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Original question:

SN74HCT541: Thermal Information

SN74HCT541: Change of data sheet specifications (thermal information)

Daisuke Higa
Genius 3805 points
Part Number: SN74HCT541

Hi support team.

I asked from my customer about the thermal information of SN74HCT541.

My customers seem to be having to reconsider their past thermal designs.

The thermal resistance value of each package has increased significantly from Rev.E to Rev.D.

I found information about NS packages in past posts.

https://e2e.ti.com/support/logic-group/logic/f/logic-forum/889944/sn74hct541-thermal-information

The thermal resistance values mentioned in the comments on above post were also significantly lower than the current datasheet (Rev.E) values.

Could you tell me why the big difference occurred?

Best regards,

Higa

  • +1
    TI__Expert 8221 points

    Hi Daisuke,

    During a routine datasheet update, this device’s thermal values (RΘJA, RΘJC(top), RΘJC(bot), RΘJB, ψJT, ψJB), as described in the Thermal Information Table, were updated to be more accurate.  TI now uses an improved thermal model to calculate thermal impedance values, and these new thermal values may differ slightly from the existing values in the datasheet.  The materials used, manufacturing process, and device core have not changed, so electrical performance will remain the same.  Only the thermal characteristics of the datasheet have been updated.

    Regards,

    Owen

  • 0 in reply to Owen Westfall
    Genius 3805 points

    Hi Owen-san

    Thank you for your prompt reply.

    I understand.

    Thanks

    Regards,

    Higa