V26SM20 LITTELFUSE | Alldatasheet

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Technical content

Features

  • DC Voltage Rating 26VDC
  • AC Voltage Rating 175 - 320AC
  • No De-Rating up to 85°C ambient
  • Lead-Free, Halogen- Free and RoHS Compliant
  • Low voltage devices specified for automotive load dump energy
  • Available in "waffle" tray packaging Agency Approvals Absolute Maximum Ratings
  • For ratings of individual members of a series, see Device Ratings and Specifications chart Agency Agency File Number E320116 Continuous SM20 Series Units Steady State Applied Voltage: AC Voltage Range (VM(AC)RMS) 20 to 320 V DC Voltage Range (VM(DC))2 6 V Transients: Peak Pulse Current (ITM) 8/20μs Current Wave, Single Pulse up to 6500 A Single Pulse Energy Capability (WTM) 10/1000μs Current Wave 165 J Load Dump Energy Capability (td>=30ms) 160 J Operating Ambient Temperature Range (TA) -40 to +85 OC Storage Temperature Range (TSTG) -55 to +125 OC Temperature Coefficient (aV) of Clamping Voltage (VC) at Specified Test Current <0.01 %/ OC Hi-Pot Encapsulation (COATING Isolation Voltage Capability) (Dielectric must withstand indicated DC voltage for one minute per MIL -STD 202, Method 301) 2500 V COATING Insulation Resistance 1000 MΩ 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. SM20 Varistor Series

©2010 Littelfuse, Inc. Revision: May 11, 2010 SM20 Series Varistor Surface Mount Varistors > SM20 Series Specifications are subject to change without notice. Please refer to www.littelfuse.com/series/sm20.html for current information. Repetitive Surge Capability V175SM20 - V320SM20 10,000 2,000 200 100 500 20 100 1,000 10,000 IMPULSE DURATION (μs) SURGE CURRENT (A) 1 2 104 105 106 MODEL SIZE 20mm V175SM20 - V320SM20 103 INDEFINITE 1,000 102 105,000 For applications exceeding 85ºC ambient temperature, the peak surge current and energy ratings must be reduced as shown below Peak Pulse Current T est Waveform for Clamping Voltage Peak Current, Energy and Power Derating Curve 01 = Virtual Origin of Wave T = Time from 10% to 90% of Peak T 1 = Rise Time = 1 .25 x T T2 = Decay Time Example - For an 8/20 μs Current Waveform: 8μs = T1 = Rise Time 20μs = T2 = Decay Time PERCENT OF PEAK VALUE Test0 100 TIM E t t 100 -55 50 60 70 80 90 100 110 120 130 140 150 AMBIENT TEMPERATURE ( oC) PERCENT OF RATED VALUE SM20 Series Ratings & Specifications Maximum Rating (85°C) Specifications (2 5°C) Continuous Transient Varistor Voltage at 1mA DC Test Current Maximum Clamping Voltage 8 x 20 μs Typical Capacitance f = 1MHzVRMS VDC Energy 10 x 1000μs Peak Current 8 x 20μs Part Number Branding VM(AC) VM(DC) WTM 1x pulse ITM 1x pulse VNOM Min V NOM Max V C IPK C (V) (V) (J) (A) (V) (V) (V) (A) (pF) V26SM20 26SM20 20 26 20 160 (note 1) 2000 32 (10mA) (10mA) 63 20 12000 V175SM20 175SM20 175 225 90 6500 247 303 455 100 1400 V230SM20 230SM20 230 300 122 6500 324 396 595 100 1100 V250SM20 250SM20 250 330 130 6500 354 429 650 100 1000 V275SM20 275SM20 275 369 140 6500 389 473 710 100 900 V300SM20 300SM20 300 405 165 6500 420 517 775 100 800 V320SM20 320SM20 320 420 150 6500 462 540 810 100 750 1 . Energy rating for impulse duration of 30ms minimum to one half of peak current (automotive load dump).

©2010 Littelfuse, Inc. Revision: May 11, 2010 SM20 Series Varistor Surface Mount Varistors > SM20 Series Specifications are subject to change without notice. Please refer to www.littelfuse.com/series/sm20.html for current information. SM20 Series Lead (Pb) Soldering Recommendations The principal techniques used for the soldering of components in surface mount technology are IR Re-flow and Wave soldering. Typical profiles are shown on the right. The terminals of SM20 series devices are tin plated copper, and the recommended solder is 62/36/2 (Sn/Pb/Ag), 60/40 (Sn/Pb) or 63/37 (Sn/Pb). Littelfuse also recommends an RMA solder flux. Wave soldering is the most strenuous of the processes. To avoid the possibility of generating stresses due to thermal shock, a preheat stage in the soldering process is recommended, and the peak temperature of the solder process should be rigidly controlled. When using a reflow process, care should be taken to ensure that the SM20 chip is not subjected to a thermal gradient steeper than 4 degrees per second; the ideal gradient being 2 degrees per second. During the soldering process, preheating to within 100 degrees of the solder's peak temperature is essential to minimize thermal shock. Once the soldering process has been completed, it is still necessary to ensure that any further thermal shocks are avoided. One possible cause of thermal shock is hot printed circuit boards being removed from the solder process and subjected to cleaning solvents at room temperature. The boards must be allowed to cool gradually to less than 50ºC before cleaning. Lead–free (Pb-free) Soldering Recommendations The terminals of SM20 series devices are tin plated copper, and the recommended Lead-free solder is 96.5/3.0/0.5 (SnAgCu) with an RMA flux, though there is a wide selection of pastes and fluxes available that should be compatible. The reflow profile must be constrained by the maximums in the Lead–free Reflow Profile. For Lead–free Wave soldering, the Wave Solder Profile still applies. Note: the Lead–free paste, flux and profile were used for evaluation purposes by Littelfuse, based upon industry standards and practices. There are multiple choices of all three available, it is advised that the customer explores the optimum combination for their process as processes vary considerably from site to site. PREHEAT ZONE PREHEAT DWELL RAMP RATE <2°C/s MAXIMUM TEMPERATURE 230°C TEMPERATURE °C TIME (MINUTES) 250 200 150 100 40-80 SECONDS ABOVE 183°C TIME (MINUTES) 300 250 200 150 100 MAXIMUM WA VE 260°C SECOND PREHEA T FIRST PREHEAT TEMPERATURE °C MAXIMUM TEMPERATURE 250˚C, TIME WITHIN 5˚C OF PEAK

20 SECONDS MAXIMUM

<3˚C/s 60 - 150 SEC > 217˚C TEMPERATURE °C TIME (MINUTES) 300 250 200 150 100 Reflow Solder Profile Wave Solder Profile Lead–free Re-flow Solder Profile

©2010 Littelfuse, Inc. Revision: May 11, 2010 SM20 Series Varistor Surface Mount Varistors > SM20 Series Specifications are subject to change without notice. Please refer to www.littelfuse.com/series/sm20.html for current information. Part Numbering System For “VARISTOR” Max Voltage Rating (Two or three digits -- refer to ratings and specifications table) V 275 SM20 SM20 SERIES /g27 /g25 /g22/g27 /g54/g20 /g54/g21 /g54/g82/g79/g71/g72/g85/g76/g81/g74/g3/g51/g68/g71/g3/g47/g68/g92/g82/g88/g87 /g43/g20 /g43/g21 /g87 /g58 /g39 Product Dimensions Symbol Millimeters Min Max D (diameter) --- 26 H1 --- 10.5 H2 1. 0 - - t 0.50 0.70 S1 32.5 35 S2 3.0 4.5 W 6.2 6.6 Packaging 192 mm 30 mm typical 192 mm 30 mm typical 8.4 mm typical Radius 30 mm typical 11.7 mm pocket depth Standard Packaging is in "Waffle" trays: Quantity per tray: 36 pieces Quantity per box: 108 pieces