PCS3P2537a peak emi reduction ic ?2010 scillc. all rights reserved. pu b lication order number: november 2010 C rev. 1.1 p cs3p2537/d feat ures 1x peak emi reduction ic i nput frequency: 18mhz-36mhz output frequency: 18mhz-36mhz frequency deviation @ 27mhz: -0.25% modulation rate @ 27mhz: 30.1khz supply voltage: 3.3v 0.3v operating current less than 8ma @ 27mhz spread spectrum enable control cmos design 8l-wdfn (8l-tdfn) package product description PCS3P2537a is a 1x spread spectrum frequency mo d ulator designed to reduce electromagnetic interference (emi) at the clock source, allowing system wide reduction of emi of down stream clock and data dependent signals. the device allows significant system cost savings by reducing the number of circuit board layers, ferrite beads and shielding and other passive components that are traditionally required to pass emi regulations. PCS3P2537a 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 result in significantly lower system emi compared to the typical narrow band signal produced by oscillators and most frequency generators. lowering emi by increasing a signals bandwidth is called spread spectrum clock generation. PCS3P2537a has a frequency range of 18mhz-36mhz, and accepts input clock either from a crystal or from an external reference and locks on to it delivering a 1x spread spectrum clock output. it has an sson control for enabling and disabling spread spectrum function. PCS3P2537a operates with a supply voltage of 3.3v, and is available in 8 l-wdfn package. application PCS3P2537a is targeted towards pc peripheral devices and embedded systems. bloc k diagram vdd gnd modout sson pll clkin / xin crystal oscillator xout
PCS3P2537a rev. 1 | page 2 of 7 | www.onsemi.com vdd sson clkin / xin 1 2 3 4 5 6 7 8 gnd nc nc modout PCS3P2537a xout pin configuration (8l-wdfn package) pin description pin# pin name type description 1 clkin / xin i external reference clock input or crystal connection. this pin has dual functions. it can be connected either to 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 sson i when sson is high, the spread spectrum is enabled and when low, it turns off the spread spectrum. 4 nc no connect. 5 gnd p ground connection. 6 modout o spread spectrum clock output. 7 nc no connect. 8 vdd p power supply for the entire chip.
PCS3P2537a rev. 1 | page 3 of 7 | www.onsemi.com absolute maximum ratings symbol parameter rating unit vdd, v in voltage on any pin with respect to ground -0.5 to +4.6 v t stg storage temperature -65 to +125 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. exposure to absolute maximum ratings for prolonged periods of time may affect device reliability. operating conditions parameter description min max unit vdd supply voltage 3.0 3.6 v t a operating temperature (ambient temperature) 0 70 c c l load capacitance 15 pf c in input capacitance 7 pf dc electrical characteristics for 3.3v supply symbol parameter min typ max unit v il input low voltage vss-0.3 0.8 v v ih input high voltage 2.0 vdd+0.3 v i il input low current -35 a i ih input high current 35 a v ol output low voltage (vdd = 3.3v, i ol = 8ma) 0.4 v v oh output high voltage (vdd = 3.3v, i oh = 8ma) 2.5 v i dd static supply current 1 2.5 ma i cc dynamic supply current (3.3v, 27mhz and no load) 5 8 ma vdd operating voltage 3 3.3 3.6 v t on power-up time (first locked cycle after power-up) 5 ms z out output impedance 36 note: 1. clkin is pulled to gnd.
PCS3P2537a rev. 1 | page 4 of 7 | www.onsemi.com ac electrical characteristics for 3.3v supply symbol parameter min typ max unit clkin input frequency 18 27 36 mhz modout output frequency 18 27 36 mhz f d frequency deviation @ 27mhz -0.2 -0.25 -0.3 % mr modulation rate @ 27mhz 30 33 khz t lh 1 output rise time (measured from 20% to 80%) 2 ns t hl 1 output fall time (measured at 80% to 20%) 1.5 ns t jc cycle-to-cycle jitter at 27mhz 200 300 ps t d output duty cycle 45 50 55 % note: 1. t lh and t hl are measured into a capacitive load of 15pf.
PCS3P2537a rev. 1 | page 5 of 7 | www.onsemi.com 1 2 3 4 5 6 7 8 gnd nc nc modout xout clkin / xin vdd sson typical application schematic p cb layout recommendation for optimum device performance, the following guidelines a re recommended. dedicated vdd and gnd planes. the device must be isolated from system power supply noise. a 0.01f decoupling capacitor should be mounted on the component side of the board as close to the vdd pin as possible. no vias should be used between the decoupling capacitor and vdd pin. the pcb trace to vdd pin and the ground via should be kept as short as possible. all the vdd pins should have decoupling capacitors. in an optimum layout all components are on the same side of the board, minimizing vias through other signal layers. a typical layout is shown in the figure note: refer to pin description table for functionality details. vdd v dd clkin / xin 0 0 0.01uf as short as possible vdd gnd clkin sson nc xout modout nc gnd
PCS3P2537a rev. 1 | page 6 of 7 | www.onsemi.com package information 8 l-wdfn package symbol dimensions inches millimeters min max min max a 0.027 0.0315 0.70 0.80 a3 0.008 bsc 0.203 bsc b 0.008 0.012 0.20 0.30 d 0.077 0.080 1.95 2.05 e 0.077 0.080 1.95 2.05 e 0.020 bsc 0.50 bsc l 0.020 0.024 0.50 0.60
PCS3P2537a on semiconductor and are registered trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to make changes without further notice 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 special, 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 performance may vary over time. all operating parameters, including typicals must be validated for each customer application by customer's technical experts. scillc does not convey 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 implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the scillc product could create a situation where personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unauthorized application, buyer shall indemnify and hold scillc and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that scillc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employer. u.s patent pending; timing-safe and active bead are trademarks of pulsecore semiconductor, a wholly owned subsidiary of on semiconductor. this literature is subject to all applicable copyright laws and is not for resale in any manner. publication ordering information 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 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 on semiconductor website: www.onsemi.com order literature: http://www.onsemi.com/orderlit for additional information, please contact your local sales representative o rdering code part number top marking package temperature PCS3P2537ag-08cr am 8l-wdfn (8l-tdfn) - tape & reel, green 0c to +70c a microdot placed at the end of last row of marking or just below the last row toward the center of package indicates pb-free.
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