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SM802108 clockworks ? 10gbe & gbe (156.25mhz, 125mhz) ultra-low jitter, lvpecl frequency synthesizer clockworks is a trademark of micrel, inc rotarywave is a registered trademark of multigig, 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 january 2011 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 general description the SM802108 is a member of the clockworks ? family of devices from micrel and provides an extremely low-noise timing solution for gbe and 10gbe ethernet clock signals. it is based upon a unique patented rotarywave ? architecture that provides very low phase noise. the device operates from a 3.3v or 2.5v power supply and synthesizes two lvpecl output clocks at 156.25mhz and another two at 125mhz. the SM802108 accepts a 25 mhz crystal or lvcmos reference clock. data sheets and support documentation can be found on micrel?s web site at: www.micrel.com . features ? generates two lvpecl cl ock outputs at 156.25mhz and two lvpecl clock outputs at 125mhz ? 2.5v or 3.3v operating range ? typical phase jitter @ 156.25mhz (1.875mhz to 20mhz): 110fs (typical) at 3.3v ? industrial temperature range ? green, rohs, and pfos compliant ? available in 24-pin 4mm 4mm qfn package applications ? 10gigabit ethernet ? gigabit ethernet ___________________________________________________________________________________________________________ block diagram
micrel, inc. SM802108 january 2011 2 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 ordering information part number marking shipping junction temperature range package SM802108umg 802108 tube ?40c to +85c 24-pin qfn SM802108umgr 802108 tape and reel ?40c to +85c 24-pin qfn note: 1. devices are green, rohs, and pfos compliant. pin configuration 24-pin qfn (top view) pin description pin number pin name pin type pin level pin function 16, 17 20, 21 /q0, q0 /q1, q1 o, (dif) lvpecl differential clock outputs from bank 1 156.25mhz 23, 24 3, 4 /q2, q2 /q3, q3 o, (dif) lvpecl differential clock outputs from bank 2 125mhz 1 vddo2 pwr power supply for output bank 2 2 vsso2 pwr power supply ground for output bank 2 5 pll_bypass i, (se) lvcmos pll bypass, selects output source 0 = normal pll operation 1 = output from input reference clock or crystal 45k ? pull-down 6 xtal_sel i, (se) lvcmos selects pll input reference source 0 = ref_in, 1 = xtal, 45k ? pull-up
micrel, inc. SM802108 january 2011 3 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 pin description (continued) pin number pin name pin type pin level pin function 7, 12, 15, 19 test factory test pins , do not connect anything to these pins. 8 vdd pwr core power supply 9 ref_in i, (se) lvcmos reference clock input 10 xin i, (se) 12pf crystal crystal reference input, no load caps needed. see fig. 5. 11 xout o, (se) 12pf crystal crystal reference output, no load caps needed. see fig. 5. 13, 14 vss pwr core power supply ground 18 vddo1 pwr power supply for output bank 1 22 vsso1 pwr power supply ground for output bank 1 application information input reference when operating with a crystal input reference, do not apply a switching signal to ref_in. crystal layout keep the layers under the crystal as open as possible. do not place switching signals or noisy supplies under the crystal. truth table pll_bypass xtal_sel input output 0 ? ? pll 1 ? ? xtal/ref_in ? 0 ref_in ? ? 1 xtal ?
micrel, inc. SM802108 january 2011 4 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 absolute maximum ratings (1) supply voltage (v dd , v ddox ) ........................................+4.6v input voltage (v in ). ............................. ?0.50v to v dd + 0.5v lead temperature (solde ring, 20sec .)....................... 260c case temper ature ..................................................... 115c storage temperature (t s ) .........................?65c to +150c operating ratings (2) supply voltage (v dd , v ddox ) ................. +2.375v to +3.465v ambient temperature (t a ) .......................... ?40c to +85c junction thermal resistance (3) qfn ( ja ) still-air .........................................................50c/w qfn ( jb ) juncti on-to-board .......................................30c/w dc electrical characteristics (4) v dd = v ddo1/2 = 3.3v 5% or 2.5v 5% v dd = 3.3v 5%, v ddo1/2 = 3.3v 5% or 2.5v 5% t a = ? 40 c to + 85 c. symbol parameter condition min. typ. max. units v dd , v ddox 2.5v operating voltage 2.375 2.5 2.625 v v dd , v ddox 3.3v operating voltage 3.135 3.3 3.465 v i dd supply current v dd + v ddo outputs open; ref_in source, xtal_sel = 0 130 165 ma i dd supply current v dd + v ddo outputs open; crystal source, xtal_sel = 1 145 185 ma lvpecl dc electrical characteristics (4) v dd = v ddo1/2 = 3.3v 5% or 2.5v 5% v dd = 3.3v 5%, v ddo1/2 = 3.3v 5% or 2.5v 5% t a = ? 40 c to + 85 c. r l = 50 ? to v ddo ? 2v symbol parameter condition min. typ. max. units v oh output high voltage v ddo ? 1.145 v ddo ? 0.97 v ddo ? 0.845 v v ol output low voltage v ddo ? 1.945 v ddo ? 1.77 v ddo ? 1.645 v v swing output voltage swing 0.6 0.8 1.0 v note: 1. permanent device damage may occur if absolute maximum ratings are exceeded. this is a stress rating only and functional oper ation is not implied at conditions other than those detailed in the operational sections of this data shee t. exposure to absolute maximum rating con ditions for extended periods may affect device reliability. 2. the data sheet limits are not guaranteed if t he device is operated beyond the operating ratings. 3. package thermal resistance assumes exposed pad is soldered (o r equivalent) to the devices most negative potential on the pcb . 4. the circuit is designed to meet the ac and dc specifications shown in the above table(s) after thermal equilibrium has been established.
micrel, inc. SM802108 january 2011 5 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 lvcmos (pll_bypass, xtal_sel ) dc electrical characteristics (4) v dd = 3.3v 5%, or 2.5v 5%, t a = ? 40 c to + 85 c. symbol parameter condition min. typ. max. units v ih input high voltage 2 v dd + 0.3 v v in input low voltage ? 0.3 0.8 v i ih input high current v dd = v in = 3.465v 150 a i il input low current v dd = 3.465v, v in = 0v ? 5 a ref_in dc electrical characteristics (4) v dd = 3.3v 5%, or 2.5v 5%, t a = ? 40 c to + 85 c. symbol parameter condition min. typ. max. units v ih input high voltage 1.1 v dd + 0.3 v v il input low voltage ? 0.3 0.6 v i in input current xtal_sel = v il , v in = 0v to v dd ? 5 5 a i in input current xtal_sel = v ih , v in = v dd 20 a crystal characteristics ndk nx2520sa parameter condition min. typ. max. units mode of oscillation 12pf load f undamental, parallel resonant frequency 25 mhz equivalent series resistance (esr) 50 ? shunt capacitor, c0 3 7 pf correlation drive level 100 300 uw
micrel, inc. SM802108 january 2011 6 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 ac electrical characteristics (4, 5) v dd = v ddo1/2 = 3.3v 5% or 2.5v 5% v dd = 3.3v 5%, v ddo1/2 = 3.3v 5% or 2.5v 5% t a = ? 40 c to + 85 c. r l = 50 ? to v ddo ? 2v symbol parameter condition min. typ. max. units f out1 output frequency 1 156.25 mhz f out2 output frequency 2 125 ppm output ppm variation crystal reference. note 6 ? 50 50 ppm f ref reference input frequency 25 mhz t r /t f lvpecl output rise/fall time 20% ? 80% 80 175 350 ps odc output duty cycle 48 50 52 % t skew output-to-output skew within bank. note 7 45 ps t lock pll lock time 20 ms t jit ( ? ) rms phase jitter (8) 156.25mhz integration range (1.875mhz ? 20mhz) integration range (12khz ? 20mhz) 125mhz integration range (1.875mhz ? 20mhz) integration range (12khz ? 20mhz) 110 250 110 250 fs spurious noise components 6.25mhz 25mhz -73 -58 dbc notes: 5. all phase noise measurements were taken with an agilent 5052b phase noise system. 6. crystal tolerance at room less than +/- 15ppm, over temp less than +/- 20ppm. 7. defined as skew between outputs at the same supply voltage and with equal load conditions and same frequency; measured at th e output differential crossing points. 8. measured using 25mhz crystal as the input reference source.
micrel, inc. SM802108 january 2011 7 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 phase noise plots phase noise plot: 156.25mhz, 1.875mhz ? 20mhz 108fs phase noise plot: 156.25mhz, 12khz ? 20mhz 253fs
micrel, inc. SM802108 january 2011 8 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 phase noise plots (continued) phase noise plot: 125mhz, 1.875mhz ? 20mhz 111fs phase noise plot: 125mhz, 12khz ? 20mhz 257fs
micrel, inc. SM802108 january 2011 9 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 figure 1. duty cycle timing figure 2. all outputs rise/fall time figure 3. rms phase/noise/jitter
micrel, inc. SM802108 january 2011 10 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 figure 4. lvpecl output load and test circuit figure 5. crystal input interface
micrel, inc. SM802108 january 2011 11 m9999-012111-a hbwhelp@micrel.com or (408) 955-1690 package information 24-pin qfn 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 micrel makes no representations or warranties with respect to t he accuracy or completeness of the information furnished in this data sheet. this information is not intended as a warranty and micrel does not assume responsibility for it s use. micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. no license, whether expre ss, implied, arising by estoppel or other wise, to any intellectual property rights is granted by this document. except as provided in micrel?s terms and conditions of sale for such products, mi crel assumes no liability whatsoever, and micrel disclaims any express or implied warranty relating to the sale and/or use of micrel products including l iability or warranties relating to fitness for a particular purpose, merchantability, or infringement of an y patent, copyright or other intellectual p roperty right. micrel products are not designed or authori zed for use as components in life support app liances, devices or systems where malfu nction of a product can reasonably be expected to result in pers onal injury. life support devices or system s are devices or systems that (a) are in tended 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 significan t injury to the user. a purchaser?s use or sale of micrel produc ts for use in life support app liances, 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. ? 2011 micrel, incorporated.

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