TPK900L SOT-227 900W Non-Inductive High-Power Resistor

What is the TPK900L SOT-227 900W Non-Inductive High-Power Resistor?

The TPK900L is a single-element 900W thick-film power resistor in a compact SOT-227 package, engineered specifically for mounting on water-cooled chassis and other high-performance heat-dissipating systems. At just 12mm in terminal-side height, it is exceptionally low-profile for a resistor of its power rating, enabling installation in enclosures and mounting arrangements where vertical clearance is a primary constraint. The 900W continuous rating is achieved with the flange temperature held between −55°C and +25°C; above +25°C, power must be derated per the published derating curve, and the resistor should always be operated with an adequate cooling system in direct thermal contact with the flange.

The resistance range of 25Ω to 1kΩ follows the modified E24 series, and any resistance value within or beyond this range is available as a custom option. Standard tolerance is ±5%, with a ±1% option available for precision applications. The TCR of ±50ppm/°C across −55°C to +155°C ensures stable resistance through the full operating temperature range. At 10MHz, series inductance measures just 13.7nH and parallel capacitance 13.1pF — figures that reflect the non-inductive thick-film construction and confirm the TPK900L’s suitability for high-frequency pulse and RF-adjacent power circuit applications where parasitic reactance in the resistor would otherwise distort waveforms or reduce damping effectiveness.

High-voltage performance is central to the TPK900L’s design brief. The withstanding voltage of 10,000Vac for 60 seconds at 0.5mA is among the highest in the RARA power film range, and corona discharge inception is specified at 7,000V at 50kHz — a specification directly relevant to high-voltage pulse source design, where ionisation at insulation interfaces under repetitive high-dV/dt conditions is a critical failure mode. Insulation resistance between terminals and the bottom metal flange exceeds 1000MΩ, and the thermal resistance from resistive element to flange of 0.10°C/W ensures that the rated power is transferred efficiently into the cooling system. The published pulse operation data, derived from actual breaking tests on the 10Ω variant with a double safety factor applied, allows system designers to assess allowable peak pulse power for rectangular waveforms at a 0.01 duty cycle; pulse durability varies with resistance value and pulse source type, and evaluation on the target electronics is strongly recommended for pulse peak powers exceeding rated power.

Endurance performance is verified across a full suite of environmental tests. Load life at rated power over 1000 hours (90 minutes on, 30 minutes off, 25°C) limits resistance change to ±(1.0%+0.05Ω). Humidity testing at 70°C and 90–95% relative humidity for 1000 hours holds the same limit. Thermal cycling across −55°C to +125°C for 20 cycles also falls within ±(1.0%+0.05Ω). Short-time overload at 1.5× rated power for 5 seconds with a heatsink limits drift to ±(5.0%+0.05Ω), and vibration resistance is held within ±(0.25%+0.05Ω). Mounting is by two M4 screws in the standard two-terminal configuration; custom terminal arrangements are available from the factory.

Application note: The TPK900L is identified in the datasheet as a typical high-speed pulse power generator and water-cooling resistor, and its specifications are directly tailored to the requirements of advanced medical imaging and scientific equipment. In X-ray CT and MRI systems, high-voltage pulse generators produce repetitive high-voltage, high-current discharge pulses across load resistors to charge or shape the pulse waveform; the TPK900L’s 10kVac insulation, low inductance, and corona inception specification at 7kV/50kHz address the specific dielectric and electromagnetic demands of these circuits. In EUV laser and similar pulsed-power sources, the resistor serves as a precision charge/discharge or voltage-divider element across the pulse-forming network, where both high-voltage standoff and waveform fidelity under repetitive pulse loading are essential. The water-cooled chassis format suits the continuous high-power duty cycles of these installations, and the compact SOT-227 body allows multiple units to be arranged in series or parallel arrays on a single cold plate to scale voltage, power, or resistance as required.

Model: TPK900L
Resistor type: Power film
Description: Chassis mounted
Power Rating: 900W
Resistance (Ω): 25~1k
Tolerance (%): ±5
TCR (ppm/C): 50

Model: TPX600L
Resistor type: Power film
Description: Chassis mounted
Power Rating: 600W
Resistance (Ω): 10~1k
Tolerance (%): ±5
TCR (ppm/C): 50

Model: TPK600, TPK900
Resistor type: Power film
Description: Chassis mounted
Power Rating: 600W, 900W
Resistance (Ω): 10~1.6k
Tolerance (%): ±5
TCR (ppm/C): 50

Model: TPU
Resistor type: Power film
Description: Chassis mounted
Power Rating: 300W, 600W, 800W
Resistance (Ω): 4.7~500M
Tolerance (%): ±1, ±2, ±5, ±10
TCR (ppm/C): 50-250.

Model: TPM150~600
Resistor type: Power film
Description: Chassis mounted
Power Rating: 150W~600W
Resistance (Ω): 0.1~1M
Tolerance (%): ±5
TCR (ppm/C): 100