Precision Metal
Film Resistors
RC series
CECC released products with low
TCRs over a wide resistance range
Resistance tolerance down to 0.05%
Express delivery available
Low noise and negligible voltage coefficient
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
173
RC55 RC65 RC70 Notes
Commercial
Power rating at 70°C watts 0.25 0.5 1.0
Resistance range ohms 1R to 4M 1R to 4M 1R to 10M
Limiting element voltage volts 350 350 500
Isolation voltage volts 500 500 700
TCR (20 to +70°C) & codes ppm/°C 5(V), 10(T), 15(Y), 25(D), 50(C) & 100(Z) See resistance
Resistance tolerance % 0.05(W), 0.1(B), 0.25(C), 0.5(D) & 1(F) restrictions
Electrical Data
Issue B · 03.02
A subsidiary of
TT electronics plc
Welwyn Components
Approved CECC 40101-004 H J K K L
Power rating at 70°C watts 0.063 0.125 0.25 0.25 0.5
Resistance range ohms 1R to 1M 1R to 1M 1R to 1M 10R to 1M 10R to 1M
Limiting element voltage volts 200 200 250 250 350
Isolation voltage volts 280 280 350 350 500
TCR & codes ppm/°C 15(Y), 25(D), 50(C) & 100(Z) See resistance
Resistance tolerance (code) % 0.05(W), 0.1(B), 0.25(C), 0.5(D) & 1(F) restrictions
Approved CECC 40101-804 A B B C
Power rating at 70°C watts 0.125 0.25 0.25 0.5
Resistance range ohms 1R to 1M 1R to 1M 10R to 1M 10R to 1M
Limiting element voltage volts 200 250 250 350
Isolation voltage volts 280 350 350 500
TCR & codes ppm/°C 15(T), 25(E) & 50(C) See resistance
Resistance tolerance (code) % 0.05(W), 0.1(B), 0.25(C), 0.5(D) & 1(F) restrictions
Standard values E24, E96 preferred Any value
Thermal impedance °C/watt 110 70 60 to order
Ambient temperature range °C -55 to +155
CECC 40101-004 CECC 40101-804
*Actual Performance
Requirements Requirements Maximum Typical
Load at commercial rating: 1000 hours at 70°C R% 0.3 0.1
Load at CECC rating: 1000 hours at 70°C R% 0.5 0.5 0.3 0.05
Dry heat: 1000 hours at 155°C R% 0.5 0.5 **1.0 0.15
Shelf life: 12 months at room temperature R% Not specified Not specified 0.1 0.03
Derating from rated power at 70°C Zero at 155°C 50% at 125°C
Short term overload R% 0.1 0.1 0.1 0.02
Climatic R% 0.5 0.5 0.3 0.1
Climatic category 55/155/56 55/125/56 55/155/56
Long term damp heat R% 0.5 0.5 0.5 0.1
Temperature rapid change R% 0.1 0.1 **0.2 0.05
Resistance to solder heat R% 0.1 0.1 0.06 0.03
Vibration and bump R% 0.1 0.1 0.06 0.02
Noise (in a decade of frequency) µV/V Not specified Not specified 1.0 0.1
Voltage coefficient of resistance ppm/V Not specified Not specified <1
Construction
A metal film is deposited onto a high quality ceramic former.
Nickel-plated steel caps are force fitted to the former and
termination wires are welded to the caps.
The resistor is adjusted to value by a helical cut in the film
and the body is protected with a specially formulated epoxy
coating.
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.
Precision Metal
Film Resistors
RC 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
174
Issue B · 03.02
Welwyn Components
Marking
Type reference, TCR code, resistance value and
tolerance code.
The resistance values conform to IEC 62.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuits.
Performance Data
Note: *An 0.01 ohm addition to be added to the performance claims of all resistors <10R.
** All products within the specified approved range meet CECC requirements.
Dimensions (mm) & Weight (g)
PCB Min.
mounting Bend
Type L max D max f min d nom centres Radius Wt. nom
RC55 7.2 2.5 30 0.6 10.2 0.6 0.24
RC65 10.0 3.7 30 0.6 12.7 0.6 0.40
RC70 15.5 5.5 30 0.8 18.4 1.2 1.15
Physical Data
L
Df
d
Application Notes
Matched Sets and Networks
Welwyn has many years experience in the supply of matched
set of precision resistors.
Resistors can be supplied matched for tolerance and TCR
down to ±0.02% and ±2ppm/°C, either as separate resistors
or pre-assembled and encapsulated within a plastic box.
The individual resistors within a set or module can be
manufactured with a tolerance of ±0.05% and TCR of
±5ppm/°C.
A low inductance version is available at 1% tolerance.
For low inductance version add suffix N.
Packaging
The standard method of packaging RC55 resistors is taped in
ammo packs. Taped resistors on reel or loose packed
components can also be supplied by special request. The
standard packaging for RC65 and RC70 resistors is loose in
boxes. By special request the RC65 components can also be
supplied taped on reel or in ammo pack. In the case of tape
packed components the usable lead length is reduced by the
width of the tape.
52
f1f2
66
5
Body location f1 – f2 1.4 mm
Standard Quantities Per Package
Type RC55 RC65 RC70
Small box 250 125 25
Large box 1000 500 250
Reel 5000 2500 -
Large ammo pack 1000 1000 -
175
Tolerance
TCR RC55 RC65 RC70
ppm/°C 0.05% .1 – .25% .5 – 1% 0.05% .1 – .25% .5 – 1% 0.05% .1 – .25% .5 – 1%
5 10 to 500k 10 to 500k 1 to 500k 10 to 500k 10 to 500k 1 to 500k 10 to 750k 10 to 750k 1 to 750k
10 10 to 1M 10 to 1M 1 to 1M 10 to 1M 10 to 1M 1 to 1M 10 to 1M 10 to 1M 1 to 1M
15 10 to 1M 5 to 1M 1 to 1M 10 to 1M 5 to 1M 1 to 1M 10 to 1M 10 to 2M 1 to 2M
25 10 to 1M 5 to 2M 1 to 2M 10 to 1M 5 to 2M 1 to 2M 10 to 1M 10 to 5M 1 to 5M
50 10 to 1M 5 to 2M 1 to 4M 10 to 1M 5 to 2M 1 to 4M 10 to 1M 5 to 10M 1 to 10M
100 10 to 1M 1 to 2M 1 to 4M 10 to 1M 1 to 2M 1 to 4M 10 to 1M 1 to 10M 1 to 10M
Precision Metal
Film Resistors
RC series Welwyn Components
Table of Resistance Restrictions
© 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