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DAC8760: Thermal resistance of DAC8760

MESH
Intellectual 880 points
Part Number: DAC8760

Hello,

I considering analog output circuit board that uses DAC8760.

I would like to know which of the following conditions is the thermal resistance value of junction to ambient in section 7.4 of the DAC8760 data sheet.

Condition 1: The condition that the thermal pad on the bottom of the package is connected to the copper plane of the board.

Condition 2: The condition that the thermal pad on the bottom of the package is not connected to the copper plane of the board.

If it is a characteristic of junction to ambient thermal resistance value under the condition that thermal pad is connected to the copper plane, please tell me the thermal resistance under the condition that it is not connected.
(If the characteristic value of thermal resistance at this condition is clarified)

The usage conditions of DAC8760 are shown below as reference.

- The DAC8760 will use only voltage output function.
   (Does not use current output function of DAC8760)

- The bottom of thermal pad does not connect to AVSS copper plane.
   (The AVSS pin (1pin of HTTSSOP package) is conncted to negative supply voltage)

- Volatge output pin of DAC8760 is connected to input pin of external opeamp circuit.
   (Connects to high impeedance input)

Regards,
MESH

  • +1
    TI__Guru* 97465 points

    MESH,


    We don't have that kind of information at hand. The calculation for the thermal resistances comes from a combination of information such as the lead frame, mold compound, die attach, die structure, and the exposed pad. The datasheet has numbers for these thermal resistances calculated from these parameters using the JEDEC standard assumptions about the use of the device and connections to the board.

    There may be some information about our thermal metrics in the following link about how these parameters are used:
    https://www.ti.com/lit/spra953

    But the following may have a little more information about how the thermal metrics change with different layout and connections to the device.
    https://www.ti.com/lit/snva183
    https://www.ti.com/lit/snva419


    Joseph Wu

  • 0 in reply to Joseph Wu
    Intellectual 880 points

    Hi Joseph,

    Thank you for your reply.

    I understand the situation of this thermal resistance value.

    Thank you for the information in the related materials.

    Regards,

    MESH