Special Application Fuses
Intrinsically Safe > Surface Mount > 308 Series
Pb RoHS
308 Series 30V Intrinsically Safe Fuse
Description
The 308 Series offers a range of surface mountable
encapsulated fuses certified as intrinsically safe components
that can be used in hazardous locations. Ideal for use in oil,
gas, mine, chemical, pharmaceutical and process industries,
the 308 Series surface mountable fuse was designed to limit
the energy and temperature generated during its operation.
The fuse design and its encapsulant are suitable for use in
intrinsically safe apparatus and associated apparatus for peak
voltage not exceeding 30V.
Features
Surface Mountable Fully compatible with
lead-free solder alloys and
Encapsulated and sealed
higher temperature profiles
(0.7mm minimum)
associated with lead-free
Designed for operation in
assembly
Agency Approvals a range of hazardous area
Global hazardous locaiton
applications requiring
(haz loc) certificaitons
Agency Agency File Number Ampere Rating 30V peak
RoHS compliant
DEMKO 15 ATEX 1439U
0.250A 1.5A
II 1 G Ex ia IIC and Pb-Free
E358130 0.250A 1.5A
Applications
IECEx UL 15.0011U
0.250A 1.5A
Ex ia IIC
Testing, measuring or automation
processing electronic and
Sensors
electrical equipment
Lighting
Motor controllers
Flow/gas meters
Reference Standards
Communication handsets/
two-way radios
Certification Standards
Process control and
ATEX EN 60079-0, EN 60079-11
IECEx IEC 60079-0, IEC 60079-11
Electrical Characteristics for Series
UL 913, UL 60079-0,
UL
UL 60079-11
% of Ampere Rating Opening Time
CAN/CSA C22.2 No. 157,
cUL CAN/CSA C22.2 No. 60079-0,
100% 4 Hours, Minimum
CAN/CSA C22.2 No. 60079-11
250%* 120 Seconds, Maximum
350%** 60 Seconds, Maximum
* Applicable to 750mA - 1.5A
** Applicable to 250mA - 1.5A
Electrical Specifications by Items
Agency Approvals
Ampere Nominal Minimum Cold Minimum Cold Nominal Cold
Catalog Interrupting
Rating Amp Code Melting Resistance at Resistance at Resistance at
Number Rating
2 2
(A) I t (A Sec.) -20C (Ohms) -40C (Ohms) 25C (Ohms)
0308.250 0.250 .250 0.004 1.856 1.821 2.290 X X X
0308.375 0.375 .375 0.010 1.022 1.006 1.330 X X X
0308.500 0.500 .500 0.022 0.712 0.676 0.908 X X X
50A@24VAC
0308.750 0.750 .750 0.048 0.520 0.511 0.665 X X X
50A@30VDC
0308001. 1.00 001. 0.100 0.226 0.216 0.420 X X X
03081.25 1.25 1.25 0.220 0.240 0.236 0.318 X X X
030801.5 1.50 01.5 0.3 0.182 0.144 0.209 X X X
Notes:
1. The fuse must be mounted so that creepage and clearance distances arent impaired in any way.
2. The fuse is suitable for use in intrinsically safe equipment and associated apparatus for voltage not exceeding 30V peak.
3. Maximum surface temperature rise at 170% rated current: 250-375mA = 23C, 500mA = 35C, 750mA = 53C, 1A = 38C, 1.25-1.50A = 96C.
4. Minimum Cold Resistance at -30C is available upon request.
2019 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/04/19Special Application Fuses
Intrinsically Safe > Surface Mount > 308 Series
Temperature Rerating Curve Average Time Current Curves
140
100.000
120
100
80
10.000
60
40
-85-65 -45-25 -5 15 35 55 75 95 115135 155
1.000
TEMPERATURE (C)
Notes:
1. Re-rating depicted in this curve is in addition to the standard re-rating of 20% for continuous operation.
Example:
For continuous operation at 55C, the fuse should be rerated as follows:
I = (0.80)(0.90)I = (0.72)I
RAT RAT
0.100
2. The temperature rerating curve represents the nominal conditions. For questions about temperature
rerating curve, please consult Littelfuse technical support for assistance.
0.010
0.001 0.01 0.11 10 100
Current in Ampers
Soldering Parameters
Reflow Condition Pb Free assembly
t
P
- Temperature Min (T ) 150C
s(min)
T
P
Critical Zone
Pre Heat - Temperature Max (T ) 200C Ramp-up
s(max) T to T
L P
- Time (Min to Max) (t ) 60 180 secs
s
T
L
t
L
Average ramp up rate (Liquidus Temp (T ) to peak 3C/second max.
L
T
S(max)
T to T - Ramp-up Rate 3C/second max.
S(max) L
Ramp-down
- Temperature (T ) (Liquidus) 217C
L
Preheat
Reflow
T
S(min)
- Temperature (t ) 60 150 seconds
L
t
S
+0/5
Peak Temperature (T ) 260 C
P
Time within 5C of actual peak Temperature (t ) 30 Sec Max
p
25
time to peak temperature
Ramp-down Rate 6C/second max.
Time
(t 25C to peak)
Time 25C to peak Temperature (T ) 8 minutes max.
P
Do not exceed -
2019 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/04/19
PERCENT OF RATING
Time in Seconds
0.250A
0.375A
0.500A
0.750A
1.00A
1.25A
1.5A
Temperature