1 of 8 rev: 080607 as general description the ds32khz is a temperature-compensated crystal oscillator (tcxo) with an output frequency of 32.768khz. this device addresses applications requiring better timekeeping accuracy, and can be used to drive the x1 input of most dallas semic onductor real-time clocks (rtcs), chipsets, and other ics containing rtcs. this device is available in commercial (ds32khz) and industrial (ds32khz-n) temperature versions. applications gps receivers telematics network timing and synchr onization in servers, routers, hubs, and switches automatic power meters features accurate to 4 minutes/year (-40c to +85c) accurate to 1 minute/ year (0c to +40c) battery backup for continuous timekeeping v bat operating voltage: 2.7v to 5.5v with v cc grounded v cc operating voltage: 4.5v to 5.5v operating temperature range: 0c to +70c (commercial) -40c to +85c (industrial) no calibration required low-power consumption surface mountable using bga package ul recognized ordering information part temp range pin- package top mark* ds32khz/dip 0oc to +70oc 14 dip ds32khz ds32khzn/dip -40oc to +85oc 14 dip ds32khz-n ds32khzs 0oc to +70oc 16 so (0.300?) ds32khzs ds32khzs# 0oc to +70oc 16 so (0.300?) ds32khzs ds32khzsn -40oc to +85oc 16 so (0.300?) ds32khzsn ds32khzsn# -40oc to +85oc 16 so (0.300?) ds32khzsn ds32khz/wbga 0oc to +70oc 36 bga ds32khz ds32khzn/wbga -40oc to +85oc 36 bga ds32khz-n # denotes a rohs-compliant device that may include lead that is exempt under the rohs requirements. the lead finish is jesd97 category e3, and is compatible with both lead-bas ed and lead-free soldering processes. * a ?#? anywhere on the top mark denotes a rohs-compliant device. an ?n? denotes an industrial device. pin configurations ds32khz 32.768khz temperature-compensated crystal oscillato r www.maxim-ic.com
ds32khz 2 of 8 absolute maximum ratings voltage range on any pin relative to ground????????????????????????-3.0v to +7.0v operating temperature range (noncondensing) commercial:?????????????????????????????????????..0c to +70c industrial:??????????????????????????????????????-40c to +85c storage temperature range???????????????????????????????.-40c to +85c soldering temperature (bga, so)?????????.see the handling, pc board layout, and assembly section. soldering temperature, leads (dip)????????????????????..+260c for 10 seconds ( note 1 ) stresses beyond those listed under ?absolute maximum ratings? may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those i ndicated in the operational sections of t he specifications is not implied. exposure to the absolute maximum rating c onditions for extended periods may affect device reliability. recommended dc op erating conditions (t a = -40c to +85c) (note 1) parameter symbol conditions min typ max units power-supply voltage v cc (note 2) 4.5 5.0 5.5 v battery voltage v bat (notes 2, 3) 2.7 3.0 3.5, 5.5 v dc electrical characteristics (over the operating range, unless otherwise specified.) (note 1) parameter symbol conditions min typ max units active supply current i cc v bat = 0v or 2.7v v bat 3.5v (notes 3, 4) 150 220 a battery input-leakage current i batlkg v cc min v cc v cc max -50 +50 na high output voltage (v cc ) v oh i oh = -1.0ma (note 2) 2.4 v low output voltage v ol i ol = 2.1ma (note 2) 0.4 v high output voltage (v bat ) v oh i oh = -0.1ma (note 2) 2.4 v battery switch voltage v sw (note 2) v bat v (v cc = 0v, t a = -40c to +85c.) (note 1) parameter symbol conditions min typ max units active battery current i bat v bat = 3.3v (notes 4, 5, 6) 1 4 a battery current during temperature measurement i batcnv v bat = 3.3v (notes 4, 5, 7) 450 a note 1: limits at -40c are guaranteed by design and are not production tested. note 2: all voltages are referenced to ground. note 3: v bat must be no greater than 3.5v when the devic e is used in the dual-supply operating modes. note 4: typical values are at +25c and 5.0v v cc , 3.0 v bat , unless otherwise indicated. note 5: these parameters are measured under no output load conditions. note 6: this current is the active-mode current sourced from the backup supply/battery. note 7: a temperature conversion lasts 122ms (typ) and occurs on power-up and then once every 64 seconds.
ds32khz 3 of 8 ac timing characteristics (over the operating range, unless otherwise specified.) parameter symbol conditions min typ max units output frequency f out 32.768 khz 0c to +40c -2.0 +2.0 frequency stability vs. temperature ? f/f o -40c to +85c or 0c to +70c -7.5 +7.5 ppm duty cycle t w /t 45 50 55 % cycle time t cyc (note 8) 30.518 s high/low time t h /t l (note 8) 15.06 s rise time t r (note 8) 200 ns fall time t f (note 8) 60 ns oscillator startup time t osc (note 8) 1 seconds frequency stability vs. operating voltage ? f/ v v cc = 5.0v or v bat = 3.0v, v cc = 0v (notes 4, 9) +2.5 ppm/ v crystal aging (first year) ? f/f o (notes 4, 10) 1.0 ppm note 8: these parameters are measured using a 15pf load. note 9: error is measured from the nominal supply volt age of whichever supply is powering the device. note 10: after reflow. figure 1. ds32khz output waveform
ds32khz 4 of 8 typical operating characteristics (v cc = 3.3v, t a = +25c, unless otherwise noted.) i bat versus v bat 1.5 2 2.5 3 3.5 4 4.5 2.7 3.2 3.7 4.2 4.7 5.2 v bat (v) supply current (ua ) i cc versus v cc 75 85 95 105 115 125 135 145 4.50 4.75 5.00 5.25 5.50 v cc (v) supply current (ua ) frequency deviation versus supply voltage -1 0 1 2 3 4 5 6 7 2.7 3.2 3.7 4.2 4.7 5.2 supply voltage (v) deviation in ppm v bat v cc i bat vs. v bat vs. output load 0.0 2.5 5.0 7.5 10.0 12.5 15.0 2.7 3.2 3.7 4.2 4.7 5.2 v bat supply current (ua ) 10 p f 22pf 47pf 0pf
ds32khz 5 of 8 pin description pin so bga dip name function 1 c4, c5, d4, d5 12 32khz 32.768khz push-pull output 2 c2, c3, d2, d3 13 v cc primary power supply 3?12, 15, 16 a7, a8, b7, b8, c7, c8, d7, d8 1, 6?11, 14 n.c. no connection (must be grounded) 13 all remaining balls 4 gnd ground 14 a4, a5, b4, b5 5 v bat +3v nominal supply input. used to operate the device when v cc is absent. figure 2. delta time and frequency vs. temperature functional description the ds32khz is a temperature-compensated crystal os cillator (tcxo) that outputs a 32,768hz square wave. while the ds32khz is powered by either supply input, t he device measures the temper ature every 64 seconds and adjusts the output frequency. the devic e requires four pins for operation: v cc , gnd, v bat , and 32khz. (see figure 4 for connection schemes.) power is applied through v cc and gnd, while v bat is used to maintain the 32khz output in the absence of power. once every 64 seconds, the ds32khz measures the temperature and adjusts the output frequency. the output is accurate to 2ppm (1 min/yr) from 0c to +40c and to 7.5ppm (4 min/year) from -40c to 0c and from +40c to +85c. -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 20 -40-30-20-10 0 1020304050607080 temperature (c) delta frequency (ppm) -100 -80 -60 -40 -20 0 delta time (min/year) typical crystal, uncompensated ds32khz accuracy band crystal +20ppm crystal -20ppm
ds32khz 6 of 8 the ds32khz is packaged in a 36-pin ball grid array (bga). it also is available in a 16-pin 0.300? so and a 14-pin encapsulated dip (edip) module. the additional pc board space required to add the ds32kh z as an option for driving a rtc is negligible in many applications (see figure 6 ) therefore, adding the ds32khz to new designs and future board revisions allows the use of the ds32khz where applications require improved timekeeping accuracy. figure 3. block diagram operation the ds32khz module contains a quartz tuning-fork crystal and an ic. when power is first applied, and when the device switches between supplies, the ds32khz measur es the temperature and adjusts the crystal load to compensate the frequency. the power supply must remain at a valid level whenever a temperature measurement is made, including when v cc is first applied. while powered, the ds32k hz measures the temperature once every 64 seconds and adjusts the crystal load. the ds32khz is designed to operate in two modes. in the dual-supply mode, a comparator circuit, powered by v cc , monitors the relationship between the v cc and v bat input levels. when v cc drops below a certain level compared to v bat , the device switches over to v bat ( figure 4a ). this mode uses v cc to conserve the battery connected to v bat while v cc is applied. in the single-supply mode, v cc is grounded and the unit is powered by v bat . current consumption is less than v cc , because the comparator circuit is unpowered ( figure 4b ). figure 4a shows how the ds32khz should be connec ted when using two power supplies. v cc should be between 4.5v and 5.5v, and v bat should be between 2.7v and 3.5v. figure 4b shows how the ds32khz can be used when only a single-supply system is available. v cc should be grounded and v bat should then be held between 2.7v and 5.5v. the v bat pin should be connected directly to a battery. figure 4c shows a single-supply mode where v cc is held at +5v. see the frequency stability vs. operating voltage for information about frequency error vs. supply voltage. temperature measurement v bat 32.768khz v cc power switching circuit gnd p n power control dallas semiconductor ds32khz
ds32khz 7 of 8 figure 4. power-supply connections figure 5 illustrates how a standard 32.768khz crystal and the ds32khz should be connected to address the interchangeable option. using this connection scheme an d the recommended layout provides a solution, which requires no hardware modifications. only one device shou ld be used at a time, and both layouts should be located very close together if the recommended layout is not used. the ds32khz i cc and i bat currents are specified with no output loads. many rtc oscillator circuits use a quartz crystal or resonator. driving the oscillator circuit with the rail-to-rail output of the ds32khz can increase the i cc and i bat currents significantly and increase the current consumption of the rtc as well. figure 6 shows one circuit that can be used to reduce the current consumption of a ds 32khz and an rtc. the values of r1 and c1 may vary depending on the rtc used. however, values of 1.0m and 100pf are recommended as a starting point. r2 is used to shift the input waveform to the proper level. the recommended value for r2 is 33k . figure 5. ds32khz connections figure 6. ds32khz a nd rtc connections ds32khz rtc v cc v bat x1 x2 r2 33k c1 100pf r1 1m v cc v bat ds32khz v cc v bat rtc 32khz out 32.768 hz x1 or xin x2 or xout v cc v bat a pc board can be laid out so that the rtc can use either the ds32khz or a crystal gnd gnd 32.768khz out 4.5v - 5.5v vcc vbat gnd gnd 32.768khz out vcc vbat 2.7v - 3.3v 2.7v - 5.5v gnd gnd 32.768khz out vcc vbat 4.5v - 5.5v abc
ds32khz 8 of 8 maxim/dallas semiconductor cannot assume res ponsibility for use of any circuitry other than circuitry entirely embodied in a ma xim/dallas semiconductor product. no circuit patent licenses are implied. maxi m/dallas semiconductor reserves the right to change the circuitry and specification s without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ? 2007 maxim integrated products the maxim logo is a registered trademark of maxim integrated produ cts, inc. the dallas logo is a registered trademark of dallas semiconductor corporation. related application notes (go to www.maxim-ic.com/rtcapps to find these application notes and more.) application note 58: crystal considerat ions with dallas real-time clocks application note 701: using the ds32khz with dallas rtcs handling, pc board layout, and assembly these packages contain a quartz tuning-fork crystal. pick-and-place equipment may be used, but precautions should be taken to ensure that excessive shocks are av oided. ultrasonic cleaning should be avoided to prevent damage to the crystal. avoid running signal traces under th e package, unless a ground plane is placed between the package and the signal line. all n.c. (no connect) pins must be connected to ground. the bga package may be reflowed as long as the peak temperature does not exceed +225c. peak reflow temperature ( 220c) duration should not exce ed 10 seconds, and the total time above 200c should not exceed 40 seconds (30 seconds nominal). for the so package, re fer to the ipc/jedec j-std-020 specification for reflow profiles. exposure to reflow is limited to 2 times ma ximum. the dip package can be wave-soldered, provided that the internal crystal is not exposed to temperatures above +150c. moisture sensitive packages are shipped from the factor y dry-packed. handling instructions listed on the package label must be followed to prevent damage during reflow . refer to the ipc/jedec j-std-020 standard for moisture- sensitive device (msd) classifications. thermal information package type theta-j a (c/w) theta-j c (c/w) 16-pin so (300 mils) 73 23 36-pin bga 43.9 18.4 package information (for the latest package information, go to www.maxim-ic.com/dallaspackinfo .) package type document no. 14-pin encapsulated dip 56-g0001-002 16-pin so (300 mils) 56-g4009-001 36-pin bga 56-g6023-001
engl ish ? ?? ?? ? ?? ? ? ?? ? what 's new products solutions design appnot es support buy com pany m em bers maxim > products > timekeeping, timer s, and counter s ds32khz 32 .7 68k hz te m peratu re -co mp en sa ted crystal os cilla to r industry's most a ccurate tem perature-compensated crystal oscillator (tcxo) q uickvi ew te ch nical docum en ts ord eri ng in fo more in forma tio n al l ordering i nformat ion no te s: o the r o pti ons an d link s f or pu rch asi ng pa rts are lis ted a t: http: //ww w.m axi m- ic.com /s ale s . 1. didn 't find w ha t yo u nee d? ask ou r a ppl ica tion s eng ine ers. exp ert as sis tan ce in fin din g p arts, usu all y with in o ne bu sin es s da y. 2. pa rt nu mb er suf fix es: t or t&r = ta pe an d reel ; + = ro hs/lea d- fre e; # = r ohs/le ad -e xem p t. more: see fu ll data she et o r pa rt na min g con ve nti ons . 3. * som e packa ges h ave va ria tio ns, lis ted on th e dra w in g. "pk gc od e/variati on" te lls w h ich va riation th e p ro duct u ses . 4. d evices: 1-17 of 17 ds32 khz free sa mple buy pa ck age : t ype pi ns footpr int dra wi ng code/v ar * t e mp rohs/le ad-fre e? m ate rials analysis ds32 khz/ wbga-w bga; 36 pin ;1 16 mm dw g: 56 -g60 23- 00 1a ( pdf) u se pkg co de /va ria tion : v36 -1 * 0c to +70 c r ohs/lead -free : no mate ria ls ana lys is ds32 khz/ wbga bga; 36 pin ;1 16 mm dw g: 56 -g60 23- 00 1a ( pdf) u se pkg co de /va ria tion : v36 -1 * 0c to +70 c r ohs/lead -free : no mate ria ls ana lys is ds32 khz/ wbga/t&r- w bga; 36 pin ;1 16 mm dw g: 56 -g60 23- 00 1a ( pdf) u se pkg co de /va ria tion : v36 -1 * 0c to +70 c r ohs/lead -free : no mate ria ls ana lys is ds32 khz/ wbga/t&r bga; 36 pin ;1 16 mm dw g: 56 -g60 23- 00 1a ( pdf) u se pkg co de /va ria tion : v36 -1 * 0c to +70 c r ohs/lead -free : no mate ria ls ana lys is ds32 khzn/w bga bga; 36 pin ;1 16 mm dw g: 56 -g60 23- 00 1a ( pdf) u se pkg co de /va ria tion : v36 -1 * -4 0c to +8 5c r ohs/lead -free : no mate ria ls ana lys is ds32 khzn/w bga-w bga; 36 pin ;1 16 mm dw g: 56 -g60 23- 00 1a ( pdf) u se pkg co de /va ria tion : v36 -1 * -4 0c to +8 5c r ohs/lead -free : no mate ria ls ana lys is ds32 khzn/w bga/t r- w bga; 36 pin ;1 16 mm dw g: 56 -g60 23- 00 1a ( pdf) u se pkg co de /va ria tion : v36 -1 * -4 0c to +8 5c r ohs/lead -free : no mate ria ls ana lys is ds32 khz/ dip mod;14 p in;2 55 m m dw g: 56 -g00 01- 00 2a ( pdf) u se pkg co de /va ria tion : mdp 14 -2 * 0c to +70 c r ohs/lead -free : no mate ria ls ana lys is ds32 khzn/di p mod;14 p in;2 55 m m dw g: 56 -g00 01- 00 2a ( pdf) u se pkg co de /va ria tion : mdp 14 -2 * -4 0c to +8 5c r ohs/lead -free : no mate ria ls ana lys is ds32 khzs# so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6#h2 * 0c to +70 c r ohs/lead -free : r ohs q ua lifie d mate ria ls ana lys is ds32 khzs#t &r so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6#h2 * 0c to +70 c r ohs/lead -free : r ohs q ua lifie d mate ria ls ana lys is ds32 khzsn# so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6#h2 * -4 0c to +8 5c r ohs/lead -free : r ohs q ua lifie d mate ria ls ana lys is ds32 khzsn#t&r so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6#h2 * -4 0c to +8 5c r ohs/lead -free : r ohs q ua lifie d mate ria ls ana lys is ds32 khzs/t&r so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6-h2 * 0c to +70 c r ohs/lead -free : no mate ria ls ana lys is
ds32 khzs so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6-h2 * 0c to +70 c r ohs/lead -free : no mate ria ls ana lys is ds32 khzsn so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6-h2 * -4 0c to +8 5c r ohs/lead -free : no mate ria ls ana lys is ds32 khzsn/t &r so ic ;1 6 p in; 80 mm dw g: 56 -g40 09- 00 1b ( pdf) u se pkg co de /va ria tion : w 1 6-h2 * -2 0c to +8 5c r ohs/lead -free : no mate ria ls ana lys is d idn't find what y ou need? ne xt da y p ro duct sele ctio n ass istance f rom app lica tio ns en gin eers pa ra me tric se arch ap pl ication s hel p quickview t echnical d ocuments ordering i nfo more information d escr iption key featur es a pplications/uses key specifications d iagr am d ata sheet a pplication n otes d esign g uides engineer ing jour nals reliability repor ts s oftwar e/models evaluation kits pr ice and a vailability sam ples buy online package infor m ation l ead-fr ee infor mation related products n otes and comm ents evaluation kits 2 00 7 -0 8 -16 this page last m odified: 20 0 7-0 8 -1 6 c ontac t us: send u s an email copyr ight 20 0 7 by maxim integr ated products, d allas sem iconductor ? l egal n otices ? privacy policy
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