Conducts heat. Blocks electricity. A new approach to heat dissipation.

As electronic devices become smaller and more powerful, the problem of "not being able to release heat from high-power heat sources" is becoming increasingly serious.

Conventional heat countermeasures include:
-Added heat sink
・Expansion of copper foil on the board
-Addition of multiple thermal vias
These were mainstream methods, but they had a fundamental limitation: "Heat cannot be dissipated in places where there is no electrical connection."

What are Bourns thermal jumper chips?

Thermal Jumper = abbreviated as "TJ".

The TJ series is an SMD chip that uses an electrically insulated AlN (aluminum nitride) substrate.
Simply place it between the heat source and the heat dissipation path and it will quickly transfer heat without conducting electricity.

Conventional (without TJ)

High heat source: 120℃
→ Heat accumulates in the surrounding area, affecting the lifespan of parts

When using TJ

Temperature reduced to approximately 80°C
→ Heat is efficiently bypassed to GND/copper foil.

Why is TJ so efficient? (Mechanism)

As shown in the diagram on the left, TJ moves heat from the heat source to the thermal jumper and then to the heat sink (copper foil) while maintaining electrical insulation.

■ Features of the TJ's internal structure
- Aluminum nitride substrate (170W/m·K): Thermal conductivity is more than half that of copper and more than 100 times that of resin.
- Dielectric strength voltage (1.5 to 5 kVac): Can be installed in places with large potential differences.
- Low capacitance (0.07 to 0.26 pF): No adverse effects even on RF/high-speed circuits.
・SMD size (0603〜2512)

Main features

• High thermal conductivity (AlN 170W/m·K): Bypasses heat in the shortest distance, dramatically reducing hot spots.
• Complete electrical isolation: Can be safely placed around SW nodes, MOSFETs, and PAs with different potentials.
• Ultra-low capacitance (0.07–0.26 pF): Does not distort waveforms even in RF, 5G, and high-speed digital applications.
• Available in multiple sizes: 0508 / 0603 / 0612 / 1206 / 1225 / 2512. Select the optimal size for your application.

Target application

• LED lighting (measures to prevent heat concentration on the driver IC): Bypasses only heat from the driver IC to the rear spreader, contributing to maintaining luminous flux.
• Power electronics (MOSFET / Regulator): Even in places where there is a potential difference, heat can be safely dissipated.
• Automotive ECU: Diffuses hot spots across the entire board, improving reliability.
• Communications equipment/5G (PA/RF): Low capacitance suppresses temperature peaks while maintaining RF characteristics.
• Battery pack/BMS: Optimized thermal paths in areas where heat tends to accumulate, such as the cell balancing circuit.

Technical specifications (typical values)

Design Guide

■ Recommended layout
- Wide heat dissipation area (GND/copper foil)
・Via array (thermal via) placed near TJ
・Ensures insulation distance and can be used between pads with potential differences

■ Evaluation points
・ΔT comparison with and without TJ (IR camera)
・Optimization of heat dissipation area and number of vias
・For RF applications, check the effect of capacitance (pF) (usually no problem)
・The "last resort" for projects where circuit changes are not possible

Related Information

If you would like to view the product page or data sheet, please see below.

• Thermal Jumper Chip Product Page
• Thermal Jumper Chip Product Datasheet

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