Can you please advise with following request?
- Thermal Conductivity Coefficient(W/m*K)
- Thermal(Heat) Capacity(J/kg*K)
Thanks in advance
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The following is the complete thermal model that we have for this device.
|TPS50601-SP Thermal Metric||Value||Unit|
|RθJA||Junction-to-ambient thermal resistance||24.6||°C/W|
|RθJC(top)||Junction-to-case (top) thermal resistance||7.0||°C/W|
|RθJC(bot)||Junction-to-case (bottom) thermal resistance||0.6||°C/W|
|RθJB||Junction-to-board thermal resistance||8.9||°C/W|
|ψJT||Junction-to-top characterization parameter||1.6||°C/W|
|ψJB||Junction-to-board characterization parameter||8.8||°C/W|
We need thermal conductivity value in W/mk for our simulation. So based on your comment above, if there is only resistance value in our hand, can we use below formula to obtain conductivity value from thermal resistance?
k= thermal conductivity
L= The thickness of package
A= Cross-section area of package
R,thetaJ= Junction-to-ambient thermal resistance.
If this formula is applicable, the conductivity value calculation will be as follows:
L=2,92 mm (max.) (CDFP3-F28, ceramic metal seal flatpack package)
A= 18,80 mm x 13,21 mm= 248,348 mm2
R,thetaJ= 24,6 °C/W = 24,6 K/W
k=2,92mm/(248,348mm2 * 24,6 K/W)= 4,77e-4 W/mmK= 0,48 W/mK (Conversion from mm to m)
Waiting your comments,
Thermal team has responded with the following reply:
"Thermal properties like thermal conductivity, heat capacity and density are for each material.
In a package you have die, ceramic header, lid, die attach, glass seal, wires. Each material will have its own properties. There isn’t one set of properties for a package.
What you provided are the thermal characterization parameter for a package according to JEDEC standard. They are used to estimate die temperature based on a particular system. If customer want to do thermal simulation, they can build the 2R model using Rjc and Rjb as junction to top and junction to board resistances, respectively.
2R model is only good for steady state simulation (not time dependent). If customer want to analyze transient, they need a different kind of thermal model (detailed thermal model). We can provide them detailed thermal model but we need to know what is the modeling tool; TI only has Icepak and Flotherm; we can only provide model in these two tool. If customer uses other tool, they must build their own model using our geometry and thermal properties.
BTW, using the R value to calculate k is fundamentally wrong. JEDEC standard JESD51-x explains this in detail."