TLV733P: Ambient Temperature

Hi,

Yes, the maximum recommended junction temperature (Tj,max) for the TLV733P is 125 C. Whether it is safe to use this LDO at 105 C will depend on the application's input voltage, output voltage and output current. This determines the power dissipated in the pass transistor:

Pd = (Vin - Vout) * Iout

For an ambient temperature of 105 C (Ta), the required junction to ambient thermal resistance (Rja) can be calculated as:

Rja = (Tj,max - Ta)/Pd

This will then need to be compared to the datasheet specification provided in the Thermal Information table:

This is derived using a model of the JEDEC High-K Thermal Test Board. The specifications of this board can be accessed after registering an account with JEDEC for free:

https://www.jedec.org/user/register

https://www.jedec.org/system/files/docs/jesd51-7.PDF

Due to the large thermal resistances of both the SOT-23 and X2SON package, it is highly recommended to design a thermally optimized layout that maximizes copper area connected to the LDO on the top layer, internal layers, and bottom layer. Vias around the LDO can spread the generated heat to these other layers. This will reduce Rja and therefore increase the maximum ambient temperature. With these techniques, it is possible to reduce Rja by roughly 40% to 50% for the SOT-23 package. The X2SON package, due to its smaller size, sees much less improvement at roughly 10% to 15%.

Thanks,

Gerard