DS160PR421: DS160PR421 bandwidth drop issue

Hi,

We use DS160PR421RUARl for the PCIe4.0 redriver, and the block diagram please refer to below:

Now, we test the PCIe communicate between the INTEL 12th Gen CPU( PCIe4.0 ) and RTX5070( PCIe2.0 ), the SMBus is not connect and the EQ0/ EQ1 connect to GND;

Now, the isue is DS160PR421RUAR will bandwidth loss(X8 drop to X4/X2...) if we use the block diagram circuit,

And there are no bandwidth loss if the CPU direct connect to RTX5070, however, DS160PR421RUAR connect to PCIe 4.0/ PCIe 3.0 board are also OK;

As we know, DS160PR421RUAR is support the PCIe 1.0 to PCIe 4.0, 

We consider to know, the PCIe1.0 and PCie2.0 have any diffenert designs from PCIe3.0 and PCIe 4.0, if yes, please help to advsie how to modify our design, thanks.

Hi Zhang,

Can you please share the schematic for the DS160PR12/21? Does this bandwidth loss occur every power-up, or only on some occasions?

Best regards,

Greg

Hi Gregory,

Gregory Kobyakov said:

Does this bandwidth loss occur every power-up, or only on some occasions

It is bandwidth loss occur every power-up when the devide is PCIe2.0(Customer has no PCIe1.0 board so this is no test data);

End customer can't provide the schematic for DS160PR12/21 becuase of the Non-Disclosure Agreement, so please advise if there are any different

design between PCIe1.0&2.0 with PCIe3.0 and PCIe4.0? We can promote customer to test based on your comment, thanks.

Hi Gregory,

The below is the updated block diagram from customer for your evaluate, please kindly review our request, this is urgent because it is happen on the end customer and we need to comfort customer complaints, thanks.

Hi Gregory,

End customer feedback us DS160PR421RUAR is ordered on 2021/2022, DS160PR421RUAR has the PCIe2.0 issue for the previous version,  I can't search the PCN for this updated, so please confirm if it is the main issue for this case, thanks.

Hi Zhang,

Could you please help provide the strapping information for the device if the schematic cannot be provided? Determining which modes the device is strapped to will help with the debug.

Best regards,

Greg

Hi Gregory,

Plesae refer to below feedback:

DS160PR421RUAR：

PIN 41， MODE， Pull-down 1K resistor

PIN 1， GAIN/SDA， NC

PIN 40，EQ0/ADDR， Pull-down 1K resistor

PIN 20，EQ1，  Pull-down  1K resistor

PIN 42，RX_DET/SCL，  NC

DS160PR412RUAR：

PIN 41， MODE， Pull-down 1K resistor

PIN 1， GAIN/SDA， NC

PIN 40，EQ0/ADDR， Pull-down 1K resistor

PIN 20，EQ1，  Pull-down  1K resistor

PIN 42，RX_DET/SCL，  NC

Hi Zhang,

Thanks for the update. I will check on this and will get back to you with comments as soon as possible.

Best regards,

Greg

Hi Gregory,

Thanks for our kindly support, and because this is the mass product and this issue happen on the site of the end customer, it may affect the subsequent orders, so please help to share us some solution to solve this issue, thanks.