PRODUCT SELECTION & COMPARISON Surface Mount Chip Fuses - PowerPoint PPT Presentation

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PRODUCT SELECTION & COMPARISON Surface Mount Chip Fuses

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PRODUCT SELECTION & COMPARISON Surface Mount Chip Fuses
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PRODUCT SELECTION & COMPARISON Surface Mount Chip Fuses

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  1. PRODUCT SELECTION & COMPARISON Surface Mount Chip Fuses

  2. PRODUCT TRAINING SMT Fuses • Fuse is over-current protection device • Under adverse over-current conditions the fuse operates to ‘open’ and protect the electronic equipment from damage due to excessive current flow • The goal in selection the proper fuse is to select device rating which will operate trouble-free until adverse conditions occur • In ideal case, need to know the following information to make the best fuse selection Circuit voltage (VDC or VAC) Nominal operating current Interrupting Rating Ambient Temperature Overload Conditions & Opening Times Maximum available fault current Inrush, Pulse or Surge current waveform

  3. PRODUCT TRAINING SMT Fuses • 1.) Circuit Voltage & Voltage Rating: • Maximum operating voltage should not exceed the fuse rated voltage •  NFVC6125F = 125VAC/160VDC (up to 10A); 65VAC/ (above 10A) •  NFVC6125H = 250VAC (all ratings) • NFVC6125S = 125VAC (all ratings) • Rule of thumb - DO NOT use 125VAC rated fuse in circuit application operating at greater than 125VAC • 2.) Normal Operating Current • Fuses must function without opening, under rated current conditions (rated current @ +25℃) for a least 4 hours • Rule of thumb - operate at no more than 75% of fuse current rating @ +25℃ • 3.) Interrupt Rating: • Interrupt rating can also be referenced as 'breaking capacity' or 'short circuit rating‘ of the fuse, and is a safety rating for the maximum current that can safely be interrupted by the fuse under rated voltage. • Rule of thumb - A fuse with a low interrupting rating should NOT be used in circuit applications where higher fault current could exist, as the fuse could fail potentially cause a safety hazard (i.e. arcing, fire or fracture) upon opening

  4. PRODUCT TRAINING SMT Fuses • 4.) Ambient Temperature: • When operating at temperatures above or below +25℃, please refer to the temperature derating curve found on product specifications • Rule of thumb – Derate the current rating of the fuse with increasing operating temperature • 5.) Overload Conditions and Opening Times: • Electrical overload condition is abnormal excessive current flow condition within the electrical circuit, which exceeds the circuit’s normal full load current condition. • For fuses, the first overload condition point is typically 200% to 300% of fuse current rating Overload curve, at left, shows 1.0A fuse opening in one second with between 200% ~ 300% (2.0A ~ 3.0A) applied

  5. PRODUCT TRAINING SMT Fuses • 6.) Maximum Available Fault Current: • (as referenced in #3 above) The interrupt rating of the fuse must meet or exceed the maximum fault current of the circuit. • Rule of thumb - A fuse with a low interrupting rating should NOT be used in circuit applications where higher fault current could exist, as the fuse could fail potentially cause a safety hazard upon opening • 7.) Pulse Current Characteristics • Transient pulse current is used to describe current waveform shapes resulting from start-up, in-rush, pulse, surge or transient currents within a circuit. Transient pulse currents will produce thermal cycling and possible mechanical failure of the fuse. • Capability of a fuse to withstand surge pulse conditions can be determined from the I2tcharacteristics of the fuse. Melting I2t, is the thermal energy level causing melting (opening) of the fuse element. Fuse component size, materials and construction will establish the I2tcharacteristics of the fuse. • Rule of thumb - Slow blow type fuses are suggested for high in-rush and pulse current applications • Rule of thumb. The circuit designer needs to properly size the fuse based upon the fuse melting I2tvalue being greater than the pulse current I2t divided by the pulse factor Fp (see page 7) … Typically the selected fuse should have melting I2t value much greater than the I2t value of the pulse (See pages 6 & 7)

  6. PRODUCT TRAINING SMT Fuses 7.) Pulse Current Characteristics Use the correct formula, shown above, to determine the required I2tcharacteristics of the fuse

  7. PRODUCT TRAINING SMT Fuses 7.) Pulse Current Characteristics Pulse factor ‘Fp’ Correct the I2trequired, based upon the number of pulse cycles as seen by the fuse (see above curve) Example: 1000 cycles derate I2tto 50% Example: 100,000 cycles derate I2tto 25%

  8. PRODUCT TRAINING SMT Fuses Fuse Selection (non-pulse applications) Establish the circuit values: operating current, in-rush current waveform and determine operating temperature Use derating factors : ① Derate 75% (0.75) ② Derate for temperature factor Temperature Derating Example: Operating 1.3A @ + 80℃ 1.3A / 0.75 / 0.91 = 1.905A + 80℃

  9. PRODUCT TRAINING SMT Fuses Fuse Selection (pulse applications) Pulse Example: 1.905A Calculate I2t needed based upon pulse type (see page 6), and correct I2t for number of pulses (see page 7) Establish the circuit values: operating current, in-rush current waveform and determine operating temperature Pulse Example: 100K pulses 4Amp square wave for 10mS I2t = (4A)2 x 10mS = 0.16 Corrected for 100K pulses (Fp = 25%) = 0.64 Select fuse with I2t >0.64 Use derating factors : ① Derate 75% (0.75) ② Derate for temperature factor Temperature Derating Example: Operating 1.3A @ + 80℃ 1.3A / 0.75 / 0.91 = 1.905A + 80℃

  10. PRODUCT TRAINING SMT Fuses Operating 1.3A @ + 80℃ 1.3A / 0.75 / 0.91 = 1.905A Pulse Example: 100K pulses 4Amp square wave for 10mS I2t = (4A)2 x 10mS = 0.16 Corrected for 100K pulses = 0.64 Select fuse with I2t >0.64 Suggested PN: NFVC6125F2R00TRF 2.0A rated with I2t of 1.34 (A2S)

  11. Ceramic body Solder dome Termination (Cap) Melting wire SMT Fuses Types Thick Film Wire-In-Air NFVC series NFCC / NFHC / NFSC series • Thick Film construction advantages • Small size • Low Profile • Lower Cost • Range of current ratings offered • Wire-In-Air construction advantages • Consistent melting characteristic • Length and diameter of the melting wire can be adjusted to meet many different applications • Excellent inrush capability • Good lightning immunity (1.2KV lightning test)

  12. SMT Fuses Types Thick Film NFCC / NFHC / NFSC series Wire-In-Air NFVC series

  13. NEW

  14. High InRush High InRush

  15. NFCC & NFHC Series Secondary Voltage (low voltage; fast acting) Chip Fuses • COMPETITORS / CHIP FUSES: • Belfuse Fast acting C2Q (0603) / C1Q (1206) ... Slow blow C1S (1216) • Cooper Bussman CC06 / CC12H / 3216FF • Vishay MFU Series - 0402 / 0603 / 0805 / 1206 / & TFU 0603 JDYX2.E302168 Fuses, Supplemental – Component

  16. NSFC Series Secondary Voltage (low voltage; 32V; slower acting) Chip Fuses JDYX2.E302168 Fuses, Supplemental - Component

  17. PRODUCT COMPARISON • NIC Components NFVC6125 to Littelfuse0451 Comparison • DESC: Fast Acting SMT Fuses • Technology • Specifications • Structure & Dimensions • DCR / 2In / I2T / Thermal Shock / Surface Temperature Rise • Summary

  18. Comparison

  19. Comparison: Structure & Dimensions Structure Comparison Table for 1A Rating • FINDING: • Similar Construction 1.Dimension Specification 2. Component Measurement • FINDING: • Same size • Same PCB footprint and same PCB layout

  20. Comparison: Specifications • Advantage: NIC NFVC • Lower DCR • Higher I2t

  21. Comparison: Typical DCR 1.DCR Spec. 2.Typical DCR Measurements; n = 20 Little Fuse 04511001.MRL DC Resistance (mΩ) NIC NFVC6125F1R00TRF • FINDING: • NIC NFVC6125F1R00TRF has lower DCR than Littelfuse 04511001.MRL

  22. Comparison: Typical I2T I2T = The thermal energy level causing melting (opening) of the fuse element. Test Condition: 10 A Current Test Result • FINDINGS: • I2T of NIC NFVC6125F1R00TRF is better than Littelfuse 451 • NIC NFVC6125F1R00TRF has better anti-surge capability

  23. Comparison: Typical Fusing Time Spec: 2In rated current ≤ 5 Seconds Test Result Time: Seconds • FINDINGS: • Fusing times are very similar … all less than 0.5 seconds

  24. Comparison: Thermal Shock DCR Change with Thermal Cycle • FINDINGS: • NIC NFVC has better thermal cycle performance than Littelfuse 451

  25. Comparison: Surface Temperature Rise Test equipment

  26. Comparison: Surface Temperature Rise Fe (68.18%) Ni (34.82%) Ag(93.55%) Higher heating … Littelfuse element use Fe/Ni/Ag alloy material. It has higher internal resistance, so the temperature rise is higher than NIC NFVC • FINDINGS: • NIC NFVC has lower self-heating than Littelfuse 451

  27. Comparison: Summary SUMMARY: NFVC6125 series products have excellent performance, superior to Little fuse in above performance comparison, and are compatible as replacement with Littelfuse 451 type

  28. Technical & Sales Support NIC has broad offering in Performance Passives Additional Information Needed? Need Samples? Technical Support: tpmg@niccompcom Sales Support: sales@niccomp.com • European Engineering Support • North America Engineering Support • SE Asia Engineering Support