Metal-Oxide Varistors (MOVs) Surface Mount Varistors > CH Series

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1 CH Varistor Series RoHS Description CH Series transient surge suppressors are small, metal-oxide varistors (MOVs) manufactured in leadless chip form. They are intended for use in a variety of applications from low voltage DC to off-line board-level protection. These devices, which have significantly lower profiles than traditional radial lead varistors, permit designers to reduce the size and weight and increase the reliability of their equipment designs. CH Series varistors are available in a voltage range from 4V to 275V (V M(AC)RMS ), and energy ratings up to 8J. Agency Approvals Recognized under the components program of Underwriters Laboratories. Agency Agency Approval Agency File Number UL449 E326 See the Littelfuse Multilayer Suppressor Series also. Features Lead free Leadless, surface mount chip in 5 x 8mm Size Voltage ratings V M(AC)RMS 4V to 275V Supplied in tape and reel or bulk pack No derating up to 25ºC ambient High surge rated up to 4A for low voltage devices Absolute Maximum Ratings For ratings of individual members of a series, see Device Ratings and Specifications chart Continuous CH Series Units Steady State Applied Voltage: AC Voltage Range (V M(AC)RMS ) 4 to 275 V DC Voltage Range (V M(DC) ) 8 to 369 V Transient: Peak Pulse Current (I TM ) For 8/2µs Current (See Figure 2) to 4 A Single Pulse Energy Range For /µs Current Wave (W TM ). to 8. J Operating Ambient Temperature Range (T A ) -55 to +25 ºC Storage Temperature Range (T STG ) -55 to + ºC Temperature Coefficient (αv) of Clamping Voltage (V C ) at Specified Test Current <. %/ºC 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. Additional Information Datasheet Resources Samples Revised: 4/9/5

2 Device Ratings and Specifications Part Number Continuous Maximum Ratings (25ºC) V RMS V DC Energy (/µ s) Transient Peak Current (8/2µs) Varistor Voltage at ma DC Test Current Specifications (25ºC) Max Clamping Volt V C at Test Current (8/2µs) Typical Capacitance V M(AC) V M(DC) W TM I TM MIN V N(DC) MAX V C I P f=mhz (V) (V) (J) (A) (V) (V) (V) (V) (A) (pf) V22CH8 4 8 (Note 3). (Note2) V27CH V33CH * V39CH * V47CH * V56CH * V68CH * V2CH VCH V8CH VCH V22CH V24CH V36CH V39CH V43CH NOTES:. Power dissipation of transients not to exceed.25w. 2. Energy rating for impulse duration of 3ms minimum to one half of peak current value. 3. Also rated to withstand 24V for 5 minutes. 4. The Typical Capacitance is for reference only 5. *High Surge Option (up to 4A) available for relevant voltage ratings. Current, Energy and Power Derating Curve Continuous power dissipation capability is not an applicable design requirement for a suppressor, unless transients occur in rapid succession. Under this condition, 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 tempera tures as shown in this diagram. 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. PERCENT OF RATED VALUE Figure AMBIENT TEMPERATURE ( o C) FIGURE. CURRENT, ENERGY AND POWER DERATING CURVE Revised: 4/9/5

3 Peak Pulse Current Test Waveform Figure 2 PERCENT OF PEAK VALUE 9 O TT T2 TIME 3 FIGURE 2. PEAK PULSE CURRENT TEST WAVEFORM Clamping Voltage for V22CH8 V68CH8 Clamping Voltage V8CH8for V2CH8 V43CH8 VCH8 V2CH8 MAXIMUM PEAK VOLTS (V) MAXIMUM CLAMPING VOLTAGE MODEL SIZE 5 x 8mm 22 TO 56V N(DC) RATING T A = -55 o C TO 25 o C V68CH8 V56CH8 V47CH8 V39CH8 V33CH8 V27CH8 V22CH8 = Virtual Origin of Wave T = Time from % to 9% of Peak O = Virtual T = Origin Rise of Time Wave =.25 x T T = Time T 2 From = Decay % Time 4, to 9% of Peak T = Virtual Example: Front time =.25 MAXIMUM t CLAMPING VOLTAGE T 2 = Virtual Time to Half 3, Value MODEL (Impulse SIZE Duration) 5 x 8mm For an 8/2 µs Current TO Waveform: 43V Example: For an 8/2 s Current Waveform: N(DC) RATING 8µs = T 8 s = T = Virtual Front 2, T Time A = -55 o C TO 25 o C = Rise Time 2 s = T 2 = 2µs Virtual = TTime 2 = Decay to Half Time Value MAXIMUM PEAK VOLTS (V), V24CH8 V22CH8 VCH8 V43CH8 V39CH8 V36CH PEAK AMPERES (A) FIGURE 4. CLAMPING VOLTAGE FOR V2CH8 - V43CH Figure 3 PEAK AMPERES (A) Figure 4 FIGURE 3. CLAMPING VOLTAGE FOR V22CH8 - V68CH8 Pulse Rating Curves Surge Current Rating Curves for V22CH8 - V56CH8 Surge Current Rating Curves for V2CH8 - V43CH8 SURGE CURRENT (A) INDEFINITE MODEL SIZE 5 x 8mm V22CH8 - V56CH ,, IMPULSE DURATION (µs) Figure 5 Figure 6 SURGE CURRENT (A) 2,, INDEFINITE MODEL SIZE 5 x 8mm V2CH8 - V43CH8 2 2,, IMPULSE DURATION (µs) NOTE: If pulse ratings are exceeded, a shift of V N(DC) (at specified current) of more than +/-% could result. This type of shift, which normally results in a decrease of V N(DC), may result in FIGURE 5. SURGE CURRENT RATING CURVES FOR the device not meeting the original published specifications, but it does not prevent the device from continuing to function, FIGURE and 6. SURGE to provide CURRENT ample protection. RATING CURVES FOR V22CH8 - V56CH8 V2CH8 - V43CH8 Revised: 4/9/5

4 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. CH series devices have silver-platinum terminals (Ag/Pt), and the recommended solder is 62/36/2 (Sn/Pb/Ag), 6/4 (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 CH 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 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 ºC before cleaning. Lead free (Pb-free) Soldering Recommendations CH series devices have silver-platinum terminals (Ag/Pt), and the recommended Lead-free solder is 96.5/3./.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. Reflow Solder Profile 2 MAXIMUM TEMPERATURE 23 C MAXIMUM TEMPERATURE SECONDS ABOVE 83 C 23 C 4-8 <2 C/s SECONDS ABOVE 83 C PREHEAT DWELL <2 C/s PREHEAT ZONE PREHEAT DWELL.5 PREHEAT. ZONE Figure 7 FIGURE REFLOW.5 SOLDER PROFILE TEMPERATURE TEMPERATURE C C Wave Solder Profile 3 MAXIMUM WAVE 26 C 2 3 MAXIMUM WAVE 26 C 2 SECOND PREHEAT FIRST PREHEAT SECOND PREHEAT..5 FIRST PREHEAT Figure 8..5 FIGURE WAVE 2. SOLDER 2.5 PROFILE TEMPERATURE TEMPERATURE C C Lead free 3 Re-flow MAXIMUM Solder TEMPERATURE Profile 2 C, TIME WITHIN 5 C OF PEAK 2 2 SECONDS MAXIMUM 3 MAXIMUM TEMPERATURE 26 C, <3 C/s 6 - SEC TIME WITHIN 5 C OF PEAK > 27 C 2 2 SECONDS MAXIMUM <3 C/s 6 - SEC > 27 C PREHEAT ZONE PREHEAT ZONE TEMPERATURE TEMPERATURE C C Figure 9 FIGURE 4. REFLOW SOLDER PROFILE FIGURE 5. WAVE SOLDER PROFILE FIGURE 6. LEAD-FREE RE-FLOW SOLDER PROFILE FIGURE 6. LEAD-FREE RE-FLOW SOLDER PROFILE Revised: 4/9/5

5 Part Numbering System V 22 CH 8 X LITTELFUSE VARISTOR NOMINAL VARISTOR VOLTAGE SERIES DESIGNATOR PACKAGING OPTIONS No Letter: Standard 3 Inch Reel T: 7 Inch Reel S: Bulk Pack RELATIVE SIZE INDICATOR Dimensions PAD LAYOUT DIMENSIONS C Symbol Inches Millimeters Min Max Min Max A.42.2 B CHIP LAYOUT DIMENSIONS NOTE A B C D E L W NOTE: Avoid metal runs in this area. Soldering recommendations: Material - 62/36/2 Sn/Pb/ Ag or equivalent.temperature 23ºC Max., 5s. Max. Flux - R.M.A. E D L W Revised: 4/9/5

6 Tape and Reel Specifications W T R F E P P P 2 D A D PLAN VIEW OF STRIP CROSS SECTION (REF. PLANE FOR A & B ) H B R 2 A K CAVITY DETAILS R 3 B T T K K REELED RADIUS DETAILS SECTION THRU CAVITY R 4 MINIMUM BENDING RADIUS Symbol Parameter Size (mm) B Cavity Length 8.8 -/+. A Cavity Width 5.5 -/+. K Cavity Depth 2. Min. H Ref. Plane for A and B R, R 2, R 3 Tape Cavity Radii.5 Max. T Carrier Tape Thickness. Max. T Cover Tape Thickness. Max. E Sprocket Hole from Edge.75 -/+. P Sprocket Hole Pitch 4. -/+. D Sprocket Hole Diameter P 2 Hole Centre to Component Centre 2. -/+.5 R 4 Min. Bending Radius 3.5 Min. D Ejection Hole Diameter.5 Min. K Overall Thickness 3. Min. P Pitch Of Component 8. -/+. F Sprocket Hole to Ejection Hole 7.5 -/+. W Carrier Tape Width 6. -/+.3 Notes : Conforms to EIA-48-, Revision A Can be supplied to IEC P ublication Standard Packaging* Special Packaging CH Series varistors are always shipped in tape and reel. The standard 3-inch reel utilized contains 4 pieces. Note also that the CH Series receives no branding on the chip itself. *NOTE: It is recommended that parts be kept in the sealed bag provided and that parts be used as soon as possible when removed from bags. Option Option 2 7-inch reels containing pieces are available. To order 7-inch reels add a 'T' suffix to the part number; e.g., V47CH8T. For small quantities (less than pieces) the units are shipped bulk pack. To order, add a 'S' suffix to the part number; e.g., V47CH8S. Ordering Notes: X333: HIGH SURGE RATING OPTION -- Low voltage (V22~V68) standard parts high surge rating to A, to order high surge rated up to 4A with suffix X333. Example: Standard Model V33CH8 Order As V33CH8X333 Revised: 4/9/5