Thermal Jumper Chip

TJC Series

General Note

TT Electronics reserves the right to make changes in product specification without notice or liability.

All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.

© TT Electronics plc

BI Technologies IRC Welwyn

www.ttelectronics.com/resistors

01.25

Thermal Performance Calculation

The thermal data are based on the thermal resistivity of aluminium nitride, which is 170 W/m°C.

Values for Thermal Resistance (TR) and Thermal Conductance (TC) are obtained as follows.

������������ =

������

������(������. ������)

where ������ is the thermal resistivity of AlN, 170W/m°C

������������ =

1

������������

Application Notes

TJC is designed to provide a thermally conductive pathway with electrical isolation. It

may be used as a thermal management solution for cooling PCB hotspot areas. A

typical application is pictured, in which a TO220 power device is cooled by linking it

to a pad which is heatsinked by a fixing which connects to the equipment chassis.

Electrical isolation from the chassis must be maintained, and direct connection to a

large copper groundplane is undesirable as it could lead to excessive radiated EMI.

To select the optimum size of TJC, begin by defining the range of terminal widths (W)

which best matches the pad or solder joint to be cooled. Then select the shortest

length dimension (L) within the constraints of capacitance and clearance require-

ments. The capacitance must be controlled for circuits operating at high frequency

and where coupling between the pad to be cooled and the heatsink pad is undesira-

ble. The clearance is important where high voltages can exist between the pads, and

this is given by dimension B. Since the surface of the insulated body of TJC is ceramic,

surface tracking is not considered an issue, so this dimension may be compared to

the air clearances required in the application design.

Ordering Procedure

Example: TJC1206LF-T3 (TJC in 1206 size, Pb-free)