MELF Resistors WRM Series
The WRM Series MELF resistors from TT Electronics are designed for high reliability and defined pulse handling capability. They are AEC-Q200 qualified and available with tolerances down to 0.1% and TCRs down to 5ppm/C. All parts are Pb-free and comply with EU Directive 2011/65/EU amended by (EU) 2015/863 (RoHS3). These resistors feature a metal film deposited on a high dissipation ceramic former, adjusted by a helical cut, and protected by a lacquer coating. They are suitable for various applications requiring precise resistance values and stability.
Product Attributes
- Brand: TT Electronics
- Certifications: AEC-Q200 qualified, EU Directive 2011/65/EU amended by (EU) 2015/863 (RoHS3)
- Material: Metal film on ceramic former, plated steel cap terminations
- Color: Body protection and marking are resistant to industrial cleaning solvents
Technical Specifications
| Type | Power rating @70C (W) | Resistance range (ohms) | Limiting element voltage (V) | TCR (ppm/C) | Resistance tolerance (%) | Thermal impedance (C/W) | Zero-ohm jumper current rating (A) | Zero-ohm jumper maximum residual resistance (m) |
| WRM0102 | 0.2 | 1R0 1M0 | 200 | 15, 25, 50, 100 | 0.1, 0.25, 0.5, 1, 5 | 250 | 2 | 15 |
| WRM0204 | 0.25 | R22 5M1 | 250 | 5, 10, 15, 25, 50, 100 | 0.1, 0.25, 0.5, 1, 5 | 200 | 4 | 15 |
| WRM0207 | 0.4 | R22 4M7 | 250 | 15, 25, 50, 100 | 0.1, 0.25, 0.5, 1, 5 | 140 | 4 | 15 |
Performance Data
| Test | R/R (0102) | R/R (0204 & 0207) |
| Short time overload | 0.05% + R01 | 0.1% + R01 |
| Bending test | 0.15% + R05 | 0.3% + R05 |
| Resistance to soldering heat | 0.25% + R05 | 0.5% + R05 |
| Temperature rapid change | 0.25% + R05 | 0.5% + R05 |
| Endurance (load life) 1000 hrs | 0.15% + R05 | 0.3% + R05 |
| Endurance (load life) 8000 hrs | 0.3% + R05 | 0.6% + R05 |
| Endurance (load life) 225,000 hrs | 0.9% + R05 | 1.8% + R05 |
| Climatic sequence | 0.25% + R05 | 0.5% + R05 |
| Damp heat steady state | 0.25% + R05 | 0.5% + R05 |
| Current noise | <0.05V/V | <0.25V/V |
| Solderability | >95% coverage | >95% coverage |
| Voltage coefficient | 0 to -0.5ppm/V | |
| Voltage proof | No flashover or breakdown | |
Physical Data
| Type | L max (mm) | D max (mm) | D1 max (mm) | K min (mm) | L1 min (mm) | Wt. nom. (g) |
| WRM0102 | 2.3 | 1.35 | 1.3 | 0.3 | 1.1 | 0.01 |
| WRM0204 | 3.7 | 1.55 | 1.55 | 0.5 | 1.5 | 0.02 |
| WRM0207 | 6.1 | 2.4 | 2.4 | 0.5 | 2.9 | 0.08 |
2411181758_TT-Electronics-WRM0204C-160RFI_C20575599.pdf
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