SIT1572 power, ultra - small 32.768 khz 50 ppm oscillator preliminary features ? 32.768 khz power o scillator ? 10 ppm initial t olerance, 50 ppm over temperature ? smallest footprint: 1.2 mm 2 ? 1.5 x 0.8 mm csp ? no external bypass cap required ? output drives multiple loads and eliminates discrete xtals ? improved stability reduces system power with fewer network timekeeping updates ? ultra - low power: 4.5 a ? supply voltage range: 1.62v to 3.63v ? operating temperature ranges: - 40c to +85c ? pb - free, rohs and reach c ompliant applications ? health and wellness monitors ? wireless connectivity sleep clock ? ulp input devices ? rtc reference clock electrical specifications table 1. electrical characteristics conditions: min/max limits are over temperature, vdd = 1.8v 10%, unless otherwise stated. typicals are at 25c and vdd = 1.8 v. parameter symbol min. typ. max. unit condition frequency and stability output frequency f out 32.768 khz total frequency stability [ 1 ] f_stab - 10 1 10 ppm t a = 25c - 50 50 ppm t a = - 40c to + 85c first year frequency aging f_aging 1 ppm t a = 25c jitter performance period jitter pj 2.5 4 ns rms cycles = 10,000, per jedec standard 65b supply voltage and current consumption operating supply voltage vdd 1.62 1.8 3.63 v no load supply current ldd 4 5.3 a vdd = 1.8v start - up time at power - up t_start 135 300 ms measured when supply reaches 90% of final vdd , to the first output pulse. operating temperature range operating temperature range op_temp - 40 85 c lvcmos output output rise/fall time tr, tf 9 20 ns 10 - 90% (vdd), 15 pf load. output clock duty cycle dc 45 55 % output voltage high voh 90% vdd i oh = - 1 a output voltage low vol 10% vdd i ol = 1 a note: 1. relative to 32.768 khz, includes initial tolerance, over temp stability, 3x reflow, vdd range, board - level underfill, and 20% load variation. tested with agilent 53132a frequency counter. measured with 100 ms gate time for accurate frequency measurement. rev 0.9 january 24, 2018 www.sitime.com
SIT1572 power, ultra - small 32.768 khz 50 ppm oscillator preliminary rev 0.9 page 2 of 7 www.sitime.com table 2. pin description csp pin symbol i/o functionality 1 nc internal test no connect. leave floating. pin 1 is for internal testing and is designed to be left floating. 2 clk out out 32.768 khz, lvcmos compatible output . drive strength is sufficient to drive multiple low - power loads. 3 vdd power supply operates from nominal supply voltages between 1.8v to 3.3v. under normal operating conditions, vdd does not require external bypass/decoupling capacitor(s). SIT1572 includes on - chip filtering capacitors. 4 gnd power supply ground connect to ground. top view figure 1 . pin assignment table 3. absolute maximum limits attempted operation outside the absolute maximum ratings may cause permanent damage to the part. actual performance of the ic is only guaranteed within the operational specifications, not at absolute maximum ratings. parameter test condition value unit continuous power supply voltage range (vdd) - 0.5 to 4.0 v continuous maximum operating temperature range 105 c short duration maximum operating temperature range 30 minutes 125 c human body model (hbm) esd protection jesd22 - a114 2000 v charge - device model (cdm) esd protection jesd22 - c101 750 v machine model (mm) esd protection jesd22 - a115 300 v latch - up tolerance jesd78 compliant mechanical shock resistance mil 883, method 2002 20,000 g mechanical vibration resistance mil 883, method 2007 70 g 1508 csp junction temperature 150 c storage temperature - 65 to 150 c system block diagram figure 2 . SIT1572 block diagram nvm driver vdd clk out nc gnd g n d v d d 1 4 2 3 n c c l k o u t
SIT1572 power, ultra - small 32.768 khz 50 ppm oscillator preliminary rev 0.9 page 3 of 7 www.sitime.com description the SIT1572 is an ultra - small, micropower, 32.768 khz oscillator in a csp - 4 package. typical supply current is 4.5 a under no load condition. sitime 's mems oscillator consists of a mems resonator and a programmable analog circuit. SIT1572 m ems resonator is built with sitimes unique mems first? process. a key manufacturing step is episeal? during which the mems resonator is annealed with temperatures over 1000c. episeal ? creates an extremely strong, clean, vacuum chamber that encapsulates t he mems resonator and ensures the best performance and reliability. during episeal ? , a poly silicon cap is grown on top of the resonator cavity, which eliminates the need for additional cap wafers or other exotic packaging. as a result, sitimes mems reson ator die can be used like any other semiconductor die. one unique result of sitimes mems first and episeal ? manufacturing processes is the capability to integ rate sitimes mems die with a so c, asic, microprocessor or analog die within a package to elimina te external timing components and provide a hig hly integrated, smaller, cost - effective solution to the customer. frequency stability the SIT1572 oscillator is factory trimmed to 32.768 khz at room temperature and internally compensated over temperature . the result is a very accurate oscillator at room temperature and over temperature . unlike quartz crystals that have a classic tuning fork parabola temperature curve with a 25c turnover point with a 0 . 04 to 0.06 ppm/c 2 temperature coefficient, the sit157 2 error is corrected over temperature with an active temperature correction ci rcuit. t he result is < 50 ppm fre quency variation over the - 40 c to +85c temperature range. when measuring the output frequency of SIT1572 with a frequency counter, it is import ant to make sure the counter's gate time is >100 ms. shorter gate times may lead to inaccurate measurements.
SIT1572 power, ultra - small 32.768 khz 50 ppm oscillator preliminary rev 0.9 page 4 of 7 www.sitime.com typical operating curves (t a = 25c, vdd = 1.8v, unless otherwise stated) figure 3 . lvcmos output swing (vdd=1.8v) figure 4 . power supply noise rejection (psnr) n o v d d b y p a s s 1 0 n f v d d b y p a s s
SIT1572 power, ultra - small 32.768 khz 50 ppm oscillator preliminary rev 0.9 page 5 of 7 www.sitime.com d imensions and patterns package size C dimensions (unit: mm) recommended land pattern (unit: mm) recommended 4 - mil (0.1mm) stencil thickness manufacturing guidelines 1) no ultrasonic or megasonic cleaning: do not subject SIT1572 to an ultrasonic or megasonic cleaning environment. permanent damage or long term reliability issues may occur. 2) applying board - level underfill and overmold is acceptable and will not impact the reliability of the device. 3) reflow profile, per jesd22 - a113d. 4) the sit157 2 csp includes a protective, opaque polymer top - coat. if the SIT1572 will see intense light, especially in the 1.0 - 1.2 m ir spectrum, we recommend a protective glob - top epoxy or other cover to keep the light from negatively impacting the frequency stabili ty. 5) for additional manufacturing guidelines and marking/tape - reel instructions, refer to sitime manufacturing notes . # 1 # 2 # 4 # 3 ( s o l d e r m a s k o p e n i n g s s h o w n w i t h d a s h e d l i n e a r o u n d n s m d p a d )
SIT1572 power, ultra - small 32.768 khz 50 ppm oscillator preliminary rev 0.9 page 6 of 7 www.sitime.com ordering information s i t 1 5 7 2 a i - j 3 - 3 3 e - d c c - 3 2 . 7 6 8 q p a r t f a m i l y s i t 1 5 7 2 r e v i s i o n l e t t e r a : i s t h e r e v i s i o n t e m p e r a t u r e r a n g e i : l n d u s t r i a l , - 4 0 t o 8 5 o c p a c k a g i n g s a m p l e s i n c u t t a p e p a c k a g e s i z e s : 8 m m t a p e & r e e l , 1 0 k u r e e l j : 1 . 5 m m x 0 . 8 m m c s p q : 8 m m t a p e & r e e l , 5 k u r e e l e : 8 m m t a p e & r e e l , 1 k u r e e l o u t p u t f r e q u e n c y 3 2 . 7 6 8 f r e q u e n c y s t a b i l i t y 3 : 5 0 p p m l v c m o s o u t p u t s u p p l y v o l t a g e ( v d d ) 1 8 e : 1 . 8 v 1 0 % 2 5 e : 2 . 5 v 1 0 % 3 0 e : 3 . 0 v 1 0 % 3 3 e : 3 . 3 v 1 0 % f o r a p p l i c a t i o n s t h a t r e q u i r e o p e r a t i o n o v e r w i d e r a n g e , e n t e r t h e o p t i o n t h a t c o r r e s p o n d s t o t h e h i g h e s t s u p p l y v o l t a g e .
SIT1572 power, ultra - small 32.768 khz 50 ppm oscillator preliminary rev 0.9 page 7 of 7 www.sitime.com table 4 . revision history version release date change summary 0.9 01/24/2018 preliminary release sitime corporation , 5451 patrick henry drive , santa clara , ca 95054 , usa | phone: + 1 - 408 - 328 - 4400 | fax: +1 - 408 - 328 - 4439 ? sitime corporation 2018. the information contained herein is subject to change at any time without notice. sitime assumes n o responsibility or liability for any loss, damage or defect of a product which is caused in whole or in part by (i) use of any circuitry other than circuitry embodied in a sitime produc t, (ii) misuse or abuse including static discharge, neglect or accident, (iii) unauthorized modification or repairs which have been soldered or alte red during assembly and are not capable of being tested by sitime under its normal test conditions, or (iv) improper installation, storage, handling, warehousing or transportation, or (v) being subjected to unusual physical, thermal, or e lectrical stress. disclaimer: sitime makes no warranty of any kind, express or implied, with regard to this material, and specifically disclaims any and al l express or implied warranties, either in fact or by operation of law, statutory or otherwise, including the implied warranties of merchantability and fitness for use or a particular purpose, and any implied warranty arising from course of dealing or usage of trade, as well as any common - law duties relating to accuracy or lack of negligence, with respect to this material, any sitime product and any product documentation. products sold by sitime are not suitable or intended to be used in a life support application or component, to operate nuclear facilities, or in other mission critical applications where human life may be involved or at stake. all sales are made conditioned upon compliance with the critical uses policy set forth below. critical use exclusion policy buyer agrees not to use sitime's products for any application or in any components used in life support devices or to operate nuclear facilities or for use in other mission - critical applications or components where human life or property may be at stake. sitime owns all rights, title and interest to the intellectual property related to sitime's products, including any software, firmware, copyright, patent, or trademark. the sale of sitime products does not convey or imply any license under patent or other rights. sitime retains the copyright and trademark rights in all documents, catalogs and plans supplied pursuant to or ancillary to the sale of products or services by sitime. unless otherwise agreed to in writing by sitime, any reproduction, modification, translation, compilation, or representation of this material shall be strictly prohibited.
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