SY89835U 2.5V, 2GHz (3.2 Gbps) Ultra-Precision, Differential 1:2 LVDS Fanout Buffer with Internal Termination and Fail Safe Input General Description The SY89835U is a 2.5V, high-speed 2GHz differential Low Voltage Differential Swing (LVDS) 1:2 fanout buffer optimized for ultra-low skew applications. Within device skew is guaranteed to be less than 20ps over supply voltage and temperature. A unique Fail-Safe Input (FSI) protection prevents metastable conditions when no signal is present or when the selected input clock fails to a DC voltage (voltage between the pins of the differential input drops sufficiently below 100 mV). The SY89835U is part of Micrel’s high-speed clock synchronization family. For applications that require a different I/O combination, consult Micrel’s web site, and choose from a comprehensive product line of highspeed, low-skew fanout buffers, translators and clock generators. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. Functional Block Diagram Precision Edge® Features • Guaranteed AC performance over temperature and voltage: – DC-to > 3.2Gbps throughput – 210ps typical propagation delay (IN-to-Q) – <20ps within-device skew – <150ps rise/fall times • Fail Safe Input – Prevents outputs from oscillating • Ultra-low jitter design – <1psRMS cycle-to-cycle jitter – <10psPP total jitter – <1psRMS random jitter – <10psPP deterministic jitter • High-speed LVDS outputs • 2.5V ±5% power supply operation • Industrial temperature range: –40°C to +85°C • Available in 8-pin (2mm x 2mm) MLF™ package Applications • • • • Clock or data distribution SONET clock or data distribution Fibre Channel clock or data distribution Gigabit Ethernet clock or data distribution Markets • • • • • DataCom Telecom Storage ATE Precision test and measurement Precision Edge is a registered trademark of Micrel, Inc. MLF and MicroLeadFrame are trademarks of Amkor Technology, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com February 2006 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U Ordering Information(1) Part Number Package Type Operating Range Package Marking Lead Finish SY89835UMG MLF-8 Industrial 835 with Pb-Free bar-line indicator NiPdAu Pb-Free SY89835UMGTR(2) MLF-8 Industrial 835 with Pb-Free bar-line indicator NiPdAu Pb-Free Notes: 1. Contact factory for die availability. Dice are guaranteed at TA = 25°C, DC Electricals only. 2. Tape and Reel. Pin Configuration 8-Pin MLF™ (MLF-8) Pin Description Pin Number Pin Name Pin Function 1 VCC Positive Power Supply: Bypass with 0.1µF//0.01µF low ESR capacitor and place as close to VCC pin as possible. Power supply tolerance is ±5%. 2, 3 IN, /IN Differential Inputs: This input pair is the differential signal input to the device. Input accepts DC-Coupled differential signals as small as 100mV (200mVPP). The input is internally terminated with 100Ω between IN and /IN. If the input swing falls below a certain threshold (typically 30mV), the Fail Safe Input (FSI) feature will guarantee a stable output by latching the output to its last valid state. Please refer to the “Input Interface Applications” section for more details. 4 GND 5, 6 7, 8 /Q1, Q1 /Q0, Q0 Ground. GND pins and exposed pad must be connected to the most negative potential of the device ground. Differential Outputs (LVDS): Normally terminated with 100Ω across the pair (Q, /Q). See “LVDS Outputs” section, Figure 2a. Truth Table IN /IN Q /Q 0 1 0 1 1 0 1 0 February 2006 2 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VCC) ............................... –0.5V to +4.0V Input Voltage (VIN) ............................ –0.5V to VCC +0.3V LVDS Output Current (IOUT)..................................±10mA Input Current Source or Sink Current on (IN, /IN) ...............±50mA Lead Temperature (soldering, 20sec.) .................. 260°C Storage Temperature (Ts) ....................–65°C to +150°C Supply Voltage (VIN)...................... +2.375V to +2.635V Ambient Temperature (TA) ................... –40°C to +85°C Package Thermal Resistance(3) MLF™ Still-air (θJA) ........................................... 93°C/W Junction-to-board (ψJB) ......................... 32°C/W DC Electrical Characteristics(4) TA = –40°C to +85°C, unless otherwise stated. Symbol Parameter Condition Min Typ Max Units 2.375 2.5 2.625 V 50 70 mA 100 110 Ω VCC Power Supply Voltage Range ICC Power Supply Current RDIFF_IN Differential Input Resistance (IN-to-/IN) 90 VIH Input HIGH Voltage (IN, /IN) 1.2 VCC V VIL Input LOW Voltage (IN, /IN) 0 VIH–0.1 V VIN Input Voltage Swing (IN, /IN) see Figure 2c 0.1 VCC V VDIFF_IN Differential Input Voltage Swing (|IN - /IN|) see Figure 2d 0.2 VIN_FSI Input Voltage Threshold that Triggers FSI No load, max. VCC V 30 100 mV Max Units LVDS Outputs DC Electrical Characteristics(4) VCC = +2.5V ±5%, RL = 100Ω across the outputs; TA = –40°C to +85°C, unless otherwise stated. Symbol Parameter Condition Min Typ VOUT Output Voltage Swing See Figure 2c 250 325 mV VDIFF_OUT Differential Output Voltage Swing See Figure 2d 500 650 mV VOCM Output Common Mode Voltage 1.125 1.20 ∆VOCM Change in Common Mode Voltage 1.275 V 50 mV –50 Notes: 1. Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum ratings conditions for extended periods may affect device reliability. 2. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings. 3. Package thermal resistance assumes exposed pad is soldered (or equivalent) to the device's most negative potential on the PCB. ψJB and θJA values are determined for a 4-layer board in still-air number, unless otherwise stated. 4. The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established. February 2006 3 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U AC Electrical Characteristics(5) VCC = +2.5V ±5%, RL = 100Ω across the outputs; TA = –40°C to +85°C, unless otherwise stated. Symbol Parameter Condition fMAX Maximum Frequency VOUT > 200mV tPD Propagation Delay IN-to-Q Min tJitter Units Clock 2.0 3.0 150 300 500 100 210 400 5 20 ps 200 ps VIN: 100mV-200mV Gbps GHz ps Within Device Skew Note 6 Part-to-Part Skew Note 7 Data Random Jitter Note 8 1 psRMS Deterministic Jitter Note 9 10 psPP Cycle-to-Cycle Jitter Note 10 1 psRMS Clock Total Jitter tr, tf Max 3.2 > 200mV tSkew Typ NRZ Data Note 11 Output Rise/Fall Times (20% to 80%) At full output swing. 40 Duty Cycle Differential I/O 47 75 10 psPP 150 ps 53 % Notes: 5. High-frequency AC parameters are guaranteed by design and characterization. 6. Within device skew is measured between two different outputs under identical input transitions. 7. Part-to-part skew is defined for two parts with identical power supply voltages at the same temperature and no skew at the edges at the respective inputs. 8. Random jitter is measured with a K28.7 pattern, measured at ≤ fMAX. 9. Deterministic jitter is measured at 2.5Gbps with both K28.5 and 2 –1 PRBS pattern. 23 10. Cycle-to-cycle jitter definition: the variation period between adjacent cycles over a random sample of adjacent cycle pairs. tJITTER_CC = Tn –Tn+1, where T is the time between rising edges of the output signal. 12 11. Total jitter definition: with an ideal clock input frequency of ≤ fMAX (device), no more than one output edge in 10 output edges will deviate by more than the specified peak-to-peak jitter value. February 2006 4 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U metastable condition and guarantee a stable output signal. No ringing and no undetermined state will occur at the output under these conditions. Please note that the FSI function will not prevent duty cycle distortion in case of a slowly deteriorating (but still toggling) input signal. Due to the FSI function, the propagation delay will depend upon the rise and fall time of the input signal and on its amplitude. Refer to “Typical Operating Characteristics” for detailed information. Functional Description Fail-Safe Input (FSI) The input includes a special failsafe circuit to sense the amplitude of the input signal and to latch the outputs when there is no input signal present, or when the amplitude of the input signal drops sufficiently below 100mVPK (200mVPP). Input Clock Failure Case If the input clock fails to a floating, static, or extremely low signal swing, the FSI function will eliminate a Timing Diagrams February 2006 5 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U Typical Characteristics VCC = 2.5V, GND = 0V, VIN = 100mV, RL = 100Ω across the outputs, TA = 25°C, unless otherwise stated. February 2006 6 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U Functional Characteristics VCC = 2.5V, GND = 0V, VIN = 100mV, RL = 100Ω across the outputs, TA = 25°C, unless otherwise stated. February 2006 7 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U Input Stage Figure 2a. LVDS Differential Measurement Figure 1. Simplified Differential Input Buffer LVDS Outputs LVDS specifies a small swing of 325mV typical, on a nominal 1.20V common mode above ground. The common mode voltage has tight limits to permit large variations in ground noise between an LVDS driver and receiver. These outputs can drive AC- or DCcoupled differential signals. The SY89835U can drive long lengths of coaxial cables and FR4 traces. Table 1 below shows typical lengths of cables driven at different clock and data rates. Clock/Data Rate Coaxial Cable (1) Length FR4 Cable Length(2) 100MHz 4.5m 1.40m 622MHz 3.5m 0.85m 1.25Gbps 3.8m 0.80m 2.50Gbps 3.3m 0.50m Figure 2b. LVDS Common Mode Measurement Figure 2c. Single-Ended Swing Table 1. Typical Lengths of Coaxial and FR4 Traces Notes: 1. Specifications for the center conductor of the coaxial cables used are “19 1/19 spcw OD .037 inch ± 0.001”. These are 1m cables, p/n SB-142 manufactured by Harbour Industries. www.harbourind.com. 2. The FR4 traces are 6.25mil wide and 6mil thick. Horizontal distance between adjacent traces is 7.75mil. These traces are fabricated on a Molex GBX Reference Backplane. www.molex.com. February 2006 Figure 2d. Differential Swing 8 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U Input Interface Applications Figure 3. LVDS Input Interface Related Product and Support Documents Part Number Function Data Sheet Link SY89542U 2.5V, 3.2Gbps Dual, Differential 2:1 LVDS Multiplexer with Internal Termination http://www.micrel.com/_PDF/HBW/sy89542u.pdf SY89543L 3.3V, 3.2Gbps Dual, Differential 2:1 LVDS Multiplexer with Internal Termination http://www.micrel.com/_PDF/HBW/sy89543u.pdf SY89544U 2.5V, 3.2Gbps Differential 4:1 LVDS Multiplexer with Internal Input Termination http://www.micrel.com/_PDF/HBW/sy89544u.pdf MLF™ Manufacturing Guidelines Exposed Pad Application Notes http://www.amkor.com/products/notespapers/MLF_appnote_0301.pdf New Products and Termination Application Notes http://www.micrel.com/product-info/products/sy89830u.shtml HBW Solutions February 2006 9 M9999-020706 [email protected] or (408) 955-1690 Micrel, Inc. SY89835U Package Information 8-Pin MLF™ (MLF-8) MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2006 Micrel, Incorporated. February 2006 10 M9999-020706 [email protected] or (408) 955-1690