How to adjust the resistance of LS1046A's pin SD1_IMP_CAL_RX SD1_IMP_CAL_TX?

[125769962]

Hi

    I have two board,LS1046A is on mainboard, SFP+ cage is on carryboard. The SD1 signal  pass through a connector between two board.There are few bit errors when LS1046A receive or send data.Is the  connector must be 100 Ohm for differential pair? How to adjust the resistance of LS1046A's pin 'SD1_IMP_CAL_RX' and 'SD1_IMP_CAL_TX'。 

[June_Lu]

Please use SFP+ connecter fulfil MSA SPEC to connect the mainboard LS1046A and SFP+ transceiver.

The Serdes transmitter and reciever PCB traces are targeted at 100 Ω differential impedance with various little margin according to your PCB production.

The pins pin 'SD1_IMP_CAL_RX' and 'SD1_IMP_CAL_TX' must be terminated as specified - in opposite case normal SerDes operation will be impossible.

There is no additional customer-available details of the calibration pins operation. More details please see LS1046A datasheet page 20.

Please follow QCVS SerDes Tool User Guide  to generate Serdes user case configuration and Validation.