132 www.littelfuse.com varistor products base mount pa varistor series the pa series of transient surge suppressors are metal-oxide varistors (movs) featuring a rigid base mount package construction, and are useful in applications which are subject to vibration. these ul and csa recognized varistors are available in a wide range of operating voltages, from 130v to 660v v m(ac)rms . the base-mount package has a quick-connect tab terminal that provides a fast, secure lead attach. the mounting base forms the second electrical connection, usually chassis ground. meeting rigid nema standards, pa series varistors have a creep and strike distance capability that minimizes breakdown along the package surface. see pa series device ratings and specifications table for part number and brand information. features ?wide operating voltage range v m(ac)rms .................................. .130v to 660v ?creep and strike distance capability meets rigid nema standards ?base mount construction forms one electrical connection ?quick connect tab terminal ?no derating up to 85 o c ambient agency approvals: recognized under the components program of underwriters laboratories. certified by csa. agency file numbers: ul e75961, csa lr91788.
133 www.littelfuse.com varistor products 2 varistor products base mount pa varistor series absolute maximum ratings for ratings of individual members of a series, see device ratings and specifications chart continuous: steady state applied voltage: ac voltage range (v m(ac)rms ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 to 660 v dc voltage range (v m(dc) ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 to 850 v transient: peak pulse current (i tm ) for 8/20? current wave (see figure 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6500 a single pulse energy range for 10/1000? current wave (w tm ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 to 250 j operating ambient temperature range (t a ). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to 85 o c storage temperature range (t stg ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to 125 o c temperature coefficient ( v) of clamping voltage (v c ) at specified test current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <0.01 %/ o c caution: stresses above those listed in ?bsolute maximum ratings may cause permanent damage to the device. this is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. device ratings and specifications pa series units part number and device branding maximum ratings (85 o c) specifications (25 o c) continuous transient varistor voltage at 1ma dc test current max clamping volt v c at test current (8/20 s) typical capaci- tance v rms v dc energy (10/1000 s) peak current (8/20 s) v m(ac) v m(dc) w tm i tm min v n(dc) max v c i p f = 1mhz (v) (v) (j) (a) (v) (v) (v) (v) (a) (pf) v130pa20a 130 175 70 6500 184 200 243 360 100 1900 v130pa20c 130 175 70 6500 184 200 220 325 100 1900 v150pa20a 150 200 80 6500 212 240 284 420 100 1600 v150pa20c 150 200 80 6500 212 240 243 360 100 1600 v250pa40a 250 330 130 6500 354 390 453 675 100 1000 v250pa40c 250 330 130 6500 354 390 413 620 100 1000 v275pa40a 275 369 140 6500 389 430 494 740 100 900 v275pa40c 275 369 140 6500 389 430 453 680 100 900 v320pa40a 320 420 160 6500 462 510 565 850 100 750 v320pa40c 320 350 350 420 460 460 160 165 165 6500 6500 6500 462 500 500 510 559 535 540 618 570 800 910 840 100 100 100 750 700 700 v420pa40a 420 560 170 6500 610 680 790 1160 100 600 v420pa40c 420 560 170 6500 610 680 690 1050 100 600 v480pa80a 480 640 180 6500 670 750 860 1280 100 550 v480pa80c 480 640 180 6500 670 750 790 1160 100 550 v510pa80a 510 675 190 6500 735 820 963 1410 100 500 v510pa80c 510 675 190 6500 735 820 860 1280 100 500 v575pa80a 575 730 220 6500 805 910 1050 1560 100 450 v575pa80c 575 730 220 6500 805 910 960 1410 100 450 v660pa100a 660 850 250 6500 940 1050 1210 1820 100 400 v350pa40a v350pa40c
134 www.littelfuse.com varistor products pa varistor series power dissipation ratings should transients occur in rapid succession, the average power dissipation required is simply the energy (watt-seconds) per pulse times the number of pulses per second. the power so developed must be within the specifications shown on the device ratings and specifications table for the specific device. furthermore, the operating values need to be derated at high temperatures as shown in figure 1. because varistors can only dissipate a relatively small amount of average power they are, therefore, not suitable for repetitive applications that involve substantial amounts of average power dissipation. transient v-i characteristics curves figure 1. current, energy and power derating curve 100 90 80 70 60 50 40 30 20 10 0 -55 50 60 70 80 90 100 110 120 130 140 150 percent of rated value ambient temperature ( o c) figure 2. peak pulse current test waveform 100 90 50 10 o 1 t t 1 t 2 time percent of peak value o 1 = virtual origin of wave t = time from 10% to 90% of peak t 1 = virtual front time = 1.25 ?t t 2 = virtual time to half value (impulse duration) example: for an 8/20 s current waveform: 8 s = t 1 = virtual front time 20 s = t 2 = virtual time to half value figure 3. clamping voltage for v130pa20a - v660pa100a 200 6,000 5,000 4,000 3,000 1,000 900 800 700 600 500 400 300 10 -3 10 -2 10 -1 10 0 10 1 10 2 10 4 maximum peak volts (v) peak amperes (a) 2,000 10 3 maximum clamping voltage ? suffix 130 to 660v m(ac) rating t a = -55 o c to 85 o c v320pa40a a40a v660pa80a v575pa80a v510pa80a v480pa80a v420pa80a v275pa40a v250pa40a v150pa20a v130pa20a figure 4. clamping voltage for v130pa20c - v660pa100c 200 6,000 5,000 4,000 3,000 1,000 900 800 700 600 500 400 300 10 -3 10 -2 10 -1 10 0 10 1 10 2 10 4 maximum peak volts (v) peak amperes (a) 2,000 10 3 maximum clamping voltage ? suffix 130 to 660v m(ac) rating t a = -55 o c to 85 o c v150pa20c v130pa20c v660pa100c v575pa80c v510pa80c v480pa80c v420pa80c v275pa40c v250pa40c v320pa40c v350pa40c base mount
135 www.littelfuse.com varistor products 2 varistor products base mount pa varistor series pulse rating curves mechanical dimensions figure 5. surge current rating curves for v130pa20a - v320pa40c figure 6. surge current rating curves for v420pa40a - v660pa100c 10,000 2,000 200 100 50 20 10 5 2 500 20 100 1,000 10,000 impulse duration ( s) surge current (a) 1 2 10 4 10 5 10 6 disc size 20mm v130pa20a - v320pa40c 10 3 indefinite 1,000 10 2 10 5,000 1 10,000 2,000 200 100 50 20 10 5 2 500 20 100 1,000 10,000 impulse duration ( s) surge current (a) 1 2 10 4 10 5 10 6 disc size 20mm v420pa40a - v660pa100c 10 3 indefinite 1,000 10 2 10 5,000 1 note: if pulse ratings are exceeded, a shift of v n(dc) (at specified current) of more than ?0% could result.this type of shift, which normally results in a decrease of v n(dc) , may result in the device not meeting the original published specifications, but it does not prevent the device from continuing to function, and to provide transient protection notes: 1. tab is designed to fit 1/4 quick-connect terminal. 2. case temperature is measured at t c on top surface of base plate. 3. h 1 (130-150v rms devices). h 2 (250-320v rms devices). h 3 (420-660v rms devices). 4. electrical connection: top terminal and base plate. 5. typical weight: 30g. d q s f c b p 2 holes d 1 t t c h 1, 2, 3 j h e b b 3 t ta b b 2 a seating plane sym- bol millimeters inches notes min nom max min nom max a - - 14.3 - - 0.570 - b - - 6.6 - - 0.260 1 b2 3.94 4.06 4.18 0.155 0.160 0.165 - b3 3.05 3.17 3.29 0.120 0.125 0.130 - b - - 12.9 - - 0.510 - c - - 6.6 - - 0.260 - d - - 66.3 - - 2.610 - d1 - - 33.5 - - 1.320 - e - 11.2 - - 0.440 - - f 7.50 7.62 7.75 0.295 0.300 0.305 - h - 0.8 1.0 - 0.030 0.040 - h 1 - - 25.6 - - 1.010 3 h 2 - - 28.3 - - 1.120 3 h 3 - - 32.8 - - 1.290 3 j - - 8.1 - - 0.320 - p 5.6 - 6.0 0.220 - 0.240 - q 50.6 50.8 51.0 1.990 2.000 2.010 - s 18.4 19.2 20.0 0.72 0.75 0.78 - t - - 1.0 - - 0.040 - t 2.8 - - 0.110 - - - t c - 3.2 - - 0.126 - 2
136 www.littelfuse.com varistor products pa varistor series suggested hardware and mounting arrangements typical non-isolated mounting typical isolated mounting thermal grease layer #10-32 pan head screw #10 flat washer varistor mounting lock washer #10-32 nut surface thermal grease layer #6 flat washer phenolic shoulder spacer varistor mounting lock washer #6-32 nut surface thermal quick connect mica insulator washer #6-32 screw (note 6) note: 6. ge g623, dow corning, dc3, 4, 340, or 640 thermal grease recommended for best heat transfer. 1,000v isolation kit containing the following parts can be ordered by part #a7811055 (qty). ordering information (1) mica insulation 1?3.1?0.005 thick (1) 1/4 quick-connect terminal (2) phenolic shoulder washer (1) spacer (2) #6-32/3 / 4 screw (2) #6-32 nut (2) #6 internal tooth lock washer (2) #6 flat washer varistor v m(ac) 130v to 660v clamping voltage selection designator a = standard c = low clamp voltage option series designator v xxx pa xx x relative energy indicator base mount
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