TPS715-Q1: TPS71501QDCKRQ1

PONNOJU NAGASHIRISHA

Part Number: TPS715-Q1
Other Parts Discussed in Thread: TPS7B81-Q1

Our design requirement- Input voltage - 24v, output voltage - 5V

For the calculation of Power dissipation, Pd=(Vin-Vout)*Io

Where output current (Io) we considered 50mA as per datasheet. Value we got as more than 900mA which is not at all meeting the required value as per datasheet.

Please provide me as per my requirement can i use this part of LDO or not ?

over 2 years ago

0 Erin Thibeault over 2 years ago

TI__Expert 6570 points

Hi,

I calculated power dissipation for 24V input and 5V output at 50mA:

Pd = (Vin - Vout) * Iout = (24-5) * 0.05 = 0.95W

TPS715-Q1 R_ΘJA: 195.7°C/W (new chip)

195.7°C/W * 0.95W = 185.92°C

TPS715-Q1 temperature will be ambient temperature + 185.92°C under these conditions. The maximum operating temperature for TPS715-Q1 is 125°C. An LDO in a different package, that can more effectively dissipate heat might be better in this application.

BR,

Erin

0 PONNOJU NAGASHIRISHA over 2 years ago in reply to Erin Thibeault

Prodigy 40 points

Thanks for the message.

Could you please support to share the different package which will be suitable as you mentioned for our requirements.

Regards,

0 Erin Thibeault over 2 years ago in reply to PONNOJU NAGASHIRISHA

TI__Expert 6570 points

Hi,

For this application an LDO must have RΘJA thermal resistance of less than 132°C/W:

Pd = (Vin - Vout) * Iout = (24-5) * 0.05 = 0.95W

132°C/W * 0.95W = 125°C

Some AEC-Q100 LDOs that can support 24Vin, 5Vout and 50mA & <132°C/W thermal resistance are: TPS7B88-Q1, TPS7B81-Q1

Please let me know if you would like more suggestions or you need additional support or clarification.

BR,

Erin

0 PONNOJU NAGASHIRISHA over 2 years ago in reply to Erin Thibeault

Prodigy 40 points

Hi,

Can you suggest with same package?

Where input voltage is 24V & output voltage is 5V So that the power dissipation should not exceed the maximum limits.

Regards,

0 PONNOJU NAGASHIRISHA over 2 years ago in reply to Erin Thibeault

Prodigy 40 points

Hi,

Can you provide the maximum power dissipation of the suggested part no. TPS7B81-Q1

If you have any pre-defined value of power dissipation, please provide me so that for my design requirement the power dissipation is within the limits or not.

Thanks &Regards,

0 Erin Thibeault over 2 years ago in reply to PONNOJU NAGASHIRISHA

TI__Expert 6570 points

Hi,

Power dissipation can be approximated with (Vin -Vout ) * Iout

Since TPS7B81-Q1 has a maximum operating temperature of 150°C and thermal resistance R_ΘJA of 31.1°C/W, we can assume the maximum power dissipation the device can still operate at is:

((Vin -Vout ) * Iout)*31.1 = 150 or PD*31.1 = 150, PD = 4.8W

BR,

Erin

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TPS715-Q1: TPS71501QDCKRQ1