT INTERFACING The DS90LV110A outputs signals that are compliant to the LVDS standard. Their outputs can be DC-coupled to most common differential receivers. The following figure illustrates typical DC-coupled interface to common differential receivers and assumes that the receivers have high impedance inputs. While most differential receivers have a common mode input range that can accomodate LVDS compliant signals, it is recommended to check respective receiver's data sheet prior to implementing the suggested interface implementation. 20098244 Typical DS90LV110A Output DC-Coupled Interface to an LVDS, CML or LVPECL Receiver www.national.com 8 DS90LV110AT Multi-Drop Applications 20098202 Point-to-Point Distribution Applications 20098203 For applications operating at data rate greater than 400Mbps, a point-to-point distribution application should be used. This improves signal quality compared to multi-drop applications due to no stub PCB trace loading. The only load is a receiver at the far end of the transmission line. Point-to-point distribution applications will have a wider LVDS bus lines, but data rate can increase well above 400Mbps due to the improved signal quality. 9 www.national.com DS90LV110AT Typical Performance Characteristics Output Voltage (VOD) vs. Resistive Load (RL) Peak-to-Peak Output Jitter at VCM = +0.4V vs. VID 20098212 20098211 Peak-to-Peak Output Jitter at VCM = +1.2V vs. VID Peak-to-Peak Output Jitter at VCM = +2.9V vs. VID 20098213 www.national.com 20098214 10 DS90LV110AT Physical Dimensions inches (millimeters) unless otherwise noted NS Package Number MTC28 Order Number DS90LV110ATMT (Rail quantity of 48) DS90LV110ATMTX (2500 piece Tape and Reel) 11 www.national.com DS90LV110AT 1 to 10 LVDS Data/Clock Distributor with Failsafe Notes THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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