AN533

Through-hole packages

9/22

Table 1 shows the thermal resistance for different TO-220AB insulators and for a given

pressure (F = 30 N).

1.4

Insulated components

Most of the thyristors and TRIACs manufactured by STMicroelectronics are available in

insulated and non-insulated packages. For insulated packages, insulation can be achieved

in two different ways:

●

ceramic between the die pad and the heatsink of the component (TO-220AB / TOP3 /

RD91 packages)

●

resin used for encapsulation (ISOWATT220AB / TO-220FPAB packages)

All insulated packages delivered by STMicroelectronics are in accordance with UL1557

recognition applicable for "electrically isolated semiconductors". The added material

increases the thermal resistance between the junction and the case, but the total thermal

external insulating material. In addition, it simplifies assembly and reduces the cost.

1.5

Handling and mounting techniques

The use of inappropriate techniques or unsuitable tools during handling and mounting can

affect the long term reliability of the device, or even damage it.

1.5.1

Bending and cutting leads

Lead bending must be done carefully. The lead must be firmly held between the plastic

package and the bending point during lead operation. If the package / lead interface is

strained, the resistance to humidity is impaired and in addition mechanical stress is inflicted

on the die. This damage can affect the long term reliability of the devices.

Table 1.

Contact grease

Mica + grease

thickness = 80 µm

Mica dry

thickness = 80 µm

Silicone insulator

0.5

1.7

4

2.6

Table 2.

BTA16-600C

(insulated version)

BTB16-600C

(non-insulated version)

2.1 device

1.2 device

+ 0.5 grease

+ 1.7 mica + grease

= 2.6 total

= 2.9 total