Resistors
MELF Resistors
WRM Series
AEC-Q200
High reliability
Predictable pulse handling capability
Tolerances down to 0.1%
TCR down to 5 ppm/°C
All parts are Pb-free and comply with EU Directive 2011/65/EU amended by (EU) 2015/863 (RoHS3)
Electrical Data
Power rating @70°C
Resistance Range
Limiting element voltage
TCR
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
Insulation resistance
Zero ohm jumper current rating
Zero ohm jumper maximum residual resistance
watts
ohms
volts
ppm/°C
%
k/W
°C
ohms
amps
mΩ
WRM 0102
0.2
1R0 - 1M0
200
15, 25, 50, 100
WRM 0204
WRM 0207
0.25
0.4
R22 -5M1
R22 - 4M7
200
250
5, 10, 15, 25, 50, 100
15, 25, 50, 100
0.1, 0.25, 0.5, 1, 5
E24 & E96
200
140
-55 to +125
>10
10
4
15
250
-55 to +155
2
Physical Data
Dimensions (mm) & weight (g)
Type
WRM 0102
WRM 0204
WRM 0207
L
max
2.3
3.7
6.1
D
max
1.35
1.55
2.4
D
1
max
1.3
1.55
2.4
K
min
0.3
0.5
0.5
L
1
min
1.1
1.5
2.9
Weight
0.01
0.02
0.08
L
D
1
L
1
K
D
Construction
A metal film is deposited onto a high dissipation ceramic
former to which tin plated teminating caps are fitted.
The resistor is adjusted to value by a helical cut in the film
and the body is protected by a lacquer coating.
Terminations
Material
Solderability
Marking
Plated steel cap.
The pure tin finish produces ageing free
contacts on which low melting solders can
be used. Dipped area shall be covered with
a smooth and bright solder coating after
3 seconds immersion at 215°C.
Resistance values are colour coded with four bands,
three indicating value and one indicating the multiplier.
(Note this describes standard marking, but certain values
may still be supplied with the addition of a tolerance
band following the multiplier.).
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuit boards.
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
www.ttelectronics.com/resistors
© TT Electronics plc
07.20
MELF Resistors
WRM Series
TCR and Tolerance Range
Type Reference
TCR
5%
1.0%
±100ppm
1R0 - 1M0
1R0 - 1M0
±50ppm
1R0 - 1M0
1R0 - 1M0
WRM0102
±25ppm
-
49R9 - 390K
±15ppm
-
100R - 56K
±100ppm
R22 - R91
-
±50ppm
-
1R - 5M1
±25ppm
-
4R7 - 500K
WRM0204
±15ppm
-
-
±10ppm
-
-
±05ppm
-
-
±100ppm
R22 - R91
-
-
1R - 4M7
±50ppm
WRM0207
±25ppm
-
10R - 1M
±15ppm
-
-
* TC 10ppm & 5ppm is specified over the temperature range -10°C to +85°C.
Tolerance
0.5%
-
8R2 - 1M0
49R9 - 200K
100R - 56K
-
10R - 1M6
10R - 500K
10R - 221K
-
-
-
10R -1M6
10R - 680K
51R1 - 10K
0.25%
-
-
100R - 82K
100R - 56K
-
22R - 332K
22R - 402K
22R - 221K
22R - 221K
100R - 100K
-
-
51R1 - 330K
51R1 - 10K
0.1%
-
-
100R - 82K
100R - 56K
-
43R - 332K
43R - 332K
43R - 221K
43R - 221K
100R - 100K
-
-
100R - 100K
100R - 10K
Performance Data
Δ R/R
Test
75R - 100K
Short time overload*
Bending test*
Resistance to soldering heat
Temperature rapid change
Endurance*
≤0.15% + 0.05Ω
≤0.3% + 0.05Ω
≤0.3% + 0.05Ω
≤0.6% + 0.05Ω
≤0.9% + 0.05Ω
≤1.8% + 0.05Ω
Climatic sequence*
≤0.5% + 0.05Ω
≤1.0% + 0.05Ω
Damp heat steady state*
≤0.5% + 0.05Ω
≤1.0% + 0.05Ω
Current noise
<0.25µV/V
<3µV/V
Solderability
>95% coverage
Voltage coefficient
0 to -0.5ppm/V
Voltage proof
No flashover or breakdown
* Resistors to be mounted on a PC-board according to IEC 115-1, clause 4.27.1.
* AEC-Q200 approval applies to all values up to and including 3M4 at TCRs above 5ppm/°C and to zero ohm jumpers.
Load life
1000h
8000h
225,000h
≤0.15% + 0.05Ω
≤0.3% + 0.05Ω
≤0.9% + 0.05Ω
≤0.25% + 0.05Ω
≤0.25% + 0.05Ω
<0.05µV/V
≤0.5% + 0.05Ω
≤1.0% + 0.05Ω
≤3.0% + 0.05Ω
≤1.0% + 0.05Ω
≤1.0% + 0.05Ω
<3µV/V
≤0.05% + 0.01Ω
≤0.05% + 0.01Ω
≤0.05% + 0.01Ω
≤0.05% + 0.01Ω
0204 and 0207
10R - <75R &
>100K - 332K
≤0.1% + 0.01Ω
≤0.1% + 0.01Ω
≤0.1% + 0.01Ω
≤0.1% + 0.01Ω
0102
<10R & >332K
≤0.25% + 0.05Ω
≤0.25% + 0.05Ω
≤0.25% + 0.05Ω
≤0.25% + 0.05Ω
All values
≤0.25% + 0.05Ω
≤0.25% + 0.05Ω
≤0.25% + 0.05Ω
≤0.25% + 0.05Ω
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
www.ttelectronics.com/resistors
© TT Electronics plc
07.20
MELF Resistors
WRM Series
Single Pulse
100
W
10
Maximum Pulse Load
WRM 0102
WRM 0204
WRM 0207
Pulse Load
P
max
1
0,1
10
µs
100
µs
1 ms
10 ms
100 ms
1s
10 s
Continuous Pulses
Maximum Pulse Load
P
max
100
W
10
Pulse Duration
t
i
WRM 0102
WRM 0204
WRM 0207
Continuous Pulse Load
1
0,1
10
µs
100
µs
1 ms
10 ms
100 ms
1s
10 s
Pulse Duration
t
i
1.2/50µs Lightning Surge
10,000
Peak Voltage (V)
1,000
WRM0204
WRM0207
100
10
10
100
1,000
10,000
100,000
1,000,000
Resistance Value (Ω)
10/700µs Lightning Surge
10,000
Peak Voltage (V)
1,000
WRM0204
WRM0207
100
10
10
100
1,000
10,000
100,000
1,000,000
Resistance Value (Ω)
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
www.ttelectronics.com/resistors
© TT Electronics plc
07.20
MELF Resistors
WRM Series
Packaging
The WRM 0102 and 0204 resistors are supplied reeled on 8mm blister tape.
WRM 0207 resistors are supplied on 12mm blister tape.
Packaging complies with the requirements of IEC 286-3.
Ordering Procedure
W
R
M
0
1
1
Type
2
TCR
2
0
Example: WRM0204C-1K0FI
(WRM0204, 50ppm/°C, 1 kilohm ±1%, Pb-free)
Example: WRM0204-R000I
(WRM0204, zero ohm jumper, Pb-free)
4
C
2
3
Value
3/4 characters
R = ohms
K = kilohms
M = megohms
-
1
K
3
4
Tolerance
0
F
4
I
5
5
Packing
I = Standard
0102
3000 / 7” reel
0204
3000 / 7” reel
1
0207
1500 / 7” reel
WRM0102 V = ±5ppm/ C
WRM0204 T = ±10ppm/ C
WRM0207 Y = ±15ppm/ C
D = ±25ppm/ C
C = ±50ppm/ C
Z = ±100ppm/ C
Omit for Jumper
B = ±0.1%
C = ±0.25%
D = ±0.5%
F = ±1%
R000 = Jumper J = ±5%
Omit for Jumper
Note 1: High precision parts may be supplied on 1000 piece reels – please enquire
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
www.ttelectronics.com/resistors
© TT Electronics plc
07.20
