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Varistor Products High Energy Industrial Square Disc NA Varistor Series The NA Series of transient surge suppressors are varistors (MOVs) in square disc form, intended for special industrial high-energy applications requiring unique electrical contact or packaging methods provided by the customer. The electrode finish of these devices is solderable and can also be used with pressure contacts. Discs may also be stacked. The NA Series varistor is a square 34mm device, with thicknesses ranging from 1.7mm minimum for the 250V device to 7.5mm maximum for the 750V device. For information on mounting considerations refer to Application Note AN8820. This disc is also available with encapsulation and PCB leads. See Littelfuse HB34 Sales. Features * Provided in Disc Form for Unique Packaging by Customer * Solderable Electrode Finish. * Pressure Contacts and/or Disc Stacking may be Utilized * Wide Operating Voltage Range VM(AC)RMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .250V to 750V * Peak Pulse Current Capability (ITM). . . . . . . . . . . . . . . . . . . .40,000A * High Energy Capability (WTM). . . . . . . . . . . . . . . . . . . .370J to 1050J * No Derating Up to 8oC Ambient ALSO SEE HB34 SERIES 122 w w w. l i t t e l f u s e . c o m Varistor Products High Energy Industrial Square Disc NA Varistor Series Absolute Maximum Ratings For ratings of individual members of a series, see Device Ratings and Specifications chart NA SERIES Continuous: Steady State Applied Voltage: AC Voltage Range (VM(AC)RMS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 to 750 DC Voltage Range (VM(DC)) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 to 970 Transient: Peak Pulse Current (ITM) For 8/20s Current Wave (See Figure 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40,000 Single Pulse Energy Range For 2ms Current Square Wave (WTM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370 to1050 Operating Ambient Temperature Range (TA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to 85 Storage Temperature Range (TSTG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to 125 Temperature Coefficient (V) of Clamping Voltage (VC) at Specified Test Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <0.01 UNITS V V 2 VARISTOR PRODUCTS A J C O C %/OC O CAUTION: Stresses above those listed in "Absolute 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 MAXIMUM RATINGS (85 oC) CONTINUOUS TRANSIENT PEAK CURRENT (8/20s) ITM (A) 40,0001 40,0003 40,000 2 40,000 40,000 40,000 40,000 40,000 40,000 40,000 40,000 40,000 VARISTOR VOLTAGE AT 1mA DC TEST CURRENT MIN (V) 184 198 212 354 389 462 610 670 735 805 940 1080 VN(DC) (V) 200 220 240 390 430 510 680 750 820 910 1050 1200 MAX (V) 228 248 268 429 473 561 748 825 910 1000 1160 1320 SPECIFICATIONS (25 oC) MAXIMUM CLAMPING VOLTAGE (VC) AT 200A (8/20s) VC (V) 345 375 405 650 730 830 1,130 1,240 1,350 1,480 1,720 2,000 VRMS SIZE MODEL NUMBER V131NA34 V141NA34 V151NA34 V251NA34 V271NA34 V321NA34 V421NA34 V481NA34 V511NA34 V571NA34 V661NA34 V751NA34 (mm) 34 34 34 34 34 34 34 34 34 34 34 34 VM(AC) (V) 130 140 150 250 275 320 420 480 510 575 660 750 VDC VM(DC) (V) 175 188 200 330 369 420 560 640 675 730 850 970 ENERGY (2ms) WTM (J) 270 291 300 370 400 460 600 650 700 770 900 1050 TYPICAL CAPACITANCE f = 1MHz (pF) 10,000 9,000 8,000 5,000 4,500 3,800 3,000 2,700 2,500 2,200 2,000 1,800 NOTE: Average power dissipation of transients not to exceed 2.0W. 1. Peak current applies to applications rated up to 115VRMS . Peak current is 30kA for applications greater than 115VRMS . 2. Peak current applies to applications rated up to 132VRMS . Peak current is 30kA for applications greater than 132VRMS . 3. Peak current applies to applications rated up to 123VRMS . Peak current is 30kA for applications greater than 123VRMS . w w w. l i t t e l f u s e . c o m 123 Varistor Products High Energy Industrial Square Disc NA Varistor Series Power Dissipation Ratings PERCENT OF RATED VALUE 100 90 80 70 60 50 40 30 20 10 0 -55 50 60 70 80 90 100 110 120 130 140 150 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. The operating values must be derated as shown in Figure 1. AMBIENT TEMPERATURE ( oC) PERCENT OF PEAK VALUE 100 90 FIGURE 1. CURRENT, ENERGY AND POWER DERATING CURVE O1 = Virtual Origin of Wave T = Time From 10% to 90% of Peak T1 = Virtual Front time = 1.25 * t T2 = Virtual Time to Half Value (Impulse Duration) Example: For an 8/20s Current Waveform: 8s = T1 = Virtual Front Time 20s = T2 = Virtual Time to Half Value 50 10 O1 T T1 T2 TIME FIGURE 2. PEAK PULSE CURRENT TEST WAVEFORM Transient V-I Characteristics Curves 10000 MAXIMUM CLAMPING VOL TAGE VARISTOR SIZE 34mm 130 TO 750 VM(AC) RATING TA = -55oC TO 85oC V511NA34 V481NA34 V421NA34 VOLTAGE (V) V751NA34 V661NA34 V571NA34 1000 V321NA34 V131NA34 V151NA34 -5 -4 1E-3 0.01 0.1 1 CURRENT (A) 10 100 1,000 10,000 100,000 V271NA34 V251NA34 100 FIGURE 3. CLAMPING VOLTAGE FOR V131NA34 - V751NA34 124 w w w. l i t t e l f u s e . c o m Varistor Products High Energy Industrial Square Disc NA Varistor Series Pulse Rating Curves 50,000 1 20,000 10,000 SURGE CURRENT (A) 5,000 2,000 1,000 500 200 100 50 20 10 INDEFINITE 20 100 1,000 IMPULSE DURA TION ( s) 10,000 2 10 102 103 104 105 DISC SIZE 34mm V131NA34 - V751NA34 2 106 FIGURE 4. SURGE CURRENT RATING CURVES FOR V131NA34 - V751NA34 NOTE:If pulse ratings are exceeded, a shift of VN(DC) (at specified current) of more than 10% could result. This type of shift, which normally results in a decrease of VN(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 ample protection. Mechanical Dimensions (MILLIMETERS) NA SERIES VARISTOR THICKNESS MILLIMETERS MODEL NUMBER V131NA34 V141NA34 V151NA34 V251NA34 V271NA34 V321NA34 V421NA34 V481NA34 V511NA34 V571NA34 V661NA34 V751NA34 MIN 1.40 1.45 1.50 1.70 1.80 2.10 3.00 3.20 3.60 4.00 4.50 5.20 MAX 2.30 2.55 2.80 2.30 2.70 3.00 4.00 4.40 4.90 5.60 6.80 7.50 INCHES MIN 0.055 0.057 0.059 0.066 0.070 0.082 0.118 0.125 0.141 0.118 0.176 0.204 MAX 0.090 0.100 0.011 0.090 0.106 0.118 0.157 0.173 0.192 0.220 0.267 0.294 NOTE: Parts available encapsulated with soldered tabs, to standard design or customer specific requirements. Also see HB34 Series. w w w. l i t t e l f u s e . c o m 125 VARISTOR PRODUCTS Varistor Products High Energy Industrial Square Disc NA Varistor Series Passivation Layer TEMPERATURE ( oC) 250 The standard NA Series is supplied with passivation layer around the outside perimeter of the disc forming an electrical insulator as detailed in the dimensional drawing. 200 Encapsulated Recommendations After lead attachment, the disc/lead assembly may be coated or encapsulated in a package to provide electrical insulation and isolation from environmental contamination as required by the application. Coating/Filler materials for containers may include silicones, polyurethanes, and some epoxy resins. Two examples of acceptable polyurethanes are Dexter Hysol (US7013, parts A and B) and Rhenatech (resin 4714, hardener 4900), or their equivalents. Materials containing halogens, sulfides, or alkalines are not recommended. 150 100 50 0 0 100 200 300 400 500 600 700 800 900 TIME (SEC) Electrode Metallization The NA Series is supplied with a sintered silver metallization for the electrode finish. The silver metallization is typically used for solder reflow lead attach operations (I-R, Vapour-Phase). The recommended temperature profile of a belt-fed convection oven is shown in Figure 6. FIGURE 6. TYPICAL BEL OVEN TEMPERATURE PROFILE T Stacking and Contact Pressure Recommendations When applications require the stacking of Littelfuse NA discs or when electrical connection is made by pressure contacts, the minimum pressure applied to the disc electrode surface should be 2.2kGs (5 pounds). The maximum recommended pressure applied to the disc electrode is 16N/CM2 (23LBs/IN2). Packaging and Shipping The NA Series is supplied in bulk for shipment. Discs are packaged in compartmentalized cartons to protect from scratching or edge-chipping during shipment. Ordering Information V 25 1 NA 34 VARISTOR DESIGNATOR DISC SIZE (mm) MAX AC RMS WORKING VOLTAGE (FIRST SIGNIFICANT DIGITS) V M(AC) SERIES DESIGNATOR VM(AC) VOLTAGE DECADE MULTIPLIER 126 w w w. l i t t e l f u s e . c o m |
Price & Availability of V751NA34
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