TMDS181: TMDS181 power up timing requirement application question

Gabriel Xu

Part Number: TMDS181

Hi teams

My customer has several questions about TMDS181 application.

In datasheet section 6.9 there is a table that describes the power-up timing requirement:(Shown in below picture)

I wondering to know:

Are the VCC must power up after VDD power up and stable at least 200us?
What will happen if we power up the 3.3V VCC first and power up 1.2VCC after it?
I am confused by the mark "Vcc/Vdd" in the red rectangle. Are it indicates VCC or VDD ?

Thanks in advance.

0 David (ASIC) Liu over 6 years ago

Gabriel

VCC/VDD means VCC can be powered up before VDD or VDD can be powered up before VCC.

As long as the Td2 timing can be met, then Td1 is not critical.

Thanks

David

0 Gabriel Xu over 6 years ago in reply to David (ASIC) Liu

Hi David

You mean that no matter VCC or VDD which is come first , we only need to ensure the time delay between these two rail is longer than 200us?

I also have another question about temperature rise.

Customer test the top case temperature during thermal test and is up to 100C (40C ambient temperature)

I want to know:

How to leverage thermal information sheet parameter (datasheet section 6.4) to evaluate the junction temperature with measured top case temperature?

How to estimate the power loss in such situation?

Thanks in advance.

0 David (ASIC) Liu over 6 years ago in reply to Gabriel Xu

Gabriel

No, as long as OE goes high with minimum of 100us after VCC/VDD is stable, then there is no timing requirement between VCC and VDD.

For thermal calculation, please refer to this app note: http://www.ti.com/lit/an/spra953c/spra953c.pdf.

Thanks

David

0 David (ASIC) Liu over 6 years ago in reply to David (ASIC) Liu

Gabriel

Do you have any additional questions or can we close this thread?

Thanks

David

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