SPFMOR302 Avago Technologies, SPFMOR302 Datasheet - Page 6

• Manufacturer Part Number: SPFMOR302
• Description: Plastic Fiber Optic Receiver For Most
• Manufacturer: Avago Technologies

Top Layer with 180˚ version of the pigtail:
Bottom Layer (seen from the top side of the PCB):
Other items
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The shown circuit for the –3dB attenuation is just a proposal. Also any other circuit which can double the value of
Rext is permitted.
Due to the fact that the optical average level jumps if the power control signal (/-3dB) is toggled, LOCK/ coding –
errors can occur at the subsequent device for a short time. This is not very critical, since it occurs only in diagnosis
mode. After a time of 10ms, the device should lock again if the optical attenuation between the devices is not too
high.
The Rx and Tx signals can be measured by using standard probes (>1M/<10pF). However, if the signal quality is very
bad, and the LOCK signal of the MOST chip is flaky, connecting a passive probe to the Rx signal can cause the MOST
chip to lock better or worse to the signal. This is due to the capacitance of the analog probe which is usually in the
range of 8..12pF, which shifts the phase and PWD of the signal. In this case an active probe with a capacitance of less
than 1pF is recommended.
The reference test board which corresponds to the layout examples above, is available at the
Oasis SiliconSystems AG.
Bottom Layer: Bottom side / positions