document number: 35022 for technical questions contact: frequency@vishay.com www.vishay.com revision: 02-aug-04 1 miniature smd watch crystal xt38p vishay dale features 2.5mm height industry standard footprint long term stability tape and reel, 3000pcs the xt38p is a 2.5mm height plastic molded 32.768khz smd crystal unit. this thermoplastic molded rugged part is perfect for your smd applications in limited circuit space using the watch frequency. we offer two different footprints of the part to satisfy various pattern layout requirements dimensions in inches [millimeters] parabolic temperature curve to determine frequency stability, use parabolic curvature (k). for example: what is stability at 45?? 1) change in temperature (?) = 45 - 25 = 20? 2) change in frequency = - 0.042ppm*( d ?) = - 0.042ppm*(20) 2 = - 16.8ppm(max) standard electrical specifications parameter symbol condition unit min typical max frequency range f o khz 32.768 frequency tolerance d f/f o at 25? ppm - 20 + 20 frequency coef?ient k parabolic coef?ient ppm/? 2 - 0.027 - 0.035 - 0.043 operating temperature range t opr ? - 40 + 85 storing temperature range t stg ? - 55 + 125 shunt capacitance c o pf 1.0 motional capacitance c 1 ff 2.0 load capacitance cl pf 12.5 insulation resistance ir m w 500 drive level dl w 1.0 aging (?st year) fa at 25? ?3? ppm ?3.0 equivalent series resistance(esr) rs k w 50 ordering information xt38p model a pad layout a or b 32.768khz frequency/khz #1 #2 #4 #3 0.45 0.08 [1.15 0.2] 0.146 [3.7] max. 0.020 0.04 [0.5 0.1] 0.343 [8.7] max. 0.45 0.08 [1.15 0.2] 0.098 [2.5] max. 0.217 0.04 [5.5 0.1] #1 #2 #4 #3 0.45 0.08 [1.15 0.2] 0.146 [3.7] max. xt38pb xt38pa - 20 - 10 0 10 20 30 40 50 60 70 - 10 - 20 - 30 - 40 - 50 - 60 d f/f(ppm) temperature ( c)
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