OC-48 APPLICATION NOTE WITH AMAZON/S3059/S3056 AND SUMITOMO FIBER OPTIC
Terminations
The following is a list of terminations that need to be added for this particular design.
1. The 100 Ω line to line termination resistor should be as close to the termination points as possible.
2. The 200 Ω and 390 Ω pull down resistors should be as close to the sources as possible.
3. The high frequency traces should be designed as 50 Ω transmission lines with the termination as depicted in
Figure 2.
4. All the termination resistors should be placed at the end of the transmission line, and the power supply
decoupling should be placed as close as possible to the devices.
5. The CML and LVPECL (differential pairs) traces should have equal length, (allows both signals to arrive at the
destination at the same time) and be run in parallel and in close proximity of one another. This allows the same
noise to couple onto both of the lines and become common mode noise which is ignored by differential inputs.
Conclusion
The Sumitomo fiber optic transceiver, AMCC's S3059, S3056 and the AMCC AMAZON S4801 solution combine
to make a complete OC-48 Physical Media Dependent (PMD) layer for SONET/SDH data transfer.
Disclaimer
The circuit presented in this application note is based on data sheet information as well as standard implementa-
tion of termination schemes. It has not been built and tested in the lab environment.
4
March 26, 2001 / Revision 1.01
AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
