AN 745: Design Guidelines for DisplayPort Intel® FPGA IP Interface

ID 683623
Date 4/13/2020

1.1.2. AUX Channel

The DisplayPort AUX channel is a half-duplex, bidirectional channel running at 1 Mbps rate.
Figure 3. AUX Channel Differential PairThe AUX channel is a differential pair doubly-terminated with 50 ohm resistors and AC-coupled at both source and sink devices.

The 100-KΩ and 1-MΩ pull-up and pull-down resistors are placed between the connectors and AC-coupling capacitors. These resistors help detect any DisplayPort upstream devices, including a powered DisplayPort upstream device by a sink device.

Table 10.  AUX Channel Electrical SpecificationThe table shows the parameters of the DisplayPort AUX channel electrical specification.
Parameter Minimum Maximum Notes
AUX Direct Current (DC) Common Mode Voltage 0.0 V 2.0 V Common mode voltage is equal to Vbias_TX (or Vbias_RX)
AUX Peak-to-Peak Voltage 0.29 V 1.38 V Differential peak-to-peak voltage swing
AUX AC-Coupling Capacitor 75 nF 200 nF The AUX channel AC-coupling capacitors are placed on both the DisplayPort upstream and downstream devices.