The TPX600L is a 600W thick-film power resistor housed in an SOT-227 package, distinguished within the RARA power film range by its exceptionally compact body dimensions — at just 10mm thick, it is the smallest SOT-227 600W resistor in the series, enabling installation in mounting spaces too restricted for conventional high-power resistor packages. The rated 600W continuous dissipation is achieved when the case temperature is maintained between −55°C and +80°C via attachment to an appropriate heatsink; above +80°C, power must be derated according to the published derating curve. In free-air without a heatsink, the maximum safe operating power is 5W at room temperature.
The resistance range of 10Ω to 1kΩ follows the E24 series with the addition of the 2.5 and 5.0 values, and extended resistance options are available on request. Standard tolerance is ±5%, with an optional ±1% tolerance available for applications requiring tighter resistance accuracy. The TCR of ±50ppm/°C is maintained across the full −55°C to +155°C operating temperature range, ensuring stable resistance under the thermal cycling conditions typical of power electronics duty. The thick-film non-inductive construction holds series reactance to a minimum, making the TPX600L suitable for high-frequency and fast-switching circuit environments where inductive parasitic effects in the resistor would degrade snubber, gate drive, or filter performance.
High-voltage isolation is a notable feature of the TPX600L. The insulation voltage rating of 8000Vac for 60 seconds at 0.5mA confirms suitability for high-voltage pulse circuits, power converters operating from elevated DC buses, and divider networks across high-voltage rails. Insulation resistance between the internal conductors and the external flange exceeds 1000MΩ, and the resistor body and metal flange are electrically isolated from one another, eliminating the need for an insulating sheet between the resistor and heatsink during mounting. The low thermal resistance of 0.10°C/W from element to flange ensures efficient heat transfer to the mounting surface, and the use of heat-conducting grease is recommended to minimise interface thermal resistance.
Reliability is validated across a comprehensive set of endurance conditions. Load life testing at rated power over 1000 hours (90 minutes on, 30 minutes off, 25°C) holds resistance change to within ±1.00%. Thermal cycling across −55°C to +155°C for five cycles also limits drift to ±1.00%. Moisture tolerance testing at 85°C and 85% relative humidity for 1000 hours, short-time overload at 2.5× rated power for 5 seconds, and vibration testing per JIS C 60068-2-6 all hold resistance change within ±0.25%. The UL94-V0 rated resin case adds flame-retardant integrity appropriate for enclosed industrial and power electronics assemblies.
Application note: The SOT-227 package format of the TPX600L is widely used in power electronics designs where a high-power resistor must be co-located with IGBTs, MOSFETs, or diode modules that share the same heatsink or cold plate. In high-voltage pulse generating circuits and pulse power sources, the combination of 8kVac insulation, non-inductive construction, and 2.5× short-time overload capability makes the TPX600L well suited to absorbing the transient energy of pulse loads without degradation. As a snubber resistor across switching devices, the non-inductive thick-film element damps voltage transients at the switching node without introducing the parasitic inductance that would reduce snubber effectiveness. In voltage divider, filtering, and breeder resistor applications across high-voltage power supplies, the high insulation rating and stable TCR ensure both electrical safety and measurement accuracy. The compact 10mm profile further benefits installations where component height above the heatsink is constrained by enclosure lids, bus bars, or adjacent components.
