5D-11 Negative Temperature Coefficient Thermistor

5D-11 Negative Temperature Coefficient Thermistor serves as a high-performance inrush current limiter, protecting sensitive electronic components from damaging power surges during startup. This NTC thermistor exhibits a high resistance at room temperature, which effectively restricts the initial flow of current when you first power on a device. Consequently, as the device operates and the component heats up, its resistance drops significantly to ensure efficient power delivery with minimal loss. Furthermore, the 5D-11 model features a compact disc design that integrates easily into power supply circuits and motor controllers. Therefore, you can rely on this robust component to extend the lifespan of your electronics by preventing blown fuses and semiconductor failure.

Key Features:

• Reliable Surge Protection: This device effectively suppresses inrush current, safeguarding electrolytic capacitors and bridge rectifiers from peak current stress.
• High Thermal Stability: The high-quality ceramic material ensures consistent performance even after repeated heating and cooling cycles.
• Compact Form Factor: The 11 mm disc diameter allows for high-density mounting on crowded printed circuit boards without sacrificing thermal dissipation.
• Fast Response Time: The NTC material reacts quickly to temperature changes, transitioning from high to low resistance states within seconds of power application.
• Cost-Effective Solution: It provides a simple yet highly effective alternative to complex active soft-start circuits in low-to-medium power applications.

Technical Specifications:

• Resistance at 25°C (R₂₅): 5 Ω ±20%
• Maximum Steady State Current: 3.5 A to 4 A
• Approximate Resistance at Max Current: 0.15 Ω
• Thermal Dissipation Constant: ≈ 13 mW/°C
• Thermal Time Constant: ≤ 45 seconds
• Operating Temperature Range: −55°C to +155°C

Mechanical Specifications:

• Component Type: Radial Leaded Power NTC Thermistor
• Coating Material: Flame-retardant Silicone or Phenolic Resin (UL 94 V-0)
• Lead Material: Tinned Copper Wire
• Durability: Withstands high mechanical vibration and thermal shock common in industrial environments.

Dimensions:

• Disc Diameter (D): ≈ 11 mm
• Disc Thickness (T): ≈ 5.0 mm
• Lead Pitch (F): ≈ 7.5 mm
• Lead Diameter: ≈ 0.8 mm
• Lead Length: ≥ 25 mm

Pinout and Wiring:

• Pin 1 (Input): Connect this lead in series with the AC or DC live/positive line.
• Pin 2 (Output): Connect this lead to the input of the bridge rectifier or the main filter capacitor.
• Wiring Note: However, you must provide adequate clearance around the thermistor as it generates significant heat during steady-state operation. Do not place heat-sensitive components directly adjacent to the 5D-11.

Datasheet Reference:

• Download 5D-11 Power NTC Thermistor Datasheet

Commonly Used in:

• Switch Mode Power Supplies (SMPS): Protecting the input stage from the high charging current of bulk capacitors.
• LED Drivers: Preventing flickering and component damage during the initial power-up phase.
• Uninterruptible Power Supplies (UPS): Managing current spikes when switching between battery and mains power.

Applications:

• Soft Start Systems: Implementing basic soft-start functionality for AC motors and transformers.
• Consumer Electronics: Shielding televisions, monitors, and audio amplifiers from power-on surges.
• Industrial Controllers: Limiting current in automated systems and heating elements.

Equivalent Models:

• SCK-054: A functionally identical model from Thinking Electronic with a 5 Ω resistance and similar current rating.
• NTC 5D-11 (Generic): Various manufacturers produce the 5D-11 footprint with matching electrical characteristics.
• B57236S0509M000 (TDK/EPCOS): A high-quality alternative that provides comparable inrush current suppression.

Package Includes:

• 1 x 5D-11 Negative Temperature Coefficient (NTC) Thermistor