DS80PCI402SQE LPBK pin function

The loopback pin (LPBK) can be used to create a loopback path from INA - OUTB or INB - OUTA based on the input level shown in the table above.

There are EQA[1:0] and EQB[1:0] pins which control INA_n and INB_n inputs respectively.  Using the pins to control the equalization level gives 16 possible settings for each group of pins.

There are DEMA[1:0] and DEMB[1:0] pins which control OUTA_n and OUTB_n outputs respectively.  Using the pins to control the de-emphasis level gives 16 possible settings for each group of pins.

Additional control is possible using the ENSMB pin.  When using pin controls ENSMB = GND, if ENSMB = HIGH then additional control can be achieved on a per channel basis with SMBus registers.

Regards,

Lee