TL432B: TL432B Maximum Power Rating

Wei-Hao Chen (TW-FAE)

Part Number: TL432B

Hi Support Team Champs:

My customer is having the question on what is the maximum power rating for TL432BQDBZRQ1? Suppose the Pd = Vka * Ika? Is this the valid way to calculate the maximum power this device can handle?

Thank you.

Best Regards,

Wei-Hao

over 7 years ago

0 kai klaas69 over 7 years ago

Guru 140200 points

Hi Wei,

you can calculate by yourself: The DBZ package has a thermal resistance of 206°C/W. So, with a heat dissipation of 0.5W the junction will heat up 103°C over ambient temperature. If the ambient temperature is 40°C, the junction will heat up to 143°C. Such a high junction temperature cannot be recommended. It should stay well below 125°C. A heat dissipation of 300mW maximum would be a good choice with an ambient temerature of 40°C maximum.

The heat dissipation is calculated by taking the voltage drop across the TL432B times the current flowing through the TL432B. The voltage drop is the voltage between cathode and anode.

Kai

0 Marcoo Z over 7 years ago

TI__Mastermind 19580 points

Hi Wei-Hao,

Kai did a good summary of how to estimate Tj with R(theta JA).
Here is an article from TI that goes into more detail on this.
www.ti.com/.../spra953c.pdf

Keep in mind that using R (theta JA) can sometimes over estimate the Tj just because the heat might dissipate through the board or other system parameters.

-Marcoo

0 Wei-Hao Chen (TW-FAE) over 7 years ago in reply to kai klaas69

TI__Expert 3260 points

Kai,

Thank you for your clear explanation. It really helps.

Best Regards,
Wei-Hao

0 Wei-Hao Chen (TW-FAE) over 7 years ago in reply to Marcoo Z

TI__Expert 3260 points

Hi Marcoo,

Got it thanks!

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TL432B: TL432B Maximum Power Rating