TPS1H100-Q1: max junction temperature calculation in function of driving time

Obinna Ezeilo

Part Number: TPS1H100-Q1

Hi team,

If my customer calculates the max junction temperature for their application with a constant current, they are above the maximum temperature. They would like to know how this can be calculated in function of the “driving” time?

Their specs are as follws:

Imax: 5A (no high side limitation)

Tmax: 50 or 100ms

Rdson_max: 166mOhm

Ta max: 85°C

Roja: 35 °C/W @100mm2 4layers

Tshutdown: 175°C

Worst case junction temperature

Do you have any suggestion?

Thanks for the help.

Obinna.

over 4 years ago

0 Timothy Logan over 4 years ago

TI__Mastermind 35405 points

Obinna,

The calculation you did is for steady state DC operation. For transient operation (such as the 50ms or 100ms) the RΘJA is dynamic and will result in less of a temperature increase.

The best way to calculate the junction temperature would be to use the thermal PSPICE model. For the TPS1H100-Q1 the PSPICE models have thermal modeling enabled:

https://www.ti.com/product/TPS1H100-Q1#design-development##design-tools-simulation

For a guide on how to measure the junction temperature with the PSPICE models please refer to the following application note:

https://www.ti.com/lit/pdf/slvaez0

0 Obinna Ezeilo over 4 years ago in reply to Timothy Logan

TI__Intellectual 2395 points

Hi Timothy,

Thanks for the response. The customer imported the model TPS1H100B-Q1 Unencrypted PSpice Transient Model Package (Rev. C) with some errors, but the simulation seems to work.

However, they would like to know what the copper area used for the model is and if it is possible to change it. Can you help with this information?

0 Timothy Logan over 4 years ago in reply to Obinna Ezeilo

TI__Mastermind 35405 points

Obinna,

The standard JEDEC 2s2p four layer layout was used with the copper coverage recommendations from the layout section in the datasheet. Were there any specific requirements for this application?

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TPS1H100-Q1: max junction temperature calculation in function of driving time