TUSB9261DEMO: Keeps resetting when connected to SATA SSD

Hi,

I am using the TUSB9261DEMO to connect a 2.5" 1TB SATA SSD (5V power) to my Windows laptop USB port (USB powered). I may use the TUSB9261 chip in a custom design I am working on, so I use the TUSB9261DEMO for evaluation.

I had no problem at first with a consumer-grade SSD (5V power), but then I switched to an industrial-grade SSD (as required by my application, also 5V power), which fails, either with a high-speed or superspeed USB cable. I tested this SSD with another USB-SATA converter and it works, so something is wrong with the TUSB9261DEMO.

When the industrial SSD is connected, the TUSB9261DEMO seems to be resetting periodically, about every second or so, appearing and disappearing in the Windows device manager. LEDs D3, D6 and D8 are briefly turned off at each reset cycle, then back on. The SSD is never mounted in Windows.

I probed the Vbus 5V supply and I see it drop to 4.2V during 2-3 ms, compared to 200us with the consumer SSD (see oscilloscope screenshots attached).

I probed all other supplies (3.3V, 1.8V, 1.1V) and they are all stable.

I probed the TPS2560 (U7) fault output and the TPS650061 (U4) RST output, both are always high, so no power fault it seems.

I probed the SATA_EN signal, it goes to 0V during 60ms at each reset, then back to 0.8V (see oscilloscope screenshots attached).

I probed the TX signal and there is data being emitted at each reset. Same for the SPI clock and data signals. I guess this is the TUSB9261 initializing.

Any idea what is happening and how to fix it ?

Thanks !