AS355R025

Overview

The AS355R025 is an NTC thermistor inrush current limiter manufactured by Vishay Ametherm. It features a nominal resistance of 5 Ohms at 25°C with a tolerance of ±25%. The component supports a maximum steady-state current of 25 A and a peak inrush current capacity of 35 A. It has a dissipation factor of 78.2 mW/°C and can withstand a recommended energy of 600 Joules, with an actual energy failure threshold of 1200 Joules. The device is designed for compact power control applications.

Feature Summary

• Provides effective limitation of high inrush currents during power-up sequences to protect downstream components.
• Features a robust construction capable of handling significant thermal energy pulses without failure.
• Designed for easy mounting within power control boxes using standard screw terminals.

Applications

• Protection of transformers against inrush current damage
• Power supply input stage protection
• Motor drive circuit initialization

Procurement Notes

Verify the specific ordering suffix and package configuration against the official Vishay datasheet to ensure compatibility with your PCB layout or terminal block requirements. Confirm that the 25 A steady-state current rating meets the continuous load demands of your application. Check for any recent updates to the RoHS compliance status or manufacturing location before finalizing procurement orders.

Selection Notes

Select this component when a 5 Ohm initial resistance is required to limit inrush current to approximately 35 A. Ensure the application's steady-state operating current does not exceed 25 A to prevent overheating. Consider the thermal environment, as the dissipation factor influences the self-heating characteristics under continuous load conditions.

Part Context

This part belongs to the AS35 series of inrush current limiters from Vishay Ametherm. These devices are specifically engineered for circuit protection in power electronics. The series offers various resistance values and current ratings to suit different power levels, providing a standardized solution for managing startup transients in industrial and commercial equipment.

Replacement Considerations

Direct substitutes must match the 5 Ohm resistance, 25 A current rating, and similar physical dimensions. Verify that alternative NTC thermistors offer comparable energy absorption capabilities (minimum 600 J) and identical mounting styles to ensure mechanical and electrical interchangeability.