SM8721AB seiko npc corporation ? 3-pll multi-output clock generator overview the SM8721AB is a clock generator ic with 3 built-in plls. it can simultaneously generate and output 3 clocks with different frequency derived from a single master clock. the generated output clock frequency can be switched using control pins and one clock can be turned on/off (clk2). the master clock can be selected from a low-cost 14.31818mhz or small 28.636363mhz crystal. the device is available in compact 20-pin qfn packages, making it ideal for portable digital still cameras and other applications which require multiple clocks. features 3.0 to 3.6v supply voltage crystal oscillator circuit built-in 14.318182/28.636363mhz master clock (internal pll reference clock) generated clocks 14.318182/17.734450mhz (ref_clk) 71.877274/90.314686/96.016044 /114.54546mhz (clk1) 48.008022/96.016044mhz (clk2) low jitter output 30ps typ. (1-sigma) 180ps typ. (peak-to-peak) output load 15pf 20-pin qfn package (pb free) applications digital still cameras ordering information pinout (top view) package dimensions (unit: mm) weight: 0.037g device package SM8721AB 20-pin qfn 12345 15 14 13 12 11 10 9 8 7 6 16 17 18 19 20 fs1 fs2 fs3 xtal_sel test1 clk2 vss2 vdd2 ref_clk test2 vdd3 vdd3 vss3 xti xto vdd1 vdd1 vss1 clk2on clk1 0.60 0.10 0.22 0.05 4.00 0.10 1 5 6 10 11 15 16 20 4.20 0.20 4.00 0.10 4.20 0.20 0.50 0.05 m 0.05 0.22 1.00max 0.02 ? 0.02 + 0.03
SM8721AB seiko npc corporation ? block diagram pin description number name i/o description 1 vdd3 analog supply voltage 3 2 vdd3 analog supply voltage 3 3 vss3 analog supply ground 3 4 xti i crystal oscillator element connection pin (14.318182/28.636363mhz) 5 xto o crystal oscillator element connection pin 6 test1 i test pin 1. built-in pull-down resistance (leave open circuit or connect to vss) 7 xtal_sel i crystal oscillator element selection pin. built-in pull-up resistance (high = 28.636mhz, low = 14.318mhz) 8 fs3 i clk1, clk2 output select 3. built-in pull-up resistance 9 fs2 i clk1, clk2 output select 2. built-in pull-up resistance 10 fs1 i ref_clk output select 1. built-in pull-up resistance 11 clk1 o clock output (71/90/96/114mhz switchable output) 12 clk2on i clk2 output enable. built-in pull-up resistance (high = enable, low = disable) 13 vss1 digital supply ground 1 14 vdd1 digital supply voltage 1 15 vdd1 digital supply voltage 1 16 clk2 o clock output (48/96mhz switchable output) 17 vss2 digital supply ground 2 18 vdd2 digital supply voltage 2 19 ref_clk o clock output (14.318/17.734mhz switchable output) 20 test2 i test pin 2. built-in pull-down resistance (leave open circuit or connect to vss) clk2on reference divider 1 phase detector 1 charge pump 1 lpf 1 vco 1 control logic clk1 loop divider 1 (pll1) reference divider 2 phase detector 2 charge pump 2 lpf 2 vco 2 loop divider 2 (pll2) reference divider 3 phase detector 3 charge pump 3 lpf 3 vco 3 loop divider 3 (pll3) xtal_sel clk2 ref_clk fs2 fs1 oscillator xto xti fs3 test1 test2
SM8721AB seiko npc corporation ? absolute maximum ratings v dd = (v dd1 , v dd2 , v dd3 ), v ss = (v ss1 , v ss2 , v ss3 ) unless otherwise noted. recommended operating conditions v ss = (v ss1 , v ss2 , v ss3 ) = 0v, unless otherwise noted. parameter symbol rating unit supply voltage range v dd1 , v dd2 , v dd3 ? 0.3 to 6.5 v supply voltage deviation v dd1 ? v dd2 , v dd1 ? v dd3 , v dd2 ? v dd3 ?.1 v input voltage range v in ? 0.3 to v dd + 0.3 v output voltage range v out ? 0.3 to v dd + 0.3 v power dissipation *1 *1. the power dissipation rating is for a surface-mounted device operating at 85 c. p d 215 mw storage temperature range t stg ? 55 to 125 c parameter symbol conditions rating unit min typ max supply voltage *1 *1. the supply voltages are with reference to v ss = 0v. it is recommended that the voltages applied to pins vdd1, vdd2, vdd3 be supplied from a single source. if various voltage sources are used on pins vdd1, vdd2, vdd3, the voltage supplies should be applied simultaneously. if the tim ing of applying voltage supplies varies, the device may be damaged. v dd1 , v dd2 , v dd3 3.0 3.6 v output load capacitance c l all outputs excluding xto 15 pf master clock frequency f xtal1 xtal_sel = low 14.318182 mhz f xtal2 xtal_sel = high 28.636363 mhz operating temperature t opr ? 40 +85 c
SM8721AB seiko npc corporation ? electrical characteristics dc characteristics v dd = (v dd1 , v dd2 , v dd3 ) = 3.3 0.3v, v ss = (v ss1 , v ss2 , v ss3 ) = 0v, ta = ? 40 to +85 c unless otherwise noted. parameter symbol pins conditions rating unit min typ max current consumption i dd vdd v dd = 3.3v, ta = 25 c, all outputs operating without load ?050ma input voltage v ih xtal_sel, fs1, fs2, fs3, clk2on, test1, test2 *1,*2 *1. xtal_sel, fs1, fs2, fs3, clk2on pins have schmitt-trigger inputs with internal pull-up resistance. v dd = 3.3v 0.8v dd v v il 0.2v dd v input current i ih1 xtal_sel, fs1, fs2, fs3, clk2on *1 v in = v dd 1 a i il1 v in = 0v ? 100 ? i ih2 test1, test2 *2 *2. test1, test2 pins have schmitt-trigger inputs with internal pull-down resistance. v in = v dd 100 ? i il2 v in = 0v ? 1 a i ih3 xti v in = v dd 40 ? i il3 v in = 0v ?0 ? output voltage v oh clk1, clk2, ref_clk i oh = ? 2ma v dd ? 0.4 v v ol i ol = 2ma 0.4 v
SM8721AB seiko npc corporation ? ac characteristics v dd = (v dd1 , v dd2 , v dd3 ) = 3.3 0.3v, v ss = (v ss1 , v ss2 , v ss3 ) = 0v, ta = ? 40 to +85 c unless otherwise noted. parameter symbol pins conditions rating unit min typ max output clock rise time *1 *1. measured using the circuit shown in ?ure 1 on the npc standard evaluation board. t r clk1, clk2, ref_clk c l = 15pf, v ol = 0.2v dd to v oh = 0.8v dd transition 2.0 ns output clock fall time *1 t f clk1, clk2, ref_clk c l = 15pf, v oh = 0.8v dd to v ol = 0.2v dd transition 2.0 ns output clock jitter *2,*3 *2. measured using the circuit shown in ?ure 2 on the npc standard evaluation board. *3. the crystal oscillator element coef?ients for characteristics measurements are described below (hp4195 measurement equipmen t). f = 14.318182mhz crystal: r = 12.16 ? , l = 10.34mh, ca = 11.95ff, cb = 4.03pf f = 28.636363mhz crystal: r = 12.50 ? , l = 5.89mh, ca = 5.25ff, cb = 1.65pf t jitter (1-sigma) clk1, clk2, ref_clk ta = 25 c, c l = 15pf, v o = 0.5v dd ?0 ps t jitter (peak-peak) clk1, clk2, ref_clk ta = 25 c, c l = 15pf, v o = 0.5v dd 180 ps output clock duty cycle *1, *3 dt1 clk1, clk2, ref_clk ta = 25 c, c l = 15pf, v o = 0.5v dd 45 50 55 % dt2 clk1 ta = 25 c, c l = 15pf, v o = 0.5v dd , 114.54546mhz 40 50 60 % power-up time *3,*4,*5 *4. the power-up time is the time from when the supply reaches 3.0v after the supply is turned on until each output clock reache s its designated frequency to within ?.1%. *5. measured using the npc standard evaluation board. t p clk1, clk2, ref_clk ?5ms figure 1. measurement circuit 1 figure 2. measurement circuit 2 l ca r cb frequency & time interval analyzer (hp5371a) 14.318182/ 28.636363mhz oscilloscope (infinium hp54845a) passive probe (hp10435a) active probe (hp1152a) dut dut:device under test jitter measurement system (asa, m1) oscilloscope (infinium hp54845a) active probe (hp1152a) dut dut:device under test 14.318182/ 28.636363mhz
SM8721AB seiko npc corporation ? functional description 14.318182/28.636363mhz master clock the 14.318182/28.636363mhz master clock is generated by the crystal oscillator formed by connecting a crystal (14.318182/28.636363mhz fundamental frequency) between pins xti (pin 4) and xto (pin 5), as shown in gure 3. figure 3. crystal oscillator connection oscillator xti (pin 4) xto (pin 5) ref_clk (pin 19) c1 c2 c1, c2 = 0 to 33pf 14.318182/ 28.636363mhz selector 1/2 pll selector
SM8721AB seiko npc corporation ? output clock frequency the SM8721AB generates 3 output clocks with frequency 14.318182/17.734450mhz (ref_clk), 71.877274/90.314686/96.016044/114.54546mhz (clk1), and 48.008022/96.016044mhz (clk2), derived from the master clock. a list of the supported clock frequency and control settings is shown in table 1. table 1. output clock frequency 14.318182mhz master clock frequency: xtal_sel = low 28.636363mhz master clock frequency: xtal_sel = high fs1 (pin 10) fs2 (pin 9) fs3 (pin 8) clk2on (pin 12) output clock frequency [mhz] ref_clk (pin 19) clk1 (pin 11) clk2 (pin 16) high high high high 14.318182 96.016044 48.008022 low 17.734450 high low 14.318182 90.314686 low 17.734450 high high low 14.318182 71.877274 low 17.734450 high low 14.318182 114.54546 96.016044 low 17.734450 high high high low 14.318182 96.016044 fixed low low 17.734450 high low 14.318182 90.314686 low 17.734450 high high low 14.318182 71.877274 low 17.734450 high low 14.318182 114.54546 low 17.734450
SM8721AB seiko npc corporation ? nc0120be 2006.04 please pay your attention to the following points at time of using the products shown in this document. the products shown in this document (hereinafter ?roducts? are not intended to be used for the apparatus that exerts harmful in?ence on human lives due to the defects, failure or malfunction of the products. customers are requested to obtain prior written agreeme nt for such use from seiko npc corporation (hereinafter ?pc?. customers shall be solely responsible for, and indemnify and hold npc free and harmless from, any and all claims, damages, losses, expenses or lawsuits, due to such use without such agreement. npc reserves the right to change the speci?ations of the products in order to improve the characteristic or reliability thereof. npc makes no claim o r warranty that the contents described in this document dose not infringe any intellectual property right or other similar right owned by third parties. therefore, npc shall not be responsible for such problems, even if the use is in accordance with the descriptions provided in t his document. any descriptions including applications, circuits, and the parameters of the products in this document are for reference to use the products, and shall not be guaranteed free from defect, inapplicability to the design for the mass-production products without further te sting or modi?ation. customers are requested not to export or re-export, directly or indirectly, the products to any country or any ent ity not in compliance with or in violation of the national export administration laws, treaties, orders and regulations. customers are req uested appropriately take steps to obtain required permissions or approvals from appropriate government agencies. seiko npc corporation 15-6, nihombashi-kabutocho, chuo-ku, tokyo 103-0026, japan telephone: +81-3-6667-6601 facsimile: +81-3-6667-6611 http://www.npc.co.jp/ email: sales @ npc.co.jp
|
