Features
Applications
Almost anywhere there is a low voltage
power supply, up to 72 V and a load to be
protected, including:
■ Security and fire alarm systems
■ Loudspeakers
■ 72 V rated
■ Radial leaded devices
■ Cured, flame retardant epoxy polymer
insulating material meets
UL 94V-0 requirements
R
4
X
1
0
1
S
0
1
8
■ RoHS compliant*
■ Power transformers
■ Agency recognition:
MF-RX/72 Series - PTC Resettable Fuses
Electrical Characteristics
1 Hour (R )
Post-Trip
Resistance
Tripped
Power
Dissipation
1
Initial
Resistance
Max. Time
To Trip
I
I
trip
hold
V max.
Model
I max.
Amps
Amperes
at 23 °C
Hold
Ohms
at 23 °C
Ohms
at 23 °C at 23 °C
Max.
0.38
0.30
0.22
0.19
0.13
0.10
0.08
Amperes Seconds
Watts
Volts
at 23 °C at 23 °C
Trip
Min.
Max.
0.25
0.19
0.14
0.12
0.08
0.06
0.05
Typ.
MF-RX110/72
MF-RX135/72
MF-RX160/72
MF-RX185/72
MF-RX250/72
MF-RX300/72
MF-RX375/72
72.0
72.0
72.0
72.0
72.0
72.0
72.0
40
40
40
40
40
40
40
1.10
1.35
1.60
1.85
2.50
3.00
3.75
2.20
2.70
3.20
3.70
5.00
6.00
7.50
0.15
0.12
0.09
0.08
0.05
0.04
0.03
5.5
6.75
8.0
9.25
12.5
15.0
18.75
8.2
9.6
11.4
12.6
15.6
19.8
24.0
1.50
1.70
1.90
2.10
2.50
2.80
3.20
Environmental Characteristics
Operating/Storage Temperature ........................-40 °C to +85 °C
Maximum Device Surface Temperature
in Tripped State ................................................125 °C
Passive Aging......................................................+85 °C, 1000 hours .................................... 5 ꢀ typical resistance change
Humidity Aging....................................................+85 °C, 85 ꢀ R.H. 1000 hours .................. 5 ꢀ typical resistance change
Thermal Shock....................................................+85 °C to -55 °C, 10 times ........................ 10 ꢀ typical resistance change
Solvent Resistance ............................................MIL-STD-202, Method 215 ........................No change
Vibration..............................................................MIL-STD-883C, Method 2007.1, ................No change
Condition A
Test Procedures And Requirements For Model MF-RX/72 Series
Test
Test Conditions
Accept/Reject Criteria
Visual/Mech. ......................................................Verify dimensions and materials ................Per MF physical description
Resistance ..........................................................In still air @ 23 °C........................................Rmin ≤ R ≤ Rmax
Time to Trip ........................................................5 times Ihold, Vmax, 23 °C ........................T ≤ max. time to trip (seconds)
Hold Current ......................................................30 min. at Ihold ..........................................No trip
Trip Cycle Life ....................................................Vmax, Imax, 100 cycles ..............................No arcing or burning
Trip Endurance....................................................Vmax, 48 hours ..........................................No arcing or burning
UL File Number ..................................................E 174545S
Asia-Pacific:
Europe:
Tel: +886-2 2562-4117 • Fax: +886-2 2562-4116
Tel: +41-41 768 5555 • Fax: +41-41 768 5510
The Americas: Tel: +1-951 781-5500 • Fax: +1-951 781-5700
www.bourns.com
Circuit Protection Division
*RoHS Directive 2002/95/EC Jan 27 2003 including Annex
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.