SN74AVC4T774: Power dissipation

Allen yang

Expert 1045 points

Part Number: SN74AVC4T774

Hi Team,

Please provide the power dissipation data for the following products.

SN74AVC4T774RSVR

SN74AVC2T245RSWR

Thanks

28 days ago

0 Joshua Salinas 28 days ago

TI__Mastermind 27670 points

Hello Allen,

Please follow this FAQ to calculate maximum power dissipation.

[FAQ] Where do I find maximum power dissipation for a device?

Regards,

Josh

0 Allen yang 27 days ago in reply to Joshua Salinas

Expert 1045 points

Hi Joshua,

Is it possible to calculate the power dissipation using the operating voltage and current?

Taking the following circuit as an example, what is the approximate power dissipation during operation?

I want to back-calculate the Tj parameter.

0 Joshua Salinas 27 days ago in reply to Allen yang

TI__Mastermind 27670 points

Hello Allen,

We are looking at it and will respond soon.

Regards,

Josh

0 Allen yang 25 days ago in reply to Joshua Salinas

Expert 1045 points

Hi Joshua,

Any update on this? Thanks!

0 Joshua Salinas 25 days ago in reply to Allen yang

TI__Mastermind 27670 points

Hello Allen,

I'm a little behind on answering E2E, my apologies.

I will provide a response by EOD tomorrow.

Regards,

Josh

0 Allen yang 21 days ago in reply to Joshua Salinas

Expert 1045 points

Hi Joshua,

Any update on this? Thanks!

0 Jack Guan 20 days ago in reply to Allen yang

TI__Mastermind 44221 points

Hi Allen,

We are still looking into this and will provide a response soon.

Regards,

Jack

0 Allen yang 19 days ago in reply to Jack Guan

Expert 1045 points

Hi Jack,

Any update on this? Thanks!

0 Joshua Salinas 19 days ago in reply to Allen yang

TI__Mastermind 27670 points

Hello Allen,

I do apologize for the delay on this.

If you are trying to calculate the power dissipation during normal operation then we need to use the following:

Total Power = Static Power + Dynamic Power + Capacitive Load Power Consumption + Resistive Load Power Consumption.

Additional information can be found here: FAQ. Power consumption calculator can also be found there.

Regards,

Josh

0 Allen yang 14 days ago in reply to Joshua Salinas

Expert 1045 points

Hi Joshua,

What are the total power dissipation values for SN74AVC4T774RSVR and SN74AVC2T245RSWR?

Parameters as shown in the figure below

0 Joshua Salinas 13 days ago in reply to Allen yang

TI__Mastermind 27670 points

Hello Allen,

The total power dissipation that Nexperia uses is calculated from the package thermals and not operating voltage and current. The Ptot below is taken from 74AVC4T245 (Nexperia)

This goes back to the FAQ I shared in my first post.

[FAQ] Where do I find maximum power dissipation for a device?

Regard,

Josh

0 Allen yang 13 days ago in reply to Joshua Salinas

Expert 1045 points

Hi Joshua,

At an ambient temperature of 45 degrees Celsius

Temperature measured :

SN74AVC4T774RSVR package: QFN6, Tc max= 88.7°C

SN74AVC2T245RSWR package: UQFN10 , Tc max= 72.4°C

What is the approximate Tj value of the two ICs at this point?

What is the approximate value of Power Dissipation?

Thanks

0 Joshua Salinas 13 days ago in reply to Allen yang

TI__Mastermind 27670 points

Hello Allen,

TJ max would be 150C

Using the formula: P_max(W) = (T_J(max)(°C) - T_A(max)(°C)) / θ_JA(°C/W)

SN74AVC4T774RSVR: [(150°C - 125°C) / 139.2 C°/W] = 179mW

SN74AVC2T245RSWR: [(150°C - 125°C) / 227.4 C°/W] = 109mW

Regards,

Josh

0 Allen yang 12 days ago in reply to Joshua Salinas

Expert 1045 points

Hi Joshua,

You calculated Pmax (W), no problem.

At an ambient temperature of 45 degrees Celsius

Temperature measured :

SN74AVC4T774RSVR Tc max= 88.7°C

SN74AVC2T245RSWR Tc max= 72.4°C

Is the measured temperature normal, and how can it be verified?

What is the Tj under this condition?

0 Joshua Salinas 12 days ago in reply to Allen yang

TI__Mastermind 27670 points

Hello Allen,

Our team does not measure case temperature so we have no way to verify if the Tc value you shared is correct.

This is an equation I found online:

Case Temperature = Maximum junction temperature - (Junction-to-case thermal resistance X Power dissipation)

Regards,

Josh

0 Allen yang 11 days ago in reply to Joshua Salinas

Expert 1045 points

Hi Joshua,

Thanks

0 Joshua Salinas 11 days ago in reply to Allen yang

TI__Mastermind 27670 points

Hello Allen,

No problem.

Regards,

Josh

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SN74AVC4T774: Power dissipation