5D-13 Negative Temperature Coefficient Thermistor

5D-13 Negative Temperature Coefficient Thermistor serves as a high-reliability power NTC component specifically designed to suppress inrush current in electronic circuits. This power-type thermistor effectively limits surge currents during the initial power-on phase by offering high resistance at ambient temperatures. Consequently, as the device heats up due to current flow, its resistance drops significantly, allowing the circuit to operate with minimal power loss. Designers utilize the 5D-13 series to protect sensitive components like bridge rectifiers and electrolytic capacitors from high-energy spikes. Furthermore, this robust component enhances the overall lifespan of power supplies by reducing thermal and electrical stress on downstream semiconductors. Therefore, you should integrate this 13mm diameter thermistor into any AC-to-DC conversion system where reliable startup protection is a primary requirement.

Key Features:

• High Inrush Current Suppression: The device effectively clamps initial current surges, protecting circuit fuses and preventing nuisance tripping.
• Excellent Thermal Stability: It maintains consistent performance across a wide operating temperature range, ensuring reliability in industrial environments.
• Compact Radial Design: The 13 mm disk size offers a perfect balance between high power handling and space-saving PCB mounting.
• High Material Constant: Features a high B-value, which provides a sharp change in resistance for efficient circuit transition.
• Durable Coating: The silicone or phenolic resin coating provides environmental protection and high dielectric strength.

Technical Specifications:

• Resistance at 25°C (R₂₅): 5 Ω ±20%
• Maximum Steady State Current: 4.0 A
• Approximate Resistance at Max Current: 0.125 Ω
• Thermal Dissipation Constant: ≈ 16 mW/°C
• Thermal Time Constant: ≤ 60 Seconds
• B-Value (±10%): 2800 K to 3000 K
• Operating Temperature Range: −55°C to +200°C

Mechanical Specifications:

• Lead Style: Radial Lead (Straight or Kinked)
• Coating Material: Flame-Retardant Epoxy Resin
• Lead Material: Tinned Copper
• Solderability: Meets MIL-STD-202 Method 208 standards

Dimensions:

• Disk Diameter (D): ≈ 13.0 mm to 14.5 mm
• Thickness (T): ≈ 5.0 mm maximum
• Lead Pitch (F): 7.5 mm ±1.0 mm
• Lead Diameter: 0.8 mm ±0.1 mm
• Lead Length: ≥ 25.0 mm

Pinout and Wiring:

• Polarity: This component is non-polarized; however, you must wire it in series with the AC or DC power line.
• Placement: Always position the thermistor before the reservoir capacitor and after the fuse to ensure the fuse remains intact during surge.
• Thermal Clearance: Maintain adequate spacing from heat-sensitive components, as the thermistor surface reaches high temperatures during steady-state operation.

Datasheet Reference:

• Download MF72 (5D-13) NTC Thermistor Datasheet

Commonly Used in:

• Switching Mode Power Supplies (SMPS): Limiting the charging current of large filter capacitors.
• AC Motors: Soft-starting small electric motors to prevent mechanical and electrical stress.
• Uninterruptible Power Supplies (UPS): Protecting the inverter and battery charging circuits.

Applications:

• Consumer Electronics: Standard protection in televisions, audio amplifiers, and monitors.
• LED Drivers: Managing the high initial capacitive load seen in modern high-wattage LED systems.
• Industrial Controls: Ensuring stable power-up sequences for PLC systems and sensor arrays.

Equivalent Models:

• MF72-5D13: The standard industrial part number for this 5-ohm, 13mm NTC thermistor.
• SCK-054: A functional equivalent from many manufacturers offering the same 4A steady-state current rating.
• NTC 5D-11: A slightly smaller alternative, however, it provides lower power dissipation compared to the 13mm version.

Package Includes:

• 1 x 5D-13 Negative Temperature Coefficient (NTC) Thermistor