LM2904V: max allowable power dissipation

Hisao-san,

Maximum power dissipation depends on many factors. Data sheet section 7.1 Absolute Maximum Ratings states that absolute maximum junction temperature is 150C. The power dissipation to get to 150 C depends on ambient and board temperature, air flows and other factors.

Data sheet Section 7.4 Thermal Information provides thermal resistances that are a good starting point. Application  boards results will vary from the standard thermal test board results.

I did not understand the second question/request, can you restate with more detail?

Hi Ron,

Thank you for your answer.

Assuming theta j-a is 171.7 degree/W and Ta is 60 degree, Pd can be estimated as below.

60 + Pd * 171.7 < 150

Pd < 524mW

When Vs is 24V, output current or Io can be up to 45mA (not included Iq).

Is this estimation correct? Is there any max allowable power for TSSOP package?

Please let me know if my question is unclear.

Regards,

Hisao Uchikoshi

Hisao-san,

Your calculation is correct. 45mA is a lot of output current for this device. Does this happen in normal operating or in fault condition?

The power heats the die and the heat of the die impacts the package. The PW package is rated for the temperature range of LM2904V.

Here is the power used in the LM2904V (total sum for all)

ICC * VCC

Outputs sourcing current (VCC-VOUT) * IOUT

Outputs sinking current (VOUT) * IOUT

Hi Ron,

This is a replacement opportunity and comparing the spec. This is not the actual usage model. The existing opamp defines the abs power dissipation which is for package(see note). So do you have any data?

Regards,

Hisao Uchikoshi