TUSB1064: Equalization settings vs power draw / thermal

Rob Helvestine1

Part Number: TUSB1064
Other Parts Discussed in Thread: TUSB1146,

Hello,

I'm using both the TUSB1064 and the TUSB1146 in a Type-C DisplayPort design. The products work great. However, I've noticed they get quite hot compared to everything else on the board when DisplayPort is active. At room temperature (28C), I ran DisplayPort for 20 minutes and the case temperatures of both devices were about 75C. Open enclosure, no convection, and no heat sink. I'm curious if TI has ways to reduce the quiescent power draw of these redrivers. Does lowering the EQ settings lower the quiescent power draw? Other than disabling them when not in use, how can I lower the case temperatures?

Thanks,

Rob

over 2 years ago

0 David (ASIC) Liu over 2 years ago

TI__Guru*** 139515 points

Rob

I am sorry for the late reply on your question. How do you connect the TUSB1064 thermal pad to the PCB ground plane?

I would also make sure there is sufficient solder paste coverage on the thermal pad, we recommend a minimal of 73% solder paste coverage.

Thanks
David

0 Rob Helvestine1 over 2 years ago in reply to David (ASIC) Liu

Intellectual 285 points

Hi David,

Below is a screenshot of the layout. Both the parts have the same via pattern. The vias are 0.2mm / 0.4mm. Layer 2 is ground. The entire thermal pad has solder paste on it.

0 David (ASIC) Liu over 2 years ago in reply to Rob Helvestine1

TI__Guru*** 139515 points

Rob

Your thermal pad design is following the TI's stencil pattern recommendation.

To answer your question, changing the EQ will not help with the TUSB1064 power consumption number or the thermal performance. The TUSB1064 power consumption comes from the number of lanes being disabled/enabled.

How big is your board? If you have a small board size, this would also lead to higher case temperature since you will have less thermal dissipation.

Thanks

David

0 Rob Helvestine1 over 2 years ago in reply to David (ASIC) Liu

Intellectual 285 points

OK thanks David. The board size is roughly 50mm x 55mm. It's a little surprising how hot these components get. Do you know if your customers use heat sinks for these parts?

+1 David (ASIC) Liu over 2 years ago in reply to Rob Helvestine1

TI__Guru*** 139515 points

Rob

I don't typically see customers using heatsink with the TUSB1064, but these designs are typically USB-C docks or monitors design which the board size is bigger or having more ground planes. So if we refer to the thermal metrics app note, https://www.ti.com/lit/an/spra953c/spra953c.pdf, part of the Junction-to-Ambient thermal resistance factor is PCB design.

If you also look at the TUSB1064 datasheet, enabling 4 DP lanes gives us the highest power consumption with typical of 660mW power consumption.

Thanks

David

0 Rob Helvestine1 over 2 years ago in reply to David (ASIC) Liu

Intellectual 285 points

Thanks David. That datasheet snippet is interesting and counter intuitive. I would think 2 lanes would draw less power than 4 lanes. I confirmed the temperature rise was the same with only 2 lanes of DP enabled.

Thanks for your help with this.

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TUSB1064: Equalization settings vs power draw / thermal