Metal-Oxide Varistors (MOVs) Surface Mount Varistors > SM20 Series RoHS SM20 Varistor Series Description The Littelfuse 20mm SMD Series is a surface-mount metal oxide varistor device, for use in applications requiring hi-energy / transient current capability. The AC rated parts are designed to operate continuously across AC power lines. The DC rated parts are suitable for Automotive applications. The series comprises a Nylon molded package with folded tin plated metal leads for soldering to board. The SMD Series is based on radial 20mm internal varistor element with similar characteristics to the Littelfuse LA / ZA series of varistors. Agency Approvals Features Agency Agency Approval Agency File Number UL1449 E320116 DC Voltage Rating Low voltage 26 - 420VDC devices specified for automotive load AC Voltage Rating dump energy 20Vac - 320AC Available inwaf fl No De-Rating up Additional Information tray packaging to 85C ambient Lead-Free, Halogen- Free and RoHS Compliant Datasheet Resources Samples Absolute Maximum Ratings For ratings of individual members of a series, see Device Ratings and Specifications chart Continuous SM20 Series Units Steady State Applied Voltage: AC Voltage Range (V ) 20 to 320 V M(AC)RMS DC Voltage Range (V ) 26 to 420 V M(DC) Transients: Peak Pulse Current (I ) 8/20s Current Wave, Single Pulse up to 6500 A TM Single Pulse Energy Capability (W ) 10/1000s Current Wave 165 J TM Load Dump Energy Capability (td>=30ms) 160 J O Operating Ambient Temperature Range (T ) -40 to +85 C A O Storage Temperature Range (T ) -40 to +125 C STG V O Temperature Coefficient (a ) of Clamping Voltage (V ) at Specified Test Current <0.01 %/ C C Hi-Pot Encapsulation (COATING Isolation Voltage Capability) 2500 V (Dielectric must withstand indicated DC voltage for one minute per MIL-STD 202, Method 301) COATING Insulation Resistance 1000 M 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. 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 09/09/20Metal-Oxide Varistors (MOVs) Surface Mount Varistors > SM20 Series SM20 Series Ratings & Specifications Maximum Rating (85C) Specifications (25C) Continuous Transient Varistor Voltage Maximum Clamping Typical Energy Peak Current at 1mA DC Voltage Capacitance Part V V RMS DC Branding 10 x 1000s 8 x 20s Test Current 8 x 20 s f = 1MHz Number W I TM TM V V V Min V Max V I C M(AC) M(DC) NOM NOM C PK 1x pulse 1x pulse (V) (V) (J) (A) (V) (V) (V) (A) (pF) 20 32 40 V26SM20 26SM20 20 26 2000 63 20 12000 160 (note 1) (10mA) (10mA) 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). Peak Current, Energy and Power Derating Curve Repetitive Surge Capability For applications exceeding 85C ambient temperature, the peak V175SM20 - V320SM20 surge current and energy ratings must be reduced as shown below 10,000 1 MODEL SIZE 20mm 2 5,000 10 V175SM20 - V320SM20 100 2 10 2,000 3 90 10 4 10 1,000 5 80 10 6 500 10 70 200 60 100 50 50 40 30 20 INDEFINITE 10 20 5 10 0 2 -55 50 60 70 80 90 100110 120130 140150 1 o AMBIENT TEMPERATURE ( C) 20 100 1,000 10,000 IMPULSE DURATION (s) FIGURE 1. CURRENT, ENERGY AND POWER DERATING CURVE Peak Pulse Current Test Waveform for Clamping Voltage 0 = Virtual Origin of Wave 1 T = Time from 10% to 90% of Peak T = Rise Time = 1.25 x T 100 1 T = Decay Time 2 Example - For an 8/20 s Current Waveform: 8s = T = Rise Time 1 50 20s = T = Decay Time 2 0 t TIME O 1 t 1 t 2 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 09/09/20 PERCENT OF RATED VALUE PERCENT OF PEAK VALUE Test SURGE CURRENT (A)