5D-15 Negative Temperature Coefficient Thermistor

5D-15 Negative Temperature Coefficient Thermistor serves as a high-performance inrush current limiter, protecting electronic circuits from sudden 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 component heats up due to the passing current, its resistance drops significantly to a negligible level, allowing the circuit to operate with minimal power loss. Utilizing a specialized metal oxide ceramic material, the 5D-15 ensures long-term stability and rapid response times. Furthermore, this compact radial-leaded device offers a cost-effective solution for safeguarding sensitive power supplies and motor controllers. Therefore, integrating this thermistor into your design provides a reliable hardware-level defense against damaging electrical transients.

Key Features:

• High Inrush Current Suppression: The device effectively absorbs peak current surges during the initial power-up phase to prevent fuse blowing or component damage.
• Wide Operating Range: This thermistor functions reliably across a broad temperature spectrum, making it suitable for diverse industrial and consumer environments.
• Fast Thermal Response: The high-quality ceramic body reacts quickly to temperature changes, ensuring a smooth transition from high to low resistance.
• Excellent Mechanical Strength: A robust resin coating protects the internal ceramic element from moisture, oxidation, and physical vibration.
• Compact Radial Design: The small 15 mm disk size allows for easy integration into high-density printed circuit board (PCB) layouts.

Technical Specifications:

• Zero Power Resistance (R₂₅): 5 Ω ±20% (measured at 25°C)
• Max. Steady State Current: 6 A
• Approximate Resistance at Max Current: 0.125 Ω
• Thermal Dissipation Constant (δ): ≈ 20 mW/°C
• Thermal Time Constant (τ): ≈ 76 Seconds
• Operating Temperature: −55°C to +200°C
• Material Constant (B-Value): ≈ 3000 K

Mechanical Specifications:

• Body Coating: Silicone or Phenolic Resin (Black or Green)
• Lead Material: Tinned Copper Wire
• Lead Style: Radial-leaded (Straight or Kinked)
• Flame Retardancy: Meets UL 94 V-0 standards

Dimensions:

• Disk Diameter (D): ≈ 15.0 mm
• Thickness (T): ≤ 6.0 mm
• Lead Pitch (F): ≈ 7.5 mm (±1.0 mm)
• Lead Diameter: ≈ 0.8 mm
• Lead Length: ≥ 25.0 mm

Pinout and Wiring:

• Connection Type: Non-polarized two-terminal device.
• Series Placement: Install the thermistor in series with the AC or DC power line (typically on the “Hot” or “Positive” side) before the bulk filter capacitors.
• Thermal Management: Maintain adequate spacing from other heat-sensitive components, however, ensure the leads are long enough to dissipate heat away from the PCB.
• Wiring Note: Avoid using this device in parallel, as the current will not share equally between units due to their negative temperature coefficient.

Datasheet Reference:

• Download 5D-15 NTC Thermistor Datasheet

Commonly Used in:

• Switch Mode Power Supplies (SMPS): Protecting bridge rectifiers and capacitors from initial charging currents.
• Uninterruptible Power Supplies (UPS): managing the high power requirements during battery-to-inverter transitions.
• LED Driver Circuits: Preventing high-frequency driver damage during the startup cycle.

Applications:

• AC/DC Adapters: Providing soft-start capabilities for laptops, monitors, and various consumer electronics.
• Electric Motor Starters: Limiting the peak current when starting induction or DC motors.
• Vacuum Cleaners and Hairdryers: Reducing the electrical stress on internal switches and heating elements.
• Inverters: Protecting the MOSFETs or IGBTs from high-voltage input transients.

Equivalent Models:

• SCK-056: A common alternative with a 5 Ω cold resistance and similar current handling capacity.
• NTC 5D-15: Generic manufacturer part number that adheres to the same physical and electrical standards.
• TDK/Epcos B57237S0509M000: A premium equivalent that offers high reliability for industrial-grade power protection.

Package Includes:

• 1 x 5D-15 Negative Temperature Coefficient (NTC) Thermistor