MELF Resistors
WRM Series
AEC-Q200
High reliability
Predictable pulse handling capability
Tolerances down to 0.1%
TCR down to 5 ppm/°C
BI Technologies IRC Welwyn
07.20
General Note
TT Electronics reserves the right to make changes in product specication without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
© TT Electronics plc
www.ttelectronics.com/resistors
All parts are Pb-free and comply with EU Direcve 2011/65/EU amended by (EU) 2015/863 (RoHS3)All parts are Pb-free and comply with EU Direcve 2011/65/EU amended by (EU) 2015/863 (RoHS3)
Electrical Data
WRM 0102 WRM 0204 WRM 0207
Power rang @70°C was 0.2 0.25 0.4
Resistance Range ohms 1R0 - 1M0 R22 -5M1 R22 - 4M7
Liming element voltage volts 200 200 250
TCR ppm/°C 15, 25, 50, 100 5, 10, 15, 25, 50, 100 15, 25, 50, 100
Resistance tolerance %0.1, 0.25, 0.5, 1, 5
Standard values E24 & E96
Thermal impedance k/W 250 200 140
Ambient temperature range °C -55 to +155 -55 to +125
Insulaon resistance ohms >1010
Zero ohm jumper current rang amps 2 4
Zero ohm jumper maximum residual resistance mΩ 15
Physical Data
Dimensions (mm) & weight (g)
Type L
max
D
max
D1
max
K
min
L1
min Weight
WRM 0102 2.3 1.35 1.3 0.3 1.1 0.01
WRM 0204 3.7 1.55 1.55 0.5 1.5 0.02
WRM 0207 6.1 2.4 2.4 0.5 2.9 0.08
L
K
L1
D
D1
Construcon
A metal lm is deposited onto a high dissipaon ceramic
former to which n plated teminang caps are ed.
The resistor is adjusted to value by a helical cut in the lm
and the body is protected by a lacquer coang.
Marking
Resistance values are colour coded with four bands,
three indicang value and one indicang the mulplier.
(Note this describes standard marking, but certain values
may sll be supplied with the addion of a tolerance
band following the mulplier.).
Terminaons
Material Plated steel cap.
Solderability The pure n nish produces ageing free
contacts on which low melng solders can
be used. Dipped area shall be covered with
a smooth and bright solder coang aer
3 seconds immersion at 215°C.
Solvent Resistance
The body protecon and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuit boards.
Resistors
WRM Series
BI Technologies IRC Welwyn
07.20
General Note
TT Electronics reserves the right to make changes in product specication without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
© TT Electronics plc
www.ttelectronics.com/resistors
TCR and Tolerance Range
Type Reference TCR Tolerance
5% 1.0% 0.5% 0.25% 0.1%
WRM0102
±100ppm 1R0 - 1M0 1R0 - 1M0 ---
±50ppm 1R0 - 1M0 1R0 - 1M0 8R2 - 1M0 - -
±25ppm - 49R9 - 390K 49R9 - 200K 100R - 82K 100R - 82K
±15ppm - 100R - 56K 100R - 56K 100R - 56K 100R - 56K
WRM0204
±100ppm R22 - R91 ----
±50ppm - 1R - 5M1 10R - 1M6 22R - 332K 43R - 332K
±25ppm - 4R7 - 500K 10R - 500K 22R - 402K 43R - 332K
±15ppm - - 10R - 221K 22R - 221K 43R - 221K
±10ppm - - - 22R - 221K 43R - 221K
±05ppm - - - 100R - 100K 100R - 100K
WRM0207
±100ppm R22 - R91 ----
±50ppm - 1R - 4M7 10R -1M6 - -
±25ppm - 10R - 1M 10R - 680K 51R1 - 330K 100R - 100K
±15ppm - - 51R1 - 10K 51R1 - 10K 100R - 10K
* TC 10ppm & 5ppm is specied over the temperature range -10°C to +85°C.
Performance Data
Test
Δ R/R
0204 and 0207 0102
75R - 100K 10R - <75R &
>100K - 332K <10R & >332K All values
Short me overload* ≤0.05% + 0.01Ω ≤0.1% + 0.01Ω ≤0.25% + 0.05Ω ≤0.25% + 0.05Ω
Bending test* ≤0.05% + 0.01Ω ≤0.1% + 0.01Ω ≤0.25% + 0.05Ω ≤0.25% + 0.05Ω
Resistance to soldering heat ≤0.05% + 0.01Ω ≤0.1% + 0.01Ω ≤0.25% + 0.05Ω ≤0.25% + 0.05Ω
Temperature rapid change ≤0.05% + 0.01Ω ≤0.1% + 0.01Ω ≤0.25% + 0.05Ω ≤0.25% + 0.05Ω
Endurance*
Load life 1000h
8000h
225,000h
≤0.15% + 0.05Ω
≤0.3% + 0.05Ω
≤0.9% + 0.05Ω
≤0.15% + 0.05Ω
≤0.3% + 0.05Ω
≤0.9% + 0.05Ω
≤0.3% + 0.05Ω
≤0.6% + 0.05Ω
≤1.8% + 0.05Ω
≤0.5% + 0.05Ω
≤1.0% + 0.05Ω
≤3.0% + 0.05Ω
Climac sequence* ≤0.25% + 0.05Ω ≤0.5% + 0.05Ω ≤1.0% + 0.05Ω ≤1.0% + 0.05Ω
Damp heat steady state* ≤0.25% + 0.05Ω ≤0.5% + 0.05Ω ≤1.0% + 0.05Ω ≤1.0% + 0.05Ω
Current noise <0.05µV/V <0.25µV/V <3µV/V <3µV/V
Solderability >95% coverage
Voltage coecient 0 to -0.5ppm/V
Voltage proof No ashover 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.
MELF Resistors
100
10
1
0,1
10 µs 100 µs 1 ms 10 ms 100 ms 1 s 10 s
Pulse Duration ti
Pulse Load P
max
WRM 0102
WRM 0204
WRM 0207
W
100
10
1
0,1
10 µs 100 µs 1 ms 10 ms 100 ms 1 s 10 s
Pulse Duration ti
Continuous Pulse Load P
max
WRM 0102
WRM 0204
WRM 0207
W
10
100
1,000
10,000
10 100 1,000 10,000 100,000 1,000,000
Peak Voltage (V)
Resistance Value (Ω)
1.2/50µs Lightning Surge
WRM0204
WRM0207
10
100
1,000
10,000
10 100 1,000 10,000 100,000 1,000,000
Peak Voltage (V)
Resistance Value (Ω)
10/700µs Lightning Surge
WRM0204
WRM0207
WRM Series
BI Technologies IRC Welwyn
07.20
General Note
TT Electronics reserves the right to make changes in product specication without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
© TT Electronics plc
www.ttelectronics.com/resistors
Single Pulse
Maximum Pulse Load
Connuous Pulses
Maximum Pulse Load
MELF Resistors
WRM Series
BI Technologies IRC Welwyn
07.20
General Note
TT Electronics reserves the right to make changes in product specication without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
© TT Electronics plc
www.ttelectronics.com/resistors
Ordering Procedure
Example: WRM0204C-1K0FI (WRM0204, 50ppm/°C, 1 kilohm ±1%, Pb-free)
Example: WRM0204-R000I (WRM0204, zero ohm jumper, Pb-free)
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.
W
R
M
0
2
0
4
C
-
1
K
0
F
I
1
2
4
5
1
2
3
4
5
Type TCR Value Tolerance Packing
WRM0102
V = ±5ppm/ C
3/4 characters
R = ohms
K = kilohms
M = megohms
B = ±0.1%
I = Standard
WRM0204
T = ±10ppm/ C
C = ±0.25%
0102
3000 / 7” reel
WRM0207
Y = ±15ppm/ C
D = ±0.5%
0204
3000 / 7” reel1
D = ±25ppm/ C
F = ±1%
0207
1500 / 7” reel
C = ±50ppm/ C
R000 = Jumper
J = ±5%
Z = ±100ppm/ C
Omit for Jumper
Omit for Jumper
Note 1: High precision parts may be supplied on 1000 piece reels – please enquire
MELF Resistors