Metal Film Resistors
MFR Series
•Approved to BSCECC 40101-803 and 019
•Tolerances down to 0.5%
•Temperature coefficient down to 50ppm/°C
Commercial MFR3 MFR4 MFR5
Power rating at 70°C watts 0.4 0.5 0.75
Resistance range ohms 1R0 - 1M 1R0 - 10M 1R0 - 1M
Limiting element voltage volts 200 350 350
TCR ppm/°C <10 and >150K: 100* 50 ≤10:150 >10:100*
10 to 150K:50
Resistance tolerance % 1,2 0.5, 1,2 0.5, 1,2
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
* Note:- Tighter TCR’S are available, consult factory for details.
Electrical Data
Approved CECC 40101 - 019 Style GZ GX FZ FX EZ EX
Power rating at 70°C watts 0.125 0.125 0.25 0.25 0.5 0.5
Resistance range. ohms 1 to 1M 1 to 1M 1 to 1M 1 to 1M 10 to 1M0 10 to 1M
Limiting element voltage volts 175 175 250 250 350 350
TCR ppm/°C
5.1 to 9.1 : 200 5.1 to 9.1 : 500
100 250 100 250
≥10 : 100 ≥10 : 250
5.1 to 9.1 : 200 5.1 to 9.1 : 500
Resistance tolerance % 1,2 1,2 1,2 1,2 1,2 1,2
Approved CECC 40101 - 803 Style BC BK CC CK
Power rating at 70°C watts 0.125 0.125 0.25 0.25
Resistance range. ohms 10 to 1M 10 to 1M 10 to 1M 10 to 1M
Limiting element voltage volts 200 200 250 250
TCR ppm/°C 50 100 50 100
Resistance tolerance % 0.5, 1, 2 0.5, 1, 2 0.5, 1, 2 0.5, 1, 2
Standard values E24, E96 preferred
Thermal impedance °C/watt 150 140 112
Ambient temperature range °C -55 to 155
Issue B · 03.02
A subsidiary of
TT electronics plc
Welwyn Components
135
Dimensions (mm) & Weight (g)
PCB Min
mounting
Bend
Type L Max D Max f min d nom centres Radius Wt. nom
MFR3 3.5 1.8 22.4 0.5 7.6 0.5 0.1
MFR4 6.2 2.5 21.0 0.6 10.2 0.6 0.3
MFR5 9.0 3.6 19.6 0.8 12.7 1.2 0.5
Physical Data
L
Df
d
Metal Film Resistors
MFR Series
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com Issue B · 03.02
Welwyn Components
136
Graph 1 – Load for 1000 hours at 70°C: maximum changes
Graph 2 – Load for 1000 hours at 70°C: maximum changes
CECC 40101-019 Actual Performance
Requirements Maximum Typical
Load at commercial rating : 1000 hours at 70°C ∆R % 0.8 See Graph 1
Load at CECC rating : 1000 hours at 70°C ∆R % 2 0.5 See Graph 1
Shelf life : 12 months at room temperature ∆R % Not Specified 0.1 0.07
Derating zero at 155°C
Short term overload ∆R % 0.5 0.25 0.03
Climatic ∆R % 2 0.5 0.2
Climatic category 55/125/56
Long term damp heat ∆R % 2 0.5 0.3
Temperature rapid change ∆R % 0.5 0.25 0.05
Resistance to solder heat ∆R % 0.5 0.25 0.02
Vibration and bump ∆R % 0.5 0.1 0.01
Noise. (in a decade of frequency) µV/V Not specified 0.1 0.07
Insulation resistance ohms >1G >1G >1G
Voltage proof volts 350 min 400 min 400 min
Pulse handling Data available upon request
Performance Data - Type MFR 3
CECC 40101-019 CECC 40101-803 Actual Performance
Requirements Requirements Maximum Typical
Load at commercial rating :
1000 hours at 70°C ∆R % 0.8 See Graph 2
Load at CECC rating :
1000 hours at 70°C ∆R % 2 1 0.5 See Graph 2
Shelf life :
12 months at room temperature ∆R % Not specified Not Specified 0.1 0.07
Derating zero at 155°C zero at 155°C
Short term overload ∆R % 0.5 0.25 0.25 0.01
Climatic ∆R % 2 1 0.5 0.2
Climatic category 55/125/56 55/125/56
Long term damp heat ∆R % 2 1 0.5 0.3
Temperature rapid change ∆R % 0.5 0.25 0.25 0.04
Resistance to solder heat ∆R % 0.5 0.25 0.25 0.07
Vibration and bump ∆R % 0.5 0.25 0.1 0.01
Noise. (in a decade of frequency) µV/V Not Specified Not Specified 0.1 0.1
Insulation resistance ohms >1G >1G >1G >1G
Voltage proof volts 500 min 400 min 500 min 500 min
Pulse handling Data available upon request
Performance Data - Type MFR 4
Packaging
All MFR resistors are supplied tape packed ready for loading
on to automatic sequencing and insertion machines.
Component wires will not protrude beyond the outside edge
of the tapes.
Alternative packaging available by request.
Lead Formed resistors can also be supplied. Standard options
of Lancet, Radial and Goalpost forming are shown in Lead
Form Information section.
Graph 3 – Load for 1000 hours at 70°C: maximum changes
Construction
The resistance element is a precisely controlled thin film of
metal alloy sputtered on to a high purity ceramic core,
protected by a moisture-resistant, high dielectric strength
coating applied so that terminations remain completely clear.
Terminations
Material Solder-coated copper wire.
Strength The terminations meet the requirements of
IEC 68.2.21
Solderability The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2
Marking
0.5% and 1% tolerance resistors are colour coded with 5
bands, 2% tolerance has 4. IEC 62 colours are used.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuits.
52
f1f2
66
5
f1 – f2 ≤ 1.4 mm
Metal Film Resistors
MFR Series
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com Issue B · 03.02
Welwyn Components
137
CECC 40101-019 CECC 40101-803 Actual Performance
Requirements Requirements Maximum Typical
Load at commercial rating :
1000 hours at 70°C ∆R % 0.9 See Graph 3
Load at CECC rating :
1000 hours at 70°C ∆R % 2 1 0.5 See Graph 3
Shelf life :
12 months at room temperature ∆R % Not specified Not Specified 0.1 0.07
Derating zero at 155°C zero at 155°C
Short term overload ∆R % 0.5 0.25 0.25 0.01
Climatic ∆R % 2 1 0.5 0.2
Climatic category 55/125/56 55/125/56
Long term damp heat ∆R % 2 1 0.5 0.3
Temperature rapid change ∆R % 0.5 0.25 0.25 0.04
Resistance to solder heat ∆R % 0.5 0.25 0.25 0.07
Vibration and bump ∆R % 0.5 0.25 0.1 0.01
Noise. (in a decade of frequency) µV/V Not Specified Not Specified 0.1 0.07
Insulation resistance ohms >1G >1G >1G >1G
Voltage proof volts 700 min 500 min 700 min 700 min
Pulse handling Data available upon request
Performance Data - Type MFR 5
Type MFR3 MFR4 MFR5
Large ammo pack 5000 5000 2500
Standard Quantities Per Package
