TNP-25 / TNP-45 Series SMD Surge Protection Power Film Resistors

What are the TNP-25 / TNP-45 Series SMD Surge Protection Power Film Resistors?

The TNP-25 and TNP-45 are surface-mount power film resistors engineered for applications that demand compact, high-power-density components capable of withstanding surge and pulse overloads without permanent resistance shift. The TNP-25 is rated at 25W continuous and the TNP-45 at 45W, both referenced to a backing metal temperature of −55°C to +25°C. Both models share the same resistance range of 0.1Ω to 51kΩ and are available in ±1% tolerance only, reflecting the precision-oriented markets these devices serve. Their surface-mount form factor and low profile make them well suited to automated PCB assembly processes and space-constrained board layouts where through-hole power resistors would be impractical.

A key characteristic of both models is their short-time overload capability of 2.0 times rated power for 5 seconds at 25°C — 50W for both the TNP-25 and TNP-45 under these conditions. This surge tolerance is essential in circuits where inrush currents, capacitor charging transients or fault conditions momentarily drive power well above steady-state levels. The temperature coefficient of resistance is specified at ±100ppm/°C maximum across the full resistance range, ensuring that resistance remains stable over the operating temperature span of −55°C to +155°C. Load life stability is ±[1.0%+0.05Ω] after 1000 hours of 90-minutes-on/30-minutes-off cycling, and humidity endurance is equivalent under 40°C, 90–95% RH conditions.

The film construction delivers excellent RF characteristics, maintaining consistent impedance behaviour at high frequencies where wirewound or thick-film alternatives would introduce inductive or parasitic effects. This makes the TNP-25 and TNP-45 particularly effective in high-speed pulse circuits, switching converters, and RF-adjacent power electronics where the resistor's frequency response directly affects circuit performance. Temperature cycle endurance across −55°C to +155°C for five cycles yields a resistance change no greater than ±[0.25%+0.05Ω], and vibration performance is qualified to IEC 60068-2-6. Soldering heat stability is ±[0.1%+0.05Ω] at 350°C for 3 seconds, confirming compatibility with standard reflow and hand-soldering processes.

Dielectric withstanding voltage is rated at AC 1500V for 1 minute with a maximum leakage current of 1mA, and insulation resistance is guaranteed at 1000MΩ minimum. Standard resistance values follow a series covering common preferred values from 1.0Ω through 9.1Ω and extending to 51kΩ, with tape-and-reel packaging available for volume production pick-and-place assembly.

Model: TNP25, TNP45
Resistor type: Power film
Description: SMD surge protection
Power Rating: 25W, 45W
Resistance (Ω): 0.1~51k
Tolerance (%): ±1
TCR (ppm/C): 100

Model: RTS-01
Resistor type: Power film
Description: Heatsinkable thick film
Power Rating: 100W
Resistance (Ω): 0.1~1M
Tolerance (%): ±5, ±10
TCR (ppm/C): 100

Model: RTS-02
Resistor type: Power film
Description: Heatsinkable thick film
Power Rating: 300W, 600W
Resistance (Ω): 0.1~1M
Tolerance (%): ±5, ±10
TCR (ppm/C): 100.

Model: TNP10/20S/50U
Resistor type: Power film
Description: Power thin film
Power Rating: 20W, 35W, 50W
Resistance (Ω): 0.02~510k
Tolerance (%): ±1, ±5
TCR (ppm/C): 50, 100, 250

Model: TNP50S, TNP100S
Resistor type: Power film
Description: Power thin film, TO227
Power Rating: 50W, 100W
Resistance (Ω): 0.02~510k
Tolerance (%): ±1, ±5
TCR (ppm/C): 50, 100, 250.