DS90CR288A: θjc

Hi Anthony,

Thank you for reply.

Does your answer mean "Package Derating" ?

The Package Derating section is expressed as follows　
12.4 mW/°C above +25°C

The junction temperature is obtained from the following equation

Tj = Ta + θja × P [W]

"Maximum Package Power Dissipation @ +25°C" = 1.61W represents the power that the IC can dissipate at Ta = 25°C

1.61[W]=(Tj(max)-Ta)/θja
=(150-25)/θja
　
θja = 125/1.61 = 77.63 [°C/W].

The reciprocal of Package Derating =12.4 mW/°C is
1/12.4[mW]=80.64[°C/W].
which is not the same as the above value, but is probably close to the value obtained from Maximum Package Power Dissipation.

Since θjc is usually smaller than θja, the reciprocal of Package Derating =12.4 mW/°C is also θja in the calculation, so I think that it would not be θjc.

Could you check again with the database, etc. whether there is information on θjc?

Best Regards,

ttd

Hi Anthony,

Thank you for your reply.

I got theta JC value is 20.7 C/W.

By the way, do you have theta JA(θja) value?

Best Regards,

ttd

Hi ttd,

Give me a couple days to see if we have the theta JA value.

Best regards,

Anthony