SN74LVC8T245: SN74LVC8T245PWR

RANGA SWAMY K

Part Number: SN74LVC8T245

Hi,

I couldn’t find the Maximum Junction Temperature detail of SN74LVC8T245PWR part in datasheet. Could you please help me to provide the Junction temperature value of SN74LVC8T245PWR part .

I want to know the maximum junction temperature the device can withstand. We have calculated the Junction Temp with PD, It came to 91 degrees. But operating temperature is -40C to +85C . Hence I need Max junction temperature rating parameter of SN74LVC8T245PWR part whichis missing in the datasheet. It would be a great help if you provide the Max junction temperature value the device can withstand at the earliest.

Regards

Ranga

over 7 years ago

0 ShreyasRao over 7 years ago

TI__Guru 61950 points

Ranga,

The max junction temp is 150C beyond which there could be reliability issues.
As long as the device is being operated within the recommended conditions, the abs max Tj is unlikely to be reached.

i have attached 2 app note which should help in this regard.

www.ti.com/.../scaa035b.pdf
www.ti.com/.../spra953c.pdf

0 RANGA SWAMY K over 7 years ago in reply to ShreyasRao

Intellectual 540 points

Hello Shreyas,

Many thanks for sharing the requested information. I would like to know the Recommended Junction temperature value instead of Absolute Max value for continuous operation of the device. Hence Could you please share the Recommended Junction temperature value of SN74LVC8T245PWR device.

Regards
Ranga

0 ShreyasRao over 7 years ago in reply to RANGA SWAMY K

TI__Guru 61950 points

Hi Ranga,

There is no recommended junction temperature in the datasheet spec.
The device is guaranteed to work at the rated ambient temperature, recommended operating voltage and current specs.

0 ShreyasRao over 7 years ago in reply to ShreyasRao

TI__Guru 61950 points

Ranga,

can you please elaborate on your calculation of Tj ? Did you measure the Pd ?

0 RANGA SWAMY K over 7 years ago in reply to ShreyasRao

Intellectual 540 points

Hi Shreyas,

Here is my TJ Calculations, Board Temperature (Ambient) is measured near to the unit. I need recommended TJ value to meet the thermal requirement of the device.

Board Temperature (Ambient) = 87.5 C
Power dissipation = 0.019 W
ThetaJA Package thermal impedance = 88 °C/W
Junction Temperature = TA + PD*ThetaJA
= 87.5 + 0.019 *88
= 89.172 C

Regards
Ranga

0 RANGA SWAMY K over 7 years ago in reply to RANGA SWAMY K

Intellectual 540 points

Hi Shreyas,

I mean recommended TJ valve for which device should operate as per specification.

Regards
Ranga

0 ShreyasRao over 7 years ago in reply to RANGA SWAMY K

TI__Guru 61950 points

Ranga,

This seems fine to me. There is always an increase of temperature as compared to the ambient temperature due to power dissipation. The logic devices do not have huge power consumption and hence the Tj is close to Ta (~15-20C)
As i said there is no recommended Tj value on the datasheet.

0 RANGA SWAMY K over 7 years ago in reply to ShreyasRao

Intellectual 540 points

Hi Shreyas,

Does it mean the device can operate within the spec with TJ in between 100C to 105C.

regards

Ranga

0 ShreyasRao over 7 years ago in reply to RANGA SWAMY K

TI__Guru 61950 points

Yes, will operate within the datasheet specs given that all the other input and output conditions are within the recommended specs.

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SN74LVC8T245: SN74LVC8T245PWR