PCIe solution

Not sure that the intentions of designing the redrivers in the first place was to allow the use of bended/kinked cables to be connected to it. The prolonged and excessive use of bended cables may break eventually in the design and compromise the actual deliverables.

I can confirm with the designer of the part to see his own opinion and come back to you.Thanks.

Regards,

Edwin

In addition to my earlier response see below for some added info-

There is a maximum loss that can be handled using the redrivers. Obviously, with a bended cable there are more losses to be expected.

Please, what is the application, trace/cable length and the insertion loss that is anticipated to check if there is an option? Thanks.

Hi TTAEKYU,

This post is similar/same one that I have dealt with Terry H. over email thread- see below for some exchanges:

 Looking at the data that you sent on with reference to the FPCB cable – shows:

• A change in impedance discontinuities (and LG have measured 135 Ohms differential); as per PCIe spec. the PCB trace diff. impedance should be in the range 68 to 105 Ohms and I am not entirely sure that there is a strict requirement to have the cables/connectors etc. to match correctly to 68 to 105 Ohms.

• The B2B connector is showing 30mOhm – is this value insertion loss resistance for the B2B connectors?

1. Please ask that LG provide/measure the S11/S22, S12/S21 parameters of the FPCB using VNA and then convert the S – parameter values to a characteristic impedance.
2. If LG measured the impedance value that was provided and it was measured using TDR methodology, they could convert the measured impedance values to S-Parameter model.
3. Also confirm that the bent sections on the FPCB is measuring 135 Ohms, the unbent sections are 85 Ohms or the entire section of the cable is 135 Ohms due to the bending areas of the cable.

 The above are needed to gauge correlation of data, and to determine the reflections, insertion loss, return loss etc. to judge if ADI redrivers are suited for LG application design.

 Can you also provide a possible volume (small/large) estimate for the application, so that I can escalate to get quick designer support for LG request? I expect your quick feedback. Thanks so much.

In addition the HSPICE model was given to the customer to simulate the expected behaviour of the entire transmission line - still expecting feedback from the customer.

Regards,

edo