asm3p2108a peak emi reducing solution ?20 10 scillc. all rights reserved. publication order number: january 2010 C rev. 1 asm3p21 08 /d features fcc approved method of emi attenuation. generates a 1x low emi spread spectrum clock of the input frequency. input frequency range: 25mhz to 45mhz. internal loop filter minimizes external components and board space. frequency deviation: - 1.3%( t yp) @ 32mhz. low cycle - to - cycle jitter. 5.0v 5% operating voltage range. ttl or cmos compatible outputs. available in 8 - pin soic and tssop packages. product description the asm3p2108a is a versatile spread spectrum frequency modulator designed specifical ly for input clock frequencies from 25mhz to 45mhz. the asm3p2108a can generate an emi reduced clock from crystal, ceramic resonator, or system clock. the asm3p2108a reduces electromagnetic interference (emi) at the clock source, allowing system wide redu ction of emi of down stream clock and data dependent signals. the asm3p2108a allows significant system cost savings by reducing the number of circuit board layers ferrite beads, shielding and other passive components that are traditionally required to pass emi regulations. the asm3p2108a uses the most efficient and optimized modulation profile approved by the fcc and is implemented in a proprietary all digital method. the asm3p2108a modulates the output of a single pll in order to spread the bandwidth of a synthesized clock, and more importantly, decreases the peak amplitudes of its harmonics. this results in significantly lower system emi compared to the typical narrow band signal produced by oscillators and most frequency generators. lowering emi by inc reasing a signal?s bandwidth is called ?spread spectrum clock generation. ? applications the asm3p2108a is targeted towards emi management for high speed digital applications such as pc peripheral devices, consumer electronics and embedded controller syste ms. block diagram gnd xin xout crystal oscillator frequency divider feedback divider modulation phase detector loop filter vco output divider clockout pll v dd
asm3p2108a rev. 1 | page 2 of 7 | www.onsemi.com clockout 1 2 3 4 5 6 7 8 asm3p2108a xin / clkin xout gnd nc vdd nc nc pin configuration pin description pin# pin name type description 1 xin / clkin i crystal connection or external reference frequency input. this pin has dual functions. it can be connected to either an external crystal or an external reference clock. 2 xout o crystal connection. if using an external reference, this pin must be left unconnected. 3 gnd p ground to entire chip. 4 nc - no connect. 5 clockout o spread spectrum low emi output. 6 vdd p power supply for the entire chip (5v). 7 nc - no connect. 8 nc - no connect.
asm3p2108a rev. 1 | page 3 of 7 | www.onsemi.com absolute maximum ratings symbol parameter rating unit v dd , v in voltage on any pin with respect to ground - 0.5 to +7.0 v t stg storage temperature - 65 to +125 c t a operating temperature 0 to 70 c t s max. soldering temperature (10 sec) 260 c t j junction temperature 150 c t dv static discharge voltage (as per jedec std22 - a114 - b) 2 kv note: these are stress ratings only and are not implied for functional use. exp osure to absolute maximum ratings for prolonged periods of time may affect device reliability. dc electrical characteristics symbol parameter min typ max unit v il input low voltage gnd C 0.3 - 0.8 v v ih input high voltage 2.0 - v dd + 0.3 v i il input low current - 44 - a i ih input high current - 66 - a i xol x out output low current (@ 0.4, v dd = 5v) - 3 - ma i xoh x out output high current (@2.5v, v dd = 5v) - 3 - ma v ol output low voltage (v dd = 5v, i ol = 20ma) - - 0.4 v v oh output high voltage (v dd = 5v, i oh = 20ma) 2.5 - - v i cc dynamic supply current normal mode (5v, 32mhz and 15pf loading) - 40 - ma i dd static supply current standby mode - 40 - a v dd operating voltage 4.75 5.0 5.25 v t on power up time (first locked clock cycle after power up) - 0.18 - ms z out clock out impedance - 50 - ? ac electrical characteristics symbol parameter min typ max unit f in input frequency 25 - 45 mhz modout output frequency 25 - 45 mhz f d frequency deviation input frequency = 25mhz - - 1.98 - % input frequency = 45mhz - - 0.60 - t lh * output rise time (measured at 0.8v to 2.0v) - 440 - ps t hl * output fall time (measured at 2.0v to 0.8v) - 300 - ps t jc jitter (cycle to cycle) - - 360 ps t d output duty cycle 45 50 55 % * v dd = +5v, inpu t frequency = 32mhz, t lh and t hl are measured into a capacitive load of 15pf
asm3p2108a rev. 1 | page 4 of 7 | www.onsemi.com package information 8 - pin soic package symbol dimensions inches millimeters min max min max a1 0.004 0.010 0.10 0.25 a 0.053 0.069 1.35 1.75 a2 0.049 0.059 1. 25 1.50 b 0.012 0.020 0.31 0.51 c 0.007 0.010 0.18 0.25 d 0.193 bsc 4.90 bsc e 0.154 bsc 3.91 bsc e 0.050 bsc 1.27 bsc h 0.236 bsc 6.00 bsc l 0.016 0.050 0.41 1.27 0 8 0 8 d e h d a1 a2 a l c b e
asm3p2108a rev. 1 | page 5 of 7 | www.onsemi.com 8 - pin tssop package symbol dimensions inches millimeters min max min max a 0.043 .. 1.10 a1 0.002 0.006 0.05 0.15 a2 0.033 0.037 0.85 0.95 b 0.008 0.012 0.19 0.30 c 0.004 0.008 0.09 0.20 d 0.114 0.122 2.90 3.10 e 0.169 0.177 4.30 4.50 e 0.026 bsc 0.65 bsc h 0.252 bsc 6.40 bsc l 0.020 0.028 0.50 0.70 0 8 0 8 e h a a1 a2 d b c l e
asm3p2108a rev. 1 | page 6 of 7 | www.onsemi.com ordering codes part number marking package temperature asm3p2108af - 08sr 3p2108af 8 - pin soic, tape and reel, pb free commercial asm3p2108af - 08 - st 3p2108af 8 - pin soic, tube, pb free commercial asm3p2108af - 08 - tr 3p2108af 8 - pin tssop, tape a nd reel, pb free commercial asm3p2108af - 08 - tt 3p2108af 8 - pin tssop, tube, pb free commercial asm3p2108ag - 08 - sr 3p2108ag 8 - pin soic, tape and reel, green commercial asm3p2108ag - 08 - st 3p2108ag 8 - pin soic, tube, green commercial asm3p2108ag - 08 - tr 3p2108ag 8 - pin tssop, tape and reel, green commercial asm3p2108ag - 08 - tt 3p2108ag 8 - pin tssop, tube, green commercial device ordering information a s m 3 p 2 1 0 8 a g - 08 - st licensed under us patent #5,488,627, # 6,646,463 and #5,631,920. o = sot u = msop s = soic e = tqfp t = tssop l = lqfp a = ssop u = msop v = tvsop p = pdip b = bga d = qsop q = qfn x = sc - 70 device pin count x= automotive i= industrial p or n/c = commercial ( - 40c to +125c) ( - 40c to +85c) (0c to +70c) 1 = reserved 6 = power management 2 = non pll based 7 = power management 3 = emi reduction 8 = power management 4 = ddr support products 9 = hi performance 5 = std zero delay buffer 0 = reserv ed on semiconductor mixed signal product part number f = lead free and rohs compliant part g = green package, lead free, and rohs r = tape & reel, t = tube or tray
asm3p2108a note: this product utilizes us patent # 6,646,463 impedance emulator patent issued to pulsecore semiconductor, dated 11 - 11 - 2003 on semiconductor and are registered trademarks of semiconductor components industries, llc (scillc). scillc reserves th e right to make changes without further notice to any products herein. scillc makes no warranty, representation or guarantee regarding the suitabili ty of its products for any particular purpose, nor does scillc assume any liability arising out of the appl ication or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. typical parameters which may be provided in scil n and do vary in different applications and actual performance may vary over time. all operating parameters, including typic als must be publication ordering information literature fulfillment: literature distri bution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone: 303 - 675 - 2175 or 800 - 344 - 3860 toll free usa/canada fax: 303 - 675 - 2176 or 800 - 344 - 3867 toll free usa/canada email: orderlit@onsemi.com n. american technical support : 800 - 282 - 9 855 toll free usa/canada europe, middle east and africa technical support: phone: 421 33 790 2910 japan customer focus center phone: 81 - 3 - 5773 - 3850 on semiconductor website: www.onsemi.com order literature: http://www.onsemi.com/orderlit for additional informa tion, please contact your local sales representative
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