As can be seen in the images here, with minimal board space available on the SFP transceiver board, the diagnostics chip must be as small as possible. This chip must also give the performance levels required without having the flexibility of PCB design normally associated with high precision analog design. The ADuC7020 resides on the back of the PCB while the ADN2870 and ADN2892 lie on the front. In order to give JTAG debug options, a small SUR header is connected to the board. This can connect to an adaptor board with a standard 20 pin JTAG header.

