Transistor destruction point

Thick-film resistor

destruction point

A.S.O.

Curve

B

D

C

S

E

5. Destruction capacity of the built-in emitter resistor

The built-in resistor is fabricated with polysilicone on the chip for the SAP08P/N and a thick-film resistor is

used for the SAP10P/N and SAP15P/N. The latter, the thick-film resistor, has weaker destruction point in

the Pc area (especially for large current flowing area) rather than that of the transistor chip itself. This is

subject to the area beyond Safe Operating Area (S.O.A).

However, under the evaluation like a short circuit test in which the current exceeds the guaranteed value, it

may cause the emitter resistor to be destroyed before the transistor itself is destroyed.

Consequently, the current value (or time) that operates the protection circuit is to be set at lower than that of

discrete device configurations. In the application of car audio amplifiers, the same manners as the above

need to be considered because the large current is flowed at low impedance.

In addition, once the transistor falls into thermal runaway due to a soldering failure to the external VR added

between diodes or other failure manners, as the worst case, there may cause a resin crack or smoke emissions

by flare up. Flame retardant molding resin is used, and the material of the product is conformed to the most

sever standard UL94V0. However it is recommended that the careful consideration be given to a protection

circuit, and the protection circuits should be provided appropriately in due course.

If the operating conditions are not to be matched to the ratings, it is also recommended that the E (Emitter

resistor) terminal should be opened and the external emitter resistor should be added to the S (Sensing)

terminal shown as below. (However this is not applicable to the SAP08P/N because a thin inner lead is used

for S terminal.)

External

emitter resistor

Output terminal