UC2825: UC2825 question

Masazumi Ishii

Part Number: UC2825

hello.

I have a question about UC2825.

①UC2825DW
About TJ of UC 2825 DW
Please let me know Tj (MAX).
The maximum value of Tj is not indicated in the data sheet.
Ta = max: 85℃
Power Dissipation = 1 W
θja = 50 ℃ / W
From this, I understand 125℃ is correct, is not it?
② Please tell me how to calculate the loss of UC2585DW.
Do you have this application note?

thank you.

over 6 years ago

0 Peter Meaney over 6 years ago

TI__Mastermind 31580 points

Hi

Let me check with the factory on the recommended Tj max. One method of checking the power dissipation of the controller is to measure the current into the Vcc pin by placing a series resistor of say 10R and measuring the voltage drop across it and multiplying the current by the Vcc voltage.

Regards

Peter

0 Peter Meaney over 6 years ago in reply to Peter Meaney

TI__Mastermind 31580 points

Hi

The device is electrically characterized to 85C, Tj = Ta. But for reliability, operation at 125C is ok but electrical parameters could be/will be outside of datasheet limits.

Regards

Peter

0 Masazumi Ishii over 6 years ago in reply to Peter Meaney

Genius 3945 points

Hello.

thank you for your answer.

Will you give me the following materials in addition?

1,Characteristic graph of Vcc vs Icc.

2,Characteristic graph of "Mounting board size vs temperature rise"

thank you.

0 Peter Meaney over 6 years ago in reply to Masazumi Ishii

TI__Mastermind 31580 points

Hi Maszasumi-san,

The Icc will depend on the switching frequency and the capacitive load presented by the Mosfet connected to the gate drive pin. This makes the variation of Icc with Vcc dependent on the specific application.

TI does not have comparative data for mounting board size versus temperature rise.

Regards

Peter

Power management

Power management forum

UC2825: UC2825 question