AN 713: DC Coupling in Stratix V Devices

ID 683790
Date 8/10/2015
Public

1. DC-Coupling in Stratix V Devices

AC-coupling consists of using a series capacitor with the transceiver link to filter out the DC component from a signal. DC-coupling allows both AC and DC signals to pass through a connection and does not require an additional series capacitor. Stratix® V GX and GS devices support DC-coupling on transmitter and receiver pins. Stratix V GT devices do not support DC-coupling on the ATT channels (28-Gbps channels). DC-coupling is supported on the GX channels of the Stratix V GT device.

One of the restrictions for DC-coupling Altera devices with non-Altera devices is that the transmitter and the receiver common mode voltages should match. When the transmitter and receiver common mode voltages are different, the two conflicting common mode voltages settle down to an intermediate common mode voltage level.

Figure 1. DC-Coupled Link