? semiconductor components industries, llc, 2010 october, 2010 -- rev. 4 1 publication order number: nb2579a/d nb2579a low power, reduced emi clock synthesizer the nb2579a is a versatile spread spectrum frequency modulator designed specifically for a wide range of clock frequencies. the nb2579a reduces electromagnetic interference (emi) at the clock source, allowing system wide reduction of emi of all clock dependent signals. the nb2579a allows significant system cost savings by reducing the number of circuit board layers, ferrite beads and shielding that are traditionally required to pass emi regulations. the nb2579a uses the most efficient and optimized modulation profile approved by the fcc and is implemented by using a proprietary all digital method. the nb2579a 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 increasing a signal?s bandwidth is called ?spread spectrum clock generation?. the nb2579a is targeted towards all portable devices with very low power requirements like mp3 players and digital still cameras. features ? generates an emi optimized clocking signal at the output ? integrated loop filter components ? operates with a 3.3 v / 2.5 v supply ? operating current less than 4.0 ma ? low power cmos design ? input frequency range: 13 mhz to 30 mhz ? generates a 1x low emi spread spectrum clock of the input frequency ? spread spectrum enable control ? frequency deviation ? 1% @ 24 mhz ? available in tsop--6 package (tsot--23--6) ? pb--free package is available marking diagram* *for additional marking information, refer to application note and8002/d. tsop--6 (tsot--23--6) sn suffix case 318g see detailed ordering and shipping information in the package dimensions section on page 7 of this data sheet. ordering information http://onsemi.com e01ayw g g 1 e01 = specific device code a = assembly location y = year w = work week g = pb--free package (note: microdot may be in either location) 1
nb2579a http://onsemi.com 2 figure 1. block diagram modout crystal oscillator frequency divider feedback divider phase detector loop filter xin/clkin xout modulation v dd v co output divider pll v ss sson table 1. key specifications description specification supply voltages v dd =3.3v/2.5v frequency range 13 mhz < clkin < 30 mhz cycle--to--cycle jitter 200 ps (maximum) output duty cycle 45/55% (worst case) modulation rate equation f in /640 frequency deviation ? 1% @ 24 mhz figure 2. pin configuration v dd 1 2 3 6 5 4 sson xout xin/clkin modout nb2579a v ss table 2. pin description pin # pin name type description 1 sson i when sson is high, the spread spectrum is enabled and when low, it turns off the spread spectrum. connect the pin to ground when the s pread spectrum feature is not required. 2 xout o crystal connection. if using an external refe rence, this pin must be left unconnected. 3 xin/clkin i crystal connection or external reference fr equency input. this pin has dual functions. it can be connected either to an external crystal or an external reference clock. 4 v dd p power supply for the entire chip. 5 modout o spread spectrum clock output. 6 v ss p ground connection.
nb2579a http://onsemi.com 3 figure 3. modulation profile table 3. maximum ratings symbol description rating unit v dd, v in voltage on any pin with respect to ground 0.5to+7.0 v t stg storage temperature --65 to +125 ? c t a operating temperature 0to70 ? c t s max. soldering temperature (10 sec) 260 ? c t j junction temperature 150 ? c t dv static discharge voltage (as per mil--std--883, method 3015) 2 kv stresses exceeding maximum ratings may dam age the device. maximum ratings are stres s ratings only. functional operation above the recommended operating conditions is not impli ed. extended exposure to stresses above the re commended operating conditions may affect device reliability.
nb2579a http://onsemi.com 4 table 4. dc electrical characteristics for 2.5 v supply (test conditions: all parameters are measured at room temperature 25 ? c) symbol description min typ max unit v il input low voltage gnd -- 0.3 0.8 v v ih input high voltage 2.0 v dd +0.3 v i il input low current -- 3 5 m a i ih input high current 35 m a i xol xout output low current (@ 0.5 v, v dd =2.5v) 3.0 ma i xoh xout output high current (@ 1.8 v, v dd =2.5v) 3.0 ma v ol output low voltage (v dd =2.5v,i ol =8.0ma) 0.6 v v oh output high voltage (v dd =2.5v,i oh =8.0ma) 1.8 v i dd static supply current (note 1) 1.1 ma i cc dynamic supply current (2.5 v, 24 mhz, and no load) 3.5 ma v dd operating voltage 2.375 2.5 2.625 v t on powerup time (first locked cycle after powerup) (note 2) 5.0 ms z out clock output impedance 50 note: device will meet the specifications after thermal equilibrium has been established when mounted in a test socket or printed circuit board with maintained transverse airflow greater than 500 lfpm . electrical parameters are guaranteed only over the declared operating temperature range. functional operation of the device exceedi ng these conditions is not implied. device specification limit values are applied individually under normal oper ating conditions and not valid simultaneously. 1. xin/clkin pin is pulled low. 2. v dd and xin/clkin input are stable. table 5. ac electrical characteristics for 2.5 v supply symbol description min typ max unit clkin input frequency 13 30 mhz modout output frequency 13 30 mhz f d frequency deviation input frequency = 13 mhz input frequency = 30 mhz ? 1.57 ? 0.8 % t lh (note 3) output rise time (measured at 0.7 v to 1.7 v) 0.7 1.5 1.9 ns t hl (note 3) output fall time (measured at 1.7 v to 0.7 v) 0.4 1.0 1.1 ns t jc jitter (cycle--to--cycle) 200 ps t d output duty cycle 45 50 55 % note: device will meet the specifications after thermal equilibrium has been established when mounted in a test socket or printed circuit board with maintained transverse airflow greater than 500 lfpm . electrical parameters are guaranteed only over the declared operating temperature range. functional operation of the device exceedi ng these conditions is not implied. device specification limit values are applied individually under normal oper ating conditions and not valid simultaneously. 3. t lh and t hl are measured at capacitive load of 15 pf.
nb2579a http://onsemi.com 5 table 6. dc electrical characteristics for 3.3 v supply (test conditions: all parameters are measured at room temperature 25 ? c) symbol description min typ max unit v il input low voltage gnd -- 0.3 0.8 v v ih input high voltage 2.0 v dd +0.3 v i il input low current -- 3 5 m a i ih input high current 35 m a i xol xout output low current (@ 0.4 v, v dd =3.3v) 3.0 ma i xoh xout output high current (@ 2.5 v, v dd =3.3v) 3.0 ma v ol output low voltage (v dd =3.3v,i ol =8.0ma) 0.4 v v oh output high voltage (v dd =3.3v,i oh =8.0ma) 2.5 v i dd static supply current (note 4) 1.2 ma i cc dynamic supply current (3.3 v, 24 mhz, and no load) 4.0 ma v dd operating voltage 2.7 3.3 3.6 v t on powerup time (first locked cycle after powerup) (note 5) 5.0 ms z out clock output impedance 45 note: device will meet the specifications after thermal equilibrium has been established when mounted in a test socket or printed circuit board with maintained transverse airflow greater than 500 lfpm . electrical parameters are guaranteed only over the declared operating temperature range. functional operation of the device exceedi ng these conditions is not implied. device specification limit values are applied individually under normal oper ating conditions and not valid simultaneously. 4. xin/clkin pin is pulled low. 5. v dd and xin/clkin input are stable. table 7. ac electrical characteristics for 3.3 v supply symbol description min typ max unit clkin input frequency 13 30 mhz modout output frequency 13 30 mhz f d frequency deviation input frequency = 13 mhz input frequency = 30 mhz ? 1.57 ? 0.8 % t lh (note 6) output rise time (measured at 0.8 v to 2.0 v) 0.5 1.4 1.7 ns t hl (note 6) output fall time (measured at 2.0 v to 0.8 v) 0.4 1.0 1.2 ns t jc jitter (cycle--to--cycle) 200 ps t d output duty cycle 45 50 55 % note: device will meet the specifications after thermal equilibrium has been established when mounted in a test socket or printed circuit board with maintained transverse airflow greater than 500 lfpm . electrical parameters are guaranteed only over the declared operating temperature range. functional operation of the device exceedi ng these conditions is not implied. device specification limit values are applied individually under normal oper ating conditions and not valid simultaneously. 6. t lh and t hl are measured at capacitive load of 15 pf.
nb2579a http://onsemi.com 6 figure 4. typical cryst al oscillator circuit crystal c1=27pf c2=27pf r1 = 510 xin xout table 8. typical crystal specifications fundamental at cut parallel resonant crystal nominal frequency 14.31818 mhz frequency tolerance ? 50 ppm or better at 25 ? c operating temperature range -- 2 5 ? cto+85 ? c storage temperature -- 4 0 ? cto+85 ? c load capacitance 18 pf shunt capacitance 7 pf maximum esr 25
nb2579a http://onsemi.com 7 ordering information device marking temperature range package shipping ? availability nb2579asnr2 e01 0 ? c--70 ? c tsop--6 (tsot--23--6) 2500 tape & reel now NB2579ASNR2G e01 0 ? c--70 ? c tsop--6 (tsot--23--6) (pb--free) 2500 tape & reel contact sales representative ?for information on tape and reel specificat ions, including part orientation and tape si zes, please refer to our tape and reel packaging specifications brochure, brd8011/d.
nb2579a http://onsemi.com 8 package dimensions tsop--6 case 318g--02 issue u 23 4 5 6 d 1 e b e1 a1 a 0.05 notes: 1. dimensioning and tolerancing per asme y14.5m, 1994. 2. controlling dimension: millimeters. 3. maximum lead thickness includes lead finish. minimum lead thickness is the minimum thickness of base material. 4. dimensions d and e1 do not include mold flash, protrusions, or gate burrs. mold flash, protrusions, or gate burrs shall not exceed 0.15 per side. dimensions d and e1 are determined at datum h. 5. pin one indicator must be located in the indicated zone. c *for additional information on our pb--free strategy and soldering details, please download the on semiconductor soldering and mounting techniques reference manual, solderrm/d. soldering footprint* dim a min nom max millimeters 0.90 1.00 1.10 a1 0.01 0.06 0.10 b 0.25 0.38 0.50 c 0.10 0.18 0.26 d 2.90 3.00 3.10 e 2.50 2.75 3.00 e 0.85 0.95 1.05 l 0.20 0.40 0.60 0.25 bsc l2 -- 0 ? 1 0 ? 1.30 1.50 1.70 e1 e recommended note 5 l c m h l2 seating plane gauge plane detail z detail z 0.60 6x 3.20 0.95 6x 0.95 pitch dimensions: millimeters m on semiconductor and are registered trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to make changes without further noti ce to any products herein. scillc makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation speci al, consequential or incidental damages. ?typical? parameters which may be provided in scillc data sheets and/or specifications can and do vary in different applications and actual performa nce may vary over time. all operating parameters, including ?typicals? must be validated for each custo mer application by customer?s techni cal experts. scillc does not conve y any license under its patent rights nor the rights of others. scillc products are not designed, intended, or authorized for use as components in systems intended for surgical impl ant into the body, or other applications intended to support or sustain life, or fo r any other application in which the failure of the scillc product could create a situation wher e personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unaut horized application, buyer shall indemnify and hold scillc and its offic ers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or in directly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such clai m alleges that scillc was negligent regarding the design or manufactur e of the part. scillc is an equal opportunity/affirmative action employer. this literature is subj ect to all applicable c opyright laws and is not for resale in any manner. publication ordering information n. american technical support : 800--282--9855 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 nb2579a/d literature fulfillment : literature distribution 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 on semiconductor website : www.onsemi.com order literature : http://www.onsemi.com/orderlit for additional information, please contact your loca l sales representative
|
