1. PRODUCT SELECTION & COMPARISON
Surface Mount Chip Fuses

2. Fuse is over-current protection device
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. 1.) Circuit Voltage & Voltage Rating:
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 +25℃) for a least 4 hours
Rule of thumb - operate at no more than 75% of fuse current +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. 4.) Ambient Temperature:
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. 6.) Maximum Available Fault Current:
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 I2t characteristics 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 I2t characteristics 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 I2t value 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. 7.) Pulse Current Characteristics
PRODUCT TRAINING
SMT Fuses
7.) Pulse Current Characteristics
Use the correct formula, shown above, to determine the required I2t characteristics of the fuse

7. 7.) Pulse Current Characteristics
PRODUCT TRAINING
SMT Fuses
7.) Pulse Current Characteristics
Pulse factor ‘Fp’
Correct the I2t required, based upon the number of pulse cycles as seen by the fuse (see above curve)
Example: 1000 cycles derate I2t to 50%
Example: 100,000 cycles derate I2t to 25%

8. ② Derate for temperature factor
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 + 80℃
1.3A / 0.75 / 0.91 = 1.905A
+ 80℃

9. 100K pulses 4Amp square wave for 10mS
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 + 80℃
1.3A / 0.75 / 0.91 = 1.905A
+ 80℃

10. 100K pulses 4Amp square wave for 10mS
PRODUCT TRAINING
SMT Fuses
Operating + 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. Wire-In-Air SMT Fuses Types Thick Film NFVC NFCC / NFHC / NFSC series
Termination
(Cap)
Ceramic body
Solder dome
Melting wire
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. Thickness (low profile)
SMT Fuses Types
Technology
Typical Case Sizes
Thick Film
1206, 0805, 0603, 0402
Wire-In-Air
(WIA)
2410 (6125)
Thick Film
NFCC / NFHC / NFSC
series
Wire-In-Air
NFVC
series
Wire-In-Air
Thick Film Thin Film
Voltage Rating  -
High Current Rating 
Anti-Inrush (I2t)
Size (small)
Thickness (low profile)
Cost
Automated Production

13. NEW NIC Part Numbers Metric Size English Size Rated Current (A)
Rated Voltage(VAC)
Fusing Type
Littelfuse
Bussmann
KOA
AEM
Conquer
NFVC6125F1R00TRF
6125
2410 1
125
fast
6125FF1-R
CCF1NTE1
AF2-1.00V125T
SEF 001
NFVC6125F1R25TRF
1.25
6125FF1.25-R
CCF1NTE1.25
AF2-1.25V125T
NFVC6125F1R60TRF
1.6
6125FF1.5-R
CCF1NTE1.6
SEF 1.50
NFVC6125F2R00TRF 2
6125FF2-R
CCF1NTE2
AF2-2.00V125T
SEF 002
NFVC6125F2R50TRF
2.5
6125FF2.5-R
CCF1NTE2.5
AF2-2.50V125T
SEF 2.50
NFVC6125F3R15TRF
3.15
6125FF3-R
CCF1NTE3.15
AF2-3.15V125T
SEF 003
NFVC6125F4R00TRF 4
6125FF4-R
CCF1NTE4
AF2-4.00V125T
SEF 004
NFVC6125F5R00TRF 5
6125FF5-R
CCF1NTE5
AF2-5.00V125T
SEF 005
NFVC6125F6R30TRF
6.3
6125FF6.3-R
CCF1NTE6.3
AF2-6.30V125T
SEF 006
NFVC6125F7R00TRF 7
6125FF7-R
AF2-7.00V125T
SEF 007
NFVC6125F8R00TRF 8
6125FF8-R
CCF1NTE8
AF2-8.00V125T
SEF 008
NFVC6125F10R0TRF 10
6125FF10-R
CCF1NTE10
AF2-10.0V125T
SEF 010
NFVC6125F12R0TRF 12 65
6125FF12-R
AF2-12.0V125T
SEF 012
NFVC6125F15R0TRF 15
6125FF15-R
AF2-15.0V125T
SEF 015
NFVC6125F20R0TRF 20
AF2-20.0V125T

14. High InRush High InRush
NIC Part Numbers
Size
Rated Current (A)
Rated Voltage (VAC)
Fusing Type
Littelfuse
Bussmann
KOA
AEM
Conquer
NFVC6125H1R00TRF
6125
2410 1
250V
High Inrush NA
MF2410F1.000TM
CQ24PT 001
NFVC6125H1R25TRF
1.25
MF2410F1.250TM
NFVC6125H1R50TRF
1.5
CQ24PT 1.50
NFVC6125H1R60TRF
1.6
MF2410F1.600TM
NFVC6125H2R00TRF 2
MF2410F2.000TM
CQ24PT 002
NFVC6125H2R50TRF
2.5
CQ24PT 2.50
NFVC6125H3R00TRF 3
CQ24PT 003
NFVC6125H3R15TRF
3.15
NFVC6125H3R50TRF
3.5
NFVC6125H4R00TRF 4
CQ24PT 004
NFVC6125H5R00TRF 5
CQ24PT 005
NFVC6125S1R00TRF
125V
6125TD1-R
SET 001
NFVC6125S1R25TRF
NFVC6125S1R50TRF
6125TD1.5-R
SET 1.50
NFVC6125S1R60TRF
NFVC6125S2R00TRF
6125TD2-R
SET 002
NFVC6125S2R50TRF
6125TD2.5-R
SET 2.50
NFVC6125S3R00TRF
6125TD3-R
SET 003
NFVC6125S3R15TRF
SET 3.15
NFVC6125S3R50TRF
6125TD3.5-R
SET 3.50
NFVC6125S4R00TRF
6125TD4-R
SET 004
NFVC6125S5R00TRF
6125TD5-R
SET 005
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 / 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 Littelfuse 0451 Comparison
DESC: Fast Acting SMT Fuses
Technology
Specifications
Structure & Dimensions
DCR / 2In / I2T / Thermal Shock / Surface Temperature Rise
Summary

18. and good reliability. 4.Excellent solder ability
Comparison
Company
NIC
Littelfuse
P/N
NFVC6125F1R00TRF
MRL
Structure
Advantage
1.Excellent thermal conductivity 2.Excellent anti-surge capability 3. Stable fusing time
and good reliability. 4.Excellent solder ability
5.Low surface temperature rise
6.Full automated production line
1.Excellent thermal conductivity 2. Stable fusing time
and good reliability 3.Excellent solder ability
Disadvantage
1. Production capacity
1. High surface temperature rise
2. Long Lead-time
3. Non-automated production line

19. Structure Comparison Table for 1A Rating
Comparison: Structure & Dimensions
Structure Comparison Table for 1A Rating
External View
NIC
Littelfuse
Internal View
Wire Structure
Ceramic
Curved-wire
FINDING:
Similar Construction
1.Dimension Specification
Company
L(mm)
W(mm)
T(mm)
t(mm)
NIC
6.1±0.20
2.50±0.10
2.50±0.1
1.40±0.10
Littelfuse
6.1
2.69
1.45
2. Component Measurement
Company
L(mm)
W(mm)
T(mm)
t(mm)
NIC
6.00
2.56
2.55
1.33
Littelfuse
2.57
1.42
FINDING:
Same size
Same PCB footprint and same PCB layout

20. Advantage: NIC NFVC Lower DCR Higher I2t
Comparison: Specifications
Company PN
AMP
(A)
Rated
Voltage(V)
Nominal
DCR
(Ω)
I2t
(A2S)
Interrupting
Voltage
(AC/DC)
NIC
NFVC6125F1R00TRF 1
125V AC
160V DC
0.080
0.56
125/160
Littelfuse
MRL
125V DC
0.153
0.459
125/125
Advantage: NIC NFVC
Lower DCR
Higher I2t

21. NIC NFVC6125F1R00TRF has lower DCR than Littelfuse 04511001.MRL
Comparison: Typical DCR
1.DCR Spec.
Company PN
AMP(A)
Nominal DCR(Ω)
NIC
NFVC6125F1R00TRF 1
0.080
Littelfuse
MRL
0.153
2.Typical DCR Measurements; n = 20
Little Fuse MRL
DC Resistance (mΩ)
NIC NFVC6125F1R00TRF
FINDING:
NIC NFVC6125F1R00TRF has lower DCR than Littelfuse MRL

22. Test Result Test Condition: 10 A Current FINDINGS:
Comparison: Typical I2T
I2T = The thermal energy level causing melting (opening) of the fuse element.
Company
NIC
Littelfuse
Spec. I2T
0.56 (A2S)
0.459 (A2S)
Test Condition: 10 A Current
Test Result
NIC
Littelfuse
sample
10In (mS)
I2t (A2S) 1
5.560
0.556
3.76
0.376 2
5.480
0.548
4.08
0.408 3
5.380
0.538 4
5.220
0.522
3.92
0.392 5
5.060
0.506
4.24
0.424
Avg.
5.34
0.542
4.02
0.402
FINDINGS:
I2T of NIC NFVC6125F1R00TRF is better than Littelfuse 451
NIC NFVC6125F1R00TRF has better anti-surge capability

23. Spec: 2In rated current ≤ 5 Seconds
Comparison: Typical Fusing Time
Test Condition
Loading current = 2A
Spec: 2In rated current ≤ 5 Seconds
Test Result
Time: Seconds
S/N
NIC
Littelfuse 1
0.210
0.102 2
0.122 3
0.195
0.115 4
0.248
0.140 5
0.203
0.132
Avg.
0.213
FINDINGS:
Fusing times are very similar … all less than 0.5 seconds

24. 5 Cycles between -55℃/+125℃, 60 minutes @ each extreme
Comparison: Thermal Shock
DCR Change with Thermal Cycle
Test Condition
5 Cycles between -55℃/+125℃, 60 minutes @ each extreme
NIC
Littelfuse
NFVC6125F1R00TRF
MRL
S/N　
initial
after
change(%) 1
84.14
83.90
-0.29%
138.2
138.6
0.29% 2
83.79
83.53
-0.31%
136
136.4 3
82.91
82.77
-0.17%
152.8
153.4
0.39% 4
82.65
82.48
-0.21%
140.4
140.9
0.36% 5
79.74
79.48
-0.33%
131
131.6
0.46%
MIN
MAX
AVG
82.43
0.26%
139.68
140.18
FINDINGS:
NIC NFVC has better thermal cycle performance than Littelfuse 451

25. Test equipment Test Condition Room Temp. +20℃ Current(A) 1.25A
Comparison: Surface Temperature Rise
Test Condition
Room Temp.
+20℃
Current(A)
1.25A
Time(min)
60min
Test equipment

26. Company NIC Littelfuse +43°C +83°C Surface Temperature of Fuse
Comparison: Surface Temperature Rise
Company
NIC
Littelfuse
Surface Temperature of Fuse
+43°C
+83°C
Higher heating … Littelfuse element use Fe/Ni/Ag alloy material. It has higher internal resistance, so the temperature rise is higher than NIC NFVC
Fe (68.18%)
Ni (34.82%)
Ag(93.55%)
FINDINGS:
NIC NFVC has lower self-heating than Littelfuse 451

27. Performance NIC NFVC Littelfuse 0451 DCR Excellent Good
Comparison: Summary
Performance
NIC NFVC
NFVC6125F1R00TRF
Littelfuse 0451
MRL
DCR
Excellent
Good
2In Fusing Time
I2T
Thermal Shock
Surface Temp. Rise
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. NIC has broad offering in Performance Passives
Technical & Sales Support
NIC has broad offering in Performance Passives
Additional Information Needed?
Need Samples?
Technical Support:
Sales Support:
European Engineering Support
North America Engineering Support
SE Asia Engineering Support