SY58604U 3.2Gbps Precision, LVPECL Buffer with Internal Termination and Fail Safe Input General Description The SY58604U is a 2.5/3.3V, high-speed, fully differential LVPECL buffer optimized to provide less than 10pspp total jitter. The SY58604U can process clock signals as fast as 2.5GHz or data patterns up to 3.2Gbps. The differential input includes Micrel’s unique, 3-pin input termination architecture that interfaces to LVPECL, LVDS or CML differential signals, (AC- or DC-coupled) as small as 100mV (200mVpp) without any level-shifting or termination resistor networks in the signal path. For AC-coupled input interface applications, an integrated voltage reference (VREF-AC) is provided to bias the VT pin. The output is 800mV LVPECL, with extremely fast rise/fall times guaranteed to be less than 110ps. The SY58604U operates from a 2.5V ±5% supply or 3.3V ±10% supply and is guaranteed over the full industrial temperature range (–40°C to +85°C). For applications that require CML or LVDS outputs, consider the SY58603U and the SY58605U, buffers with 400mV and 325mV output swings respectively. The SY58604U ® is part of Micrel’s high-speed, Precision Edge product line. Datasheets and support documentation can be found on Micrel’s web site at: www.micrel.com. Functional Block Diagram ® Precision Edge Features ∑ Precision 800mV LVPECL buffer ∑ Guaranteed AC performance over temperature and voltage: – DC-to > 3.2Gbps throughput – <350ps typical propagation delay (IN-to-Q) – <110ps rise/fall times ∑ Fail Safe Input – Prevents output from oscillating when input is invalid ∑ Ultra-low jitter design – <1psRMS cycle-to-cycle jitter – <10psPP total jitter – <1psRMS random jitter – <10psPP deterministic jitter ∑ High-speed LVPECL output ∑ 2.5V ±5% or 3.3V ±10% power supply operation ∑ Industrial temperature range: –40°C to +85°C ∑ Available in 8-pin (2mm x 2mm) DFN package Applications ∑ ∑ ∑ ∑ All SONET clock and data distribution Fibre Channel clock and data distribution Gigabit Ethernet clock and data distribution Backplane distribution Markets ∑ ∑ ∑ ∑ ∑ ∑ ∑ Storage ATE Test and measurement Enterprise networking equipment High-end servers Access Metro area network equipment Precision Edge is a registered trademark of Micrel, 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 April 2008 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Ordering Information(1) Part Number Package Type Operating Range Package Marking Lead Finish SY58604UMG DFN-8 Industrial 604 with Pb-Free bar-line indicator NiPdAu Pb-Free DFN-8 Industrial 604 with Pb-Free bar-line indicator NiPdAu Pb-Free SY58604UMGTR (2) 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 DFN Pin Description Pin Number Pin Name 1, 4 IN, /IN Differential Input: This input pair is the differential signal input to the device. Input accepts DC-Coupled differential signals as small as 100mV (200mVpp). Each pin of this pair internally terminates with 50_ to the VT pin. If the input swing falls below a certain threshold (typical 30mV), the Fail Safe Input (FSI) feature will guarantee a stable output by latching the output to its last valid state. See “Input Interface Applications” subsection for more details. 2 VT Input Termination Center-Tap: Each input terminates to this pin. The VT pin provides a center-tap for each input (IN, /IN) to a termination network for maximum interface flexibility. See “Input Interface Applications” subsection. 3 VREF-AC 5 GND, Exposed pad 6, 7 /Q, Q LVPECL Differential Output Pair: Differential buffered output copy of the input signal. The output swing is typically 800mV. See “LVPECL Output Termination” subsection. 8 VCC Positive Power Supply: Bypass with 0.1µF//0.01µF low ESR capacitors as close to the VCC pin as possible. April 2008 Pin Function Reference Voltage: This output biases to VCC–1.2V. It is used for AC-coupling inputs IN and /IN. Connect VREF-AC directly to the VT pin. Bypass with 0.01µF low ESR capacitor to VCC. Maximum sink/source current is ±1.5mA. See “Input Interface Applications” subsection for more details. Ground: Exposed pad must be connected to a ground plane that is the same potential as the ground pin. 2 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VCC) ................................. –0.5V to +4.0V Input Voltage (VIN) ............................... –0.5V to VCC+0.5V LVPECL Output Current (IOUT) Continuous ......................................................... 50mA Surge................................................................ 100mA Current (VT) Source or sink on VT pin ............................... ±100mA Input Current Source or sink Current on (IN, /IN) ................. ±50mA Current (VREF) (4) Source or sink current on VREF-AC ............. ±1.5mA Maximum Operating Junction Temperature............125°C Lead Temperature (soldering, 20sec.) ....................260°C Storage Temperature (Ts) ...................... –65°C to +150°C Supply Voltage (VIN) .......................... +2.375V to +3.60V Ambient Temperature (TA) ..................... –40°C to +85°C (3) Package Thermal Resistance DFN Still-air (qJA) .............................................. 93°C/W Junction-to-board (YJB)............................ 56°C/W DC Electrical Characteristics(5) TA = –40°C to +85°C, unless otherwise stated. Symbol Parameter VCC Power Supply Voltage Range Condition ICC Power Supply Current RDIFF_IN Differential Input Resistance (IN-to-/IN) VIH Input HIGH Voltage (IN, /IN) IN, /IN, Note 7 VIL Input LOW Voltage (IN, /IN) IN, /IN VIN Input Voltage Swing (IN, /IN) see Figure 3a, Note 6 VDIFF_IN Differential Input Voltage Swing (|IN - /IN|) see Figure 3b VIN_FSI Input Voltage Threshold that Triggers FSI VREF-AC Output Reference Voltage VT_IN Voltage from Input to VT Min Typ Max Units 2.375 2.5 2.625 V 3.0 3.3 3.6 30 45 mA 100 110 Ω VCC–1.6 VCC V 0 VIH–0.1 V 0.1 1.7 V No load, max. VCC 90 0.2 VCC–1.3 V 30 100 mV VCC–1.2 VCC–1.1 V 1.28 V 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. YJB and qJA values are determined for a 4-layer board in still-air number, unless otherwise stated. 4. Due to the limited drive capability, use for input of the same package only. 5. The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established. 6. VIN (max) is specified when VT is floating. 7. VIH (min) not lower than 1.2V. April 2008 3 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U LVPECL Outputs DC Electrical Characteristics(5) VCC = +2.5V ±5% or +3.3V ±10%, RL = 50Ω to VCC-2V; TA = –40°C to +85°C, unless otherwise stated. Symbol Parameter Max Units VOH Output HIGH Voltage VCC-1.145 VCC -0.895 V VOL Output LOW Voltage VCC-1.945 VCC-1.695 V VOUT Output Voltage Swing See Figure 3a 550 800 950 mV VDIFF_OUT Differential Output Voltage Swing See Figure 3b 1100 1600 April 2008 Condition Min 4 Typ mV M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U AC Electrical Characteristics VCC = +2.5V ±5% or +3.3V ±10%, RL = 50Ω to VCC-2V, Input tr/tf: <300ps; TA = –40°C to +85°C, unless otherwise stated. Symbol Parameter Condition Min Typ fMAX Maximum Frequency NRZ Data 3.2 4.25 Gbps 2.5 3 GHz VIN: 100mV-200mV 180 320 450 ps VIN: 200mV-800mV 150 230 350 ps VOUT > 400mV tPD Propagation Delay IN-to-Q Clock Max Units tSkew Part-to-Part Skew Note 7 135 ps tJitter Data Random Jitter Note 8 1 psRMS Deterministic Jitter Note 9 10 psPP Clock Cycle-to-Cycle Jitter Note 10 1 psRMS Total Jitter Note 11 10 psPP 110 ps 53 % tr, tf Output Rise/Fall Times (20% to 80%) At full output swing. Duty Cycle Differential I/O 40 75 47 Notes: 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. April 2008 5 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Functional Description Input Clock Failure Case If the input clock fails to a floating, static, or extremely low signal swing, then the FSI function will eliminate a metastable condition and guarantee a stable output. No ringing and no undetermined state will occur at the output under these conditions. 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 on rise and fall time of the input signal and on its amplitude. Refer to “Typical Characteristics” for detailed information. 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), typically 30mVPK. Maximum frequency of SY58604U is limited by the FSI function. Timing Diagrams Figure 1a. Propagation Delay Figure 1b. Fail Safe Feature April 2008 6 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Typical Characteristics VCC = 3.3V, GND = 0V, VIN = 100mV, RL = 50Ω to VCC-2V, TA = 25°C, unless otherwise stated. April 2008 7 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Functional Characteristics 23 VCC = 3.3V, GND = 0V, VIN = 400mV, Data Pattern: 2 -1, RL = 50Ω to VCC-2V, TA = 25°C, unless otherwise stated. April 2008 8 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Functional Characteristics (continued) VCC = 3.3V, GND = 0V, VIN = 400mV, RL = 50Ω to VCC-2V, TA = 25°C, unless otherwise stated. April 2008 9 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Input and Output Stage Figure 2b. Simplified LVPECL Output Buffer Figure 2a. Simplified Differential Input Buffer Single-Ended and Differential Swings Figure 3b. Differential Voltage Swing Figure 3a. Single-Ended Voltage Swing April 2008 10 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Input Interface Applications Figure 4a. CML Interface (DC-Coupled) Figure 4b. CML Interface (AC-Coupled) Figure 4c. LVPECL Interface (DC-Coupled) Option: May connect VT to VCC Figure 4d. LVPECL Interface (AC-Coupled) April 2008 Figure 4e. LVDS Interface 11 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U LVPECL Output Termination LVPECL outputs have very low output impedance (open emitter), and small signal swing which results in low EMI. LVPECL is ideal for driving 50Ω-and-100Ωcontrolled impedance transmission lines. There are several techniques in terminating the LVPECL output, as shown in Figure 5a and 5b. Figure 5b. Three-Resistor “Y-Termination” Figure 5a. Parallel Termination-Thevenin Equivalent Related Product and Support Documents Part Number Function Data Sheet Link SY58603U 4.25Gbps Precision CML Buffer with Internal Termination and Fail Safe Input http://www.micrel.com/page.do?page=/productinfo/products/sy58603u.shtml SY58605U 3.2Gbps Precision LVDS Buffer with Internal Termination and Fail Safe Input http://www.micrel.com/page.do?page=/productinfo/products/sy58605u.shtml HBW Solutions New Products and Termination Application Notes http://www.micrel.com/page.do?page=/productinfo/as/HBWsolutions.shtml April 2008 12 M9999-041508-C [email protected] or (408) 955-1690 Micrel, Inc. SY58604U Package Information 8-Pin (2mm x 2mm) DFN 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. April 2008 13 M9999-041508-C [email protected] or (408) 955-1690