Some Challenge And Testing Of SFP+ Transceivers Compatible Cisco SFP+

SFP+ is the upgraded form of the SFP, 10G SFP+ transceiver are multi-purpose optical modules for 10Gbit/s data transmission applications at 850nm, 1310nm and 1550nm. The transceivers are ideally suited for datacom and storage space network (SAN/NAS) applications depending on the IEEE 802.3ae and Fibre Channel standards, Fiber Channel 10G, 8.5G, 4.25G, 2.125G, 1.0625G, 10GB SFP+ SR/SW/LR/ER, 1000 Base-SX Ethernet. The 10G SFP+ transceivers are fully compliant towards the SFP+ MSA and therefore are hot-swap.

While Cisco SFP+ minimises overall system cost, it puts new burdens on the PHY's design and gratifaction. The SFI between the host board and also the SFP+ module presents significant design and test challenges.

One obvious challenge may be the increased port density and the testing time required with 48 or more ports per rack. For instance, there are 15 measurements each for the host transmitter tests, and each of those measurements using manual methods can easily take from 3 to 5 minutes. What this means is an evaluation engineer is going to take more than one hour per port to accomplish the required tests, multiplied across the variety of ports.

Also is moving seamlessly from the compliance environment to some debug environment. If a measurement fails, how can the designer select which component is causing the failure and debug the problem to get to the basis cause? Such determinations are specially challenging due to the tight physical packaging small designs.

Yet another problem that a lot of designers face today concerns connectivity: how to get the signal out from the device under test (DUT) to a oscilloscope. Test fixtures are usually required but questions arise around whether or not the fixtures happen to be tested and validated from the specification.

The SFF-8431 SFP+ specification was written with the perspective that most design and test engineers use equivalent-time oscilloscopes. In fact, most designers would rather use real-time oscilloscopes since it assists them to get into debug mode more easily. Also with oscilloscopes supporting bandwidths of more than 30 GHz with fast sampling rates, rise serious amounts of bandwidth much less expensive of a constraint laptop or computer only agreed to be not too long ago. However, the process would be to interpret the specification in the context of a real-time oscilloscope in comparison to an equivalent-time model.

Also to organize for would be that the SFP+ specification calls out some measurements to become performed employing a PRBS31 signal. Some measurements (total jitter and eye-mask hit ratio) have PRBS31 being a recommended pattern. The utmost record length possible for acquisition with popular high-performance real-time oscilloscopes is 200 million samples. With a sampling rate of fifty Gsamples/s, the designer can acquire around 40 million unit intervals (UIs). At a sampling rate of 100 Gsamples/s, the instrument can acquire 20 million UIs. However, a PRBS31 pattern has more than 2 billion UIs. Hence, acquiring a complete pattern presents challenging.

Additionally, acquiring a record duration of 200 million data points demands huge processing power and time. One option would be to treat the PRBS31 waveform as a possible arbitrary waveform and get a modest record period of 2 million to Ten million UIs to recover the clock and compute the final results. This allows an excellent tradeoff between processing power and test-result accuracy.

Because it offers a great amount of detail about the health of your SFP+ design, test engineers must master the TWDPc measurement. TWDPC requires a special algorithm, which the SFP+ specification defines.

This test is defined as a pace from the deterministic dispersion penalty due to a particular transmitter with regards to the emulated multi-mode fibers and a well-characterized receiver. The fiber-optics concept may be extended to quantify the channel performance of high-speed copper links, also referred to as "10GSFP+Cu." Do you want to know more information about SFP+ transceivers or want to buy some fiber optic products.I think Fiberstore can help you.