DS25MB200 Dual 2.5 Gbps 2:1/1:2 CML Mux/Buffer with Transmit PreEmphasis and Receive Equalization General Description Features The DS25MB200 is a dual signal conditioning 2:1 multiplexer and 1:2 fan-out buffer designed for use in backplane redundancy applications. Signal conditioning features include input equalization and programmable output pre-emphasis that enable data communication in FR4 backplanes up to 2.5 Gbps. Each input stage has a fixed equalizer to reduce ISI distortion from board traces. All output drivers have 4 selectable steps of pre-emphasis to compensate for transmission losses from long FR4 backplanes and reduce deterministic jitter. The preemphasis levels can be independently controlled for the lineside and switch-side drivers. The internal loopback paths from switch-side input to switch-side output enable at-speed system testing. All receiver inputs and driver outputs are internally terminated with 100Ω differential terminating resistors. ■ ■ ■ ■ ■ ■ ■ ■ ■ 0.6–2.5 Gbps low jitter operation Fixed input equalization Programmable output pre-emphasis Independent switch and line side pre-emphasis controls Programmable switch-side loopback modes On-chip terminations HBM ESD rating 6 kV on all pins +3.3V supply Lead-less LLP-48 package (7mm x 7mm x 0.8mm, 0.5mm pitch) ■ —40°C to +85°C operating temperature range Applications ■ Backplane or cable driver ■ Redundancy and signal conditioning applications ■ Infiniband Functional Block Diagram 20182333 © 2007 National Semiconductor Corporation 201823 www.national.com DS25MB200 Dual 2.5 Gbps 2:1/1:2 CML Mux/Buffer with Transmit Pre-Emphasis and Receive Equalization December 6, 2007 DS25MB200 Simplified Block Diagram 20182331 www.national.com 2 DS25MB200 Connection Diagram 20182332 Order Number DS25MB200TSQ See NS Package Number NSQAV48 3 www.national.com DS25MB200 Pin Descriptions Pin Name Pin Number I/O Description LINE SIDE HIGH SPEED DIFFERENTIAL IO's LI_0+ LI_0− 6 7 I Inverting and non-inverting differential inputs of port_0 at the line side. LI_0+ and LI_0− have an internal 50Ω connected to an internal reference voltage. LO_0+ LO_0− 33 34 O Inverting and non-inverting differential outputs of port_0 at the line side. LO_0+ and LO_0− have an internal 50Ω connected to VCC. LI_1+ LI_1− 30 31 I Inverting and non-inverting differential inputs of port_1 at the line side. LI_1+ and LI_1− have an internal 50Ω connected to an internal reference voltage. LO_1+ LO_1− 9 10 O Inverting and non-inverting differential outputs of port_1 at the line side. LO_1+ and LO_1− have an internal 50Ω connected to VCC. SWITCH SIDE HIGH SPEED DIFFERENTIAL IO's SOA_0+ SOA_0− 46 45 O Inverting and non-inverting differential outputs of mux_0 at the switch_A side. SOA_0+ and SOA_0 − have an internal 50Ω connected to VCC. SOB_0+ SOB_0− 4 3 O Inverting and non-inverting differential outputs of mux_0 at the switch_B side. SOB_0+ and SOB_0 − have an internal 50Ω connected to VCC. SIA_0+ SIA_0− 40 39 I Inverting and non-inverting differential inputs to the mux_0 at the switch_A side. SIA_0+ and SIA_0 − have an internal 50Ω connected to an internal reference voltage. SIB_0+ SIB_0− 43 42 I Inverting and non-inverting differential inputs to the mux_0 at the switch_B side. SIB_0+ and SIB_0 − have an internal 50Ω connected to an internal reference voltage. SOA_1+ SOA_1− 22 21 O Inverting and non-inverting differential outputs of mux_1 at the switch_A side. SOA_1+ and SOA_1 − have an internal 50Ω connected to VCC. SOB_1+ SOB_1− 28 27 O Inverting and non-inverting differential outputs of mux_1 at the switch_B side. SOB_1+ and SOB_1 − have an internal 50Ω connected to VCC. SIA_1+ SIA_1− 16 15 I Inverting and non-inverting differential inputs to the mux_1 at the switch_A side. SIA_1+ and SIA_1 − have an internal 50Ω connected to an internal reference voltage. SIB_1+ SIB_1− 19 18 I Inverting and non-inverting differential inputs to the mux_1 at the switch_B side. SIB_1+ and SIB_1 − have an internal 50Ω connected to an internal reference voltage. I A logic low at MUX_S0 selects mux_0 to switch B. MUX_S0 is internally pulled high. Default state for mux_0 is switch A. CONTROL (3.3V LVCMOS) MUX_S0 37 MUX_S1 13 PREL_0 PREL_1 12 1 I PREL_0 and PREL_1 select the output pre-emphasis of the line side drivers (LO_0± and LO_1±). PREL_0 and PREL_1 are internally pulled high. See Table 3 for line side pre-emphasis levels. PRES_0 PRES_1 36 25 I PRES_0 and PRES_1 select the output pre-emphasis of the switch side drivers (SOA_0±, SOB_0 ±, SOA_1± and SOB_1±). PRES_0 and PRES_1 are internally pulled high. See Table 4 for switch side pre-emphasis levels. LB0A 47 I A logic low at LB0A enables the internal loopback path from SIA_0± to SOA_0±. LB0A is internally pulled high. LB0B 48 I A logic low at LB0B enables the internal loopback path from SIB_0± to SOB_0±. LB0B is internally pulled high. LB1A 23 I A logic low at LB1A enables the internal loopback path from SIA_1± to SOA_1±. LB1A is internally pulled high. LB1B 24 I A logic low at LB1B enables the internal loopback path from SIB_1± to SOB_1±. LB1B is internally pulled high. RSV 26 I Reserve pin to support factory testing. This pin can be left open, or tied to GND, or tied to GND through an external pull-down resistor. www.national.com A logic low at MUX_S1 selects mux_1 to switch B. MUX_S0 is internally pulled high. Default state for mux_1 is switch A. 4 Pin Number I/O Description 2, 8, 14, 20, 29, 35, 38, 44 P VCC = 3.3V ± 5%. Each VCC pin should be connected to the VCC plane through a low inductance path, typically with a via located as close as possible to the landing pad of the VCC pin. POWER VCC It is recommended to have a 0.01 μF or 0.1 μF, X7R, size-0402 bypass capacitor from each VCC pin to ground plane. GND 5, 11, 17, 32, 41 P Ground reference. Each ground pin should be connected to the ground plane through a low inductance path, typically with a via located as close as possible to the landing pad of the GND pin. GND DAP P Die Attach Pad (DAP) is the metal contact at the bottom side, located at the center of the LLP-48 package. It should be connected to the GND plane with at least 4 via to lower the ground impedance and improve the thermal performance of the package. parity. The DS25MB200 provides 4 steps of user-selectable pre-emphasis ranging from 0, −3, −6 and –9 dB to handle different lengths of backplane. Figure 1 shows a driver preemphasis waveform. The pre-emphasis duration is 188 ps nominal, corresponds to 0.47 bit-width at 2.5 Gbps. The preemphasis levels of switch-side and line-side can be individually programmed. The high speed inputs are self-biased to about 1.5V and are designed for AC coupling. The inputs are compatible to most AC coupling differential signals such as LVDS, LVPECL and CML. Functional Description The DS25MB200 is a signal conditioning 2:1 multiplexer and a 1:2 buffer designed to support port redundancy up to 2.5 Gbps. Each input stage has a fixed equalizer that provides equalization to compensate about 5 dB of transmission loss from a short backplane trace (about 10 inches backplane). The output driver has pre-emphasis (driver-side equalization) to compensate the transmission loss of the backplane that it is driving. The driver conditions the output signal such that the lower frequency and higher frequency pulses reach approximately the same amplitude at the end of the backplane, and minimize the deterministic jitter caused by the amplitude dis- TABLE 1. LOGIC TABLE FOR MULTIPLEX CONTROLS MUX_S0 Mux Function 0 MUX_0 select switch_B input, SIB_0±. 1 (default) MUX_0 select switch_A input, SIA_0±. MUX_S1 Mux Function 0 MUX_1 select switch_B input, SIB_1±. 1 (default) MUX_1 select switch_A input, SIA_0±. TABLE 2. LOGIC TABLE FOR LOOPBACK CONTROLS LB0A Loopback Function 0 Enable loopback from SIA_0± to SOA_0±. 1 (default) Normal mode. Loopback disabled. LB0B Loopback Function 0 Enable loopback from SIB_0± to SOB_0±. 1 (default) Normal mode. Loopback disabled. LB1A Loopback Function 0 Enable loopback from SIA_1± to SOA_1±. 1 (default) Normal mode. Loopback disabled. LB1B Loopback Function 0 Enable loopback from SIB_1± to SOB_1±. 1 (default) Normal mode. Loopback disabled. 5 www.national.com DS25MB200 Pin Name DS25MB200 TABLE 3. LINE-SIDE PRE-EMPHASIS CONTROLS PreL_[1:0] Pre-Emphasis Level in mVPP (VODB) De-Emphasis Level in mVPP (VODPE) Pre-Emphasis in dB (VODPE/VODB) Typical FR4 board trace 00 1200 1200 0 10 inches 01 1200 849.53 −3 20 inches 10 1200 600 −6 30 inches 1 1 (default) 1200 425.78 −9 40 inches TABLE 4. SWITCH-SIDE PRE-EMPHASIS CONTROLS PreS_[1:0] Pre-Emphasis Level in mVPP (VODB) De-Emphasis Level in mVPP (VODPE) Pre-Emphasis in dB (VODPE/VODB) Typical FR4 board trace 00 1200 1200 0 10 inches 01 1200 849.53 −3 20 inches 10 1200 600 −6 30 inches 1 1 (default) 1200 425.78 −9 40 inches 20182337 FIGURE 1. Driver Pre-Emphasis Differential Waveform (showing all 4 pre-emphasis steps) www.national.com 6 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VCC) CMOS/TTL Input Voltage CML Input/Output Voltage Junction Temperature Storage Temperature Lead Temperature Soldering, 4 sec Thermal Resistance, θJC-top 20.7°C/W 6 kV Recommended Operating Ratings Supply Voltage (VCC-GND) Min Typ Max Units 3.13 3.3 5 3.465 V 50 mVPP 85 °C 100 °C Supply Noise Amplitude 10 Hz to 2 GHz +260°C 33.7°C/W 18.2°C/W ESD Rating HBM, 1.5 kΩ, 100 pF −0.3V to 4V −0.3V to (VCC +0.3V) −0.3V to (VCC +0.3V) +150°C −65°C to +150°C Thermal Resistance, θJA 5.8°C/W Thermal Resistance, ΦJB Ambient Temperature –40 Case Temperature Electrical Characteristics Over recommended operating supply and temperature ranges unless otherwise specified. Symbol Parameter Conditions Min Typ (Note 2) Max Units LVCMOS DC SPECIFICATIONS VIH High Level Input Voltage 2.0 VCC +0.3 V VIL Low Level Input Voltage −0.3 0.8 V IIH High Level Input Current VIN = VCC −10 10 µA IIL Low Level Input Current VIN = GND 75 124 µA RPU Pull-High Resistance 94 35 kΩ RECEIVER SPECIFICATIONS VID Differential Input Voltage Range AC Coupled Differential Signal Below 1.25 Gbps Above 1.25 Gbps Measured at input pins. Common Mode Voltage at Receiver Inputs Measured at receiver inputs reference to ground. RITD Input Differential Termination On-chip differential termination between IN+ or IN −. RITSE Input Termination (single-end) On-chip termination IN+ or IN− to GND for frequency > 100 MHz. VICM 100 100 1750 1560 1.5 84 100 mVP-P mVP-P V 116 Ω Ω 50 DRIVER SPECIFICATIONS VODB Output Differential Voltage Swing without Pre-Emphasis RL = 100Ω ±1% PRES_1=PRES_0=0 PREL_1=PREL_0=0 Driver pre-emphasis disabled. Running K28.7 pattern at 2.5 Gbps. See Figure 5 for test circuit. 7 1000 1200 1400 mVP-P www.national.com DS25MB200 Thermal Resistance, θJC-bottom Absolute Maximum Ratings (Note 1) DS25MB200 Symbol VPE tPE Parameter Conditions Min Output Pre-Emphasis RL = 100Ω ±1% Voltage Ratio Running K28.7 pattern at 2.5 Gbps 20*log(VODPE/VODB) PREx_[1:0]=00 PREx_[1:0]=01 PREx_[1:0]=10 PREx_[1:0]=11 x=S for switch side pre-emphasis control x=L for line side pre-emphasis control See Figure 1 on waveform. See Figure 5 for test circuit. Pre-Emphasis Width Typ (Note 2) Max 0 −3 −6 −9 Units dB dB dB dB Tested at −9 dB pre-emphasis level, PREx[1:0]=11 x=S for switch side pre-emphasis control x=L for line side pre-emphasis control See Figure 4 on measurement condition. 125 188 400 ps 42 50 58 Ω ROTSE Output Termination On-chip termination from OUT+ or OUT− to VCC ROTD Output Differential Termination On-chip differential termination between OUT+ and OUT− ΔROTSE Mis-Match in Output Termination Resistors Mis-match in output terminations at OUT+ and OUT− VOCM Output Common Mode Voltage Ω 100 2.4 5 % 2.9 V 1 W POWER DISSIPATION PD Power Dissipation VDD = 3.465V All outputs terminated by 100Ω ±1%. PREL_[1:0]=0, PRES_[1:0]=0 Running PRBS 27-1 pattern at 2.5 Gbps AC CHARACTERISTICS tR tF Differential Low to High Measured with a clock-like pattern at 100 MHz, Transition Time between 20% and 80% of the differential output Differential High to Low voltage. Pre-emphasis disabled. Transition time is measured with fixture as shown Transition Time in Figure 5, adjusted to reflect the transition time at the output pins. 80 ps 80 ps tPLH Differential Low to High Measured at 50% differential voltage from input to Propagation Delay output. 0.5 2 ns tPHL Differential High to Low Propagation Delay 0.5 2 ns tSKP Pulse Skew |tPHL–tPLH| 20 ps tSKO Output Skew (Note 7) Difference in propagation delay between two outputs in the same device. 200 ps tSKPP Part-to-Part Skew Difference in propagation delay between the same output from devices operating under identical conditions. 500 ps 6 ns 2 2 psrms psrms tSM RJ Mux Switch Time Device Random Jitter (Note 5) www.national.com Measured from VIH or VIL of the mux-control or loopback control to 50% of the valid differential output. See Figure 5 for test circuit. Alternating-1-0 pattern. Pre-emphasis disabled. At 1.25 Gbps At 2.5 Gbps 8 1.8 Parameter Conditions DJ Device Deterministic Jitter (Note 6) See Figure 5 for test circuit. Pre-emphasis disabled. Between 0.8 and 2.5 Gbps with PRBS7 pattern for DS25MB200 @ –40°C to 85°C DRMAX Maximum Data Rate Tested with alternating-1-0 pattern DRMIN Minimum Data Rate Tested with 8B/10B coding Min Typ (Note 2) Max Units 30 Pspp 2.5 Gbps 0.6 Gbps Note 1: “Absolute Maximum Ratings” are the ratings 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. Note 2: Typical parameters measured at VCC = 3.3V, TA = 25°C. They are for reference purposes and are not production-tested. Note 3: IN+ and IN− are generic names refer to one of the many pairs of complimentary inputs of the DS25MB200. OUT+ and OUT− are generic names refer to one of the many pairs of the complimentary outputs of the DS25MB200. Differential input voltage VID is defined as |IN+–IN−|. Differential output voltage VOD is defined as |OUT+–OUT−|. Note 4: K28.7 pattern is a 10-bit repeating pattern of K28.7 code group {001111 1000} K28.5 pattern is a 20-bit repeating pattern of +K28.5 and −K28.5 code groups {110000 0101 001111 1010} Note 5: Device output random jitter is a measurement of the random jitter contribution from the device. It is derived by the equation sqrt(RJOUT2– RJIN2), where RJOUT is the total random jitter measured at the output of the device in psrms, RJIN is the random jitter of the pattern generator driving the device. Note 6: Device output deterministic jitter is a measurement of the deterministic jitter contribution from the device. It is derived by the equation (DJOUT–DJIN), where DJOUT is the total peak-to-peak deterministic jitter measured at the output of the device in pspp, DJIN is the peak-to-peak deterministic jitter of the pattern generator driving the device. Note 7: tSKO is the magnitude difference in the propagation delays among data paths between switch A and switch B of the same port and similar data paths between port 0 and port 1. An example is the output skew among data paths from SIA_0± to LO_0±, SIB_0± to LO_0±, SIA_1± to LO_1± and SIB_1± to LO_1 ±. Another example is the output skew among data paths from LI_0± to SOA_0±, LI_0± to SOB_0±, LI_1± to SOA_1± and LI_1± to SOB_1±. tSKO also refers to the delay skew of the loopback paths of the same port and between similar data paths between port 0 and port 1. An example is the output skew among data paths SIA_0± to SOA_0±, SIB_0± to SOB_0±, SIA_1± to SOA_1± and SIB_1± to SOB_1±. 9 www.national.com DS25MB200 Symbol DS25MB200 Timing Diagrams 20182336 FIGURE 2. Driver Output Transition Time 20182335 FIGURE 3. Propagation Delay from Input to Output 20182339 FIGURE 4. Test Condition for Output Pre-Emphasis Duration www.national.com 10 DS25MB200 20182334 FIGURE 5. AC Test Circuit The DS25MB200 input equalizer provides equalization to compensate about 5 dB of transmission loss from a short backplane transmission line. For characterization purposes, a 25-inch FR4 coupled micro-strip board trace is used in place of the short backplane link. The 25-inch microstrip board trace Trace Length Finished Trace Width W 25 inches 8.5 mil has approximately 5 dB of attenuation between 375 MHz and 1.875 GHz, representing closely the transmission loss of the short backplane transmission line. The 25-inch microstrip is connected between the pattern generator and the differential inputs of the DS25MB200 for AC measurements. Dielectric Constant Separation between Dielectric Height H Traces εR 11.5 mil 6 mil 11 3.8 Loss Tangent 0.022 www.national.com DS25MB200 Application Information 20182344 FIGURE 6. Application Diagram (showing data paths of port 0) www.national.com 12 DS25MB200 Physical Dimensions inches (millimeters) unless otherwise noted LLP-48 Package Order Number DS25MB200TSQ NS Package Number NSQAV48 13 www.national.com DS25MB200 Dual 2.5 Gbps 2:1/1:2 CML Mux/Buffer with Transmit Pre-Emphasis and Receive Equalization Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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