Precision Metal
Film Resistors
RC series
sCECC released products with low
TCRs over a wide resistance range
sResistance tolerance down to 0.05%
sExpress delivery available
sLow 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
0.15.052.0sttawC°07 ta gnitar rewoP
Resistance range ohms 5R to 2M 5R to 2M 10R to 5M
005053053stlovegatlov tnemele gnitimiL
007005005stlovegatlov noitalosI
ecnatsiser eeS C°/mppsedoc & )C°07+ ot 02( RCT
snoitcirtser %ecnarelot ecnatsiseR
Electrical Data
02 . 08
A subsidiary of
TT electronics plc
Welwyn Components
LKKJH400-10104 CCEC devorppA
5.052.052.0521.0360.0sttawC°07 ta gnitar rewoP
Resistance range ohms 1R to 1M 1R to 1M 1R to 1M 10R to 1M 10R to 1M
053052052002002stlovegatlov tnemele gnitimiL
005053053082082stlovegatlov noitalosI
ecnatsiser eeS C°/mppsedoc & RCT
snoitcirtser %)edoc( ecnarelot ecnatsiseR
CBBA408-10104 CCEC devorppA
5.052.052.0521.0sttawC°07 ta gnitar rewoP
Resistance range ohms 1R to 1M 1R to 1M 10R to 1M 10R to 1M
053052052002stlovegatlov tnemele gnitimiL
005053053082stlovegatlov noitalosI
ecnatsiser eeS C°/mppsedoc & RCT
snoitcirtser %)edoc( ecnarelot ecnatsiseR
eulav ynAderreferp 69E ,42Eseulav dradnatS
redro ot0607011ttaw/C°ecnadepmi lamrehT
551+ ot 55-C°egnar erutarepmet tneibmA
5(V), 10(T), 15(Y) & 25(D)
15(Y) & 25(D)
15(T) & 25(E)
0.05(W), 0.1(B) & 0.25(C)
0.05(W), 0.1(B) & 0.25(C)
0.05(W), 0.1(B) & 0.25(C)
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
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 f 1 – f 2≤ 1.4 mm
175
Precision Metal
Film Resistors
RC seriesWelwyn 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
Ordering Procedure
Example: RC55 with TCR of 5ppm/ °C at 31.6 kilohms and 0.1% tolerance in an ammo pack box of up to 1000 pieces -
R C 5 5 V – 3 1 K 6 B I
Type
Trim option
Standard
N
Non-inductive
TCR
V
5 ppm/ °C
Y*
15 ppm/ °C
T
10 ppm/ °C
D*
25 ppm/ °C
* CECC40101-804 codes for 15 and 25ppm/°C
are T and E respectively.
Value (use IEC62 code)
Tolerance (use IEC62 code)
W
0.05%
B
0.1%
C
0.25%
Packing
I
Ammo
RC55, RC65
Up to1000/box
Standard
Bulk
RC70
250/box
For CECC released product state on order the CECC number and style. Example: RC55Y-31K6BI CECC40101-004 J
For SnPb finish instead of Pb-free replace the packing suffix with PB. Example: RC55V-31K6BPB
Tolerance
07CR56CR55CRRCT
0.05% .1 – .25% 0.05% .1 – .25% 0.05% .1 – .25%
ppm/°C
5 10 to 500k 10 to 500k 10 to 500k 10 to 500k 10 to 750k 10 to 750k
10 10 to 1M 10 to 1M 10 to 1M 10 to 1M 10 to 1M 10 to 1M
15 10 to 1M 5 to 1M 10 to 1M 5 to 1M 10 to 1M 10 to 2M
25 10 to 1M 5 to 2M 10 to 1M 5 to 2M 10 to 1M 10 to 5M