DS1080CL spread-spectrum crystal multiplier ________________________________________________________________ maxim integrated products 1 19-6068; rev 1; 10/11 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. general description the DS1080CL is a low-jitter, crystal-based clock gen- erator with an integrated phase-locked loop (pll) to generate spread-spectrum clock outputs from 8mhz to 64mhz. the device is pin programmable to select the clock multiplier rate as well as the dither magnitude. the DS1080CL has a spread-spectrum disable mode and a power-down mode to conserve power. applications features ? generates spread-spectrum clocks from 8mhz to 64mhz ? selectable clock multiplier rates of 1x, 2x, and 4x ? center spread-spectrum dithering ? selectable spread-spectrum modulation magnitudes of ?.5%, ?.0%, and ?.5% ? spread-spectrum disable mode ? low cycle-to-cycle jitter ? power-down mode with high-impedance output ? low-power consumption ? 3.0v to 3.6v single-supply operation ? -40? to +125? temperature operation ? small 8-pin sop package sso pdn smsel 1 2 8 7 x2 v cc gnd cmsel x1 top view 3 4 6 5 DS1080CL + pin configuration + denotes a lead-free package. /v denotes an automotive qualified part. t = tape and reel. ordering information part temp range pin-package DS1080CLu+ -40c to +125c 8 sop DS1080CLu+t -40c to +125c 8 sop DS1080CLu/v+ -40c to +125c 8 sop DS1080CLu/v+t -40c to +125c 8 sop automotive cable modems cell phones computer peripherals copiers infotainment pcs printers x2 note: in the above configuration with pdn connected to v cc , smsel connected to gnd, and cmsel open, the device is in normal operation with 2x clock multiplication and a spread-spectrum magnitude of 0.5%. f sso v cc v cc v cc sso pdn x1 crystal c l1 c l2 decoupling capacitor gnd cmsel smsel 8 7 6 5 1 2 3 4 DS1080CL typical operating circuit
DS1080CL spread-spectrum crystal multiplier 2 _______________________________________________________________________________________ absolute maximum ratings recommended operating conditions (t a = -40? to +125?, unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. voltage range on v cc relative to gnd .............-0.5v to +3.63v voltage range on any pin relative to gnd ...............-0.5v to (v cc + 0.5v), not to exceed +3.63v continuous power dissipation (t a = +75?) ?op (derate 4.5mw/? above +70?).......................362mw operating temperature range .........................-40? to +125? storage temperature range .............................-55? to +125? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) .......................................+260? parameter symbol conditions min typ max units supply voltage v cc (note 1) 3.0 3.6 v input logic 1 v ih 0.8 x v cc v cc + 0.3 v input logic 0 v il v gnd - 0.3 0.2 x v cc v input logic open i if 0v < v in < v cc (note 2) 1 a input leakage i il 0v < v in < v cc (note 3) 80 a sso load c sso 15 pf crystal or clock input frequency f in 8 16 mhz crystal esr x esr 90 clock input duty cycle f indc 40 60 % crystal parallel load capacitance c l (note 4) 18 pf dc electrical characteristics (v cc = +3.0v to +3.6v, t a = -40? to +125?, unless otherwise noted.) parameter symbol conditions min typ max units supply current i cc1 c sso = 15pf, f sso = 8mhz 7 12 ma power-down current i ccq pdn = gnd, all input pins open 200 a output leakage (sso) i oz pdn = gnd -1 +1 a low-level output voltage (sso) v ol i ol = 4ma 0.4 v high-level output voltage (sso) v oh i oh = -4ma 2.4 v input capacitance (x1/x2) c in (note 5) 5 pf
DS1080CL spread-spectrum crystal multiplier _______________________________________________________________________________________ 3 ac electrical characteristics (v cc = +3.0 to +3.6v, t a = -40c to +125c, unless otherwise noted.) parameter symbol conditions min typ max units sso duty cycle ssodc measured at v cc /2 45 55 % rise time t r (note 6) 1.6 ns fall time t f (note 6) 1.6 ns peak cycle-to-cycle jitter t j f sso = 8mhz, t a = -40c to +85c, 10,000 cycles (note 5) 75 ps 8mhz 20 power-up time t por pdn pin (note 7) 16mhz 10 ms power-down time t pdn pdn pin (notes 8, 9) 100 ns dither rate f dither f in /512 note 1: all voltages referenced to ground. note 2: maximum source/sink current applied to input to be considered an open. note 3: applicable to pins cmsel, smsel, and pdn . note 4: see information about c l1 and c l2 in the applications information section. note 5: not production tested. note 6: for 15pf load. note 7: time between pdn deasserted to output active. note 8: time between pdn asserted to output high impedance. note 9: guaranteed by design.
DS1080CL spread-spectrum crystal multiplier 4 _______________________________________________________________________________________ typical operating characteristics (v cc = 3.3v, t a = +25c, unless otherwise noted.) supply current vs. supply voltage DS1080CL toc01 supply voltage (v) supply current (ma) 3.55 3.45 3.35 3.25 3.15 3.05 2 4 6 8 10 12 0 2.95 3.65 f in = 8mhz cmsel = 4x cmsel = 2x cmsel = 1x supply current vs. temprature DS1080CL toc02 temperature ( c) supply current (ma) 110 85 60 35 10 -15 2 4 6 8 10 12 14 0 -40 f in = 8mhz cmsel = 4x cmsel = 2x cmsel = 1x supply current vs. frequency DS1080CL toc03 frequency (mhz) supply current (ma) 56 48 40 32 24 16 2 4 6 8 10 12 0 864 v cc = 3.6v v cc = 3.0v duty cycle vs. temperature DS1080CL toc04 temperature ( c) duty cycle (%) 110 60 10 46 47 48 49 50 51 52 53 54 55 45 -40 cmsel = 4x cmsel = 2x f in = 8mhz cmsel = 1x duty cycle vs. supply voltage DS1080CL toc05 supply voltage (v) duty cycle (%) 3.5 3.4 3.3 3.2 3.1 46 47 48 49 50 51 52 53 54 55 45 3.0 3.6 cmsel = 4x cmsel = 2x f in = 8mhz cmsel = 1x frequency spectrum at 64mhz DS1080CL toc06 frequency (mhz) attenuation (db) 66 65 64 63 62 -80 -70 -60 -50 -40 -30 -20 -10 0 -90 61 67 -11db -15.6db -14.1db
DS1080CL spread-spectrum crystal multiplier _______________________________________________________________________________________ 5 crystal oscillator 1x/2x/4x clock multiplying pll with spread spectrum configuration decode and control v cc v cc gnd note: see information about c l1 and c l2 in the applications information section. pdn sso cmsel smsel x1 x2 8mhz to 16mhz f sso = 8mhz to 64mhz c l1 c l2 f in f sso DS1080CL block diagram pin description pin name function 1 x1 crystal drive/clock input. a crystal with the proper loading capacitors is connected across x1 and x2. instead of a crystal, a clock can be applied at the x1 input. 2 gnd signal ground 3 cmsel clock multiplier select. trilevel digital input. 0 = 1x open = 2x 1 = 4x 4 smsel spread-spectrum magnitude select. trilevel digital input. 0 = 0.5% open = 1.0% 1 = 1.5% 5 pdn power-down/spread-spectrum disable. trilevel digital input. 0 = power-down/sso high impedance open = power-up/spread spectrum disabled 1 = power-up/spread spectrum enabled 6 sso spread-spectrum clock multiplier output. outputs a 1x, 2x, or 4x spread-spectrum version of the crystal or clock applied at the x1/x2 pins. 7 v cc supply voltage 8 x2 crystal drive output. a crystal with the proper loading capacitors is connected across x1 and x2. if a clock is connected to x1, then x2 should be left open circuit.
DS1080CL spread-spectrum crystal multiplier 6 _______________________________________________________________________________________ detailed description the DS1080CL is a crystal multiplier with center spread-spectrum capability. an 8mhz to 16mhz crystal is connected to the x1 and x2 pins. alternately, an 8mhz to 16mhz clock can be applied to x1 in place of the crystal. in such applications, x2 would be left open circuit. using the cmsel input, the user selects whether the attached crystal or input clock is multiplied by 1, 2, or 4. the DS1080CL can generate spread- spectrum clocks from 8mhz to 64mhz. the pll can dither the output clock about its center fre- quency at a user-selectable magnitude. using the smsel input, the user selects the dither magnitude. the pdn input can be used to place the device into a low-power standby mode where the sso output is high impedance. if the pdn pin is open, the sso output is active but the spread-spectrum dithering is disabled. the spread-spectrum dither rate is fixed at f in /512 to keep the dither rate above the audio frequency range. on power-up, the output clock (sso) remains high impedance until the pll reaches a stable frequency (f sso ) and dither (f dither ). a power cycle is needed for the pll whenever there is a change in input fre- quency, cmsel, or smsel. +1.5% +1.0% +0.5% -0.5% f o -1.0% -1.5% dither cycle rate = f dither = f in /512 f sso t figure 1. spread-spectrum frequency modulation
DS1080CL spread-spectrum crystal multiplier _______________________________________________________________________________________ 7 applications information crystal selection the DS1080CL requires a parallel resonating crystal operating in the fundamental mode, with an esr of less than 90 . the crystal should be placed very close to the device to minimize excessive loading due to para- sitic capacitances. oscillator input when driving the DS1080CL using an external oscillator clock, consider the input (x1) to be high impedance. crystal capacitor selection the load capacitors c l1 and c l2 are selected based on the crystal specifications (from the data sheet of the crystal used). the crystal parallel load capacitance is calculated as follows: for the DS1080CL use c l1 = c l2 = c lx . in this case, the equation then reduces to: where c l1 = c l2 = c lx. equation 2 is used to calculate the values of c l1 and c l2 based on values of c l and c in noted in the electri- cal specifications. power-supply decoupling to achieve best results, it is highly recommended that a decoupling capacitor is used on the ic power-supply pins. typical values of decoupling capacitors are 0.001f and 0.1f. use a high-quality, ceramic, sur- face-mount capacitor, and mount it as close as possi- ble to the v cc and gnd pins of the ic to minimize lead inductance. layout considerations as noted earlier, the crystal should be placed very close to the device to minimize excessive loading due to parasitic capacitances. care should also be taken to minimize loading on pins that could be open as a pro- gramming option (smsel and cmsel). coupling on inputs due to clocks should be minimized. package information for the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. (2) c c c l lx in =+ 2 (1) c cxc cc c l ll ll in = + + 12 12 package type package code outline no. land pattern no. 8 sop u8+1 21-0036 90-0092
DS1080CL spread-spectrum crystal multiplier maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ? 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 0 5/08 initial release 1 10/11 updated the ordering information table and the absolute maximum ratings section; added the land pattern no. to the package information table 1, 2, 7
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