Specifications

PL 3120/PL 3150/PL 3170 Power Line Smart Transceiver Data Book 149
Surge Immunity of Example Circuits
The recommendations for the surge protection components that are included in the example circuits documented in this
chapter are based on testing performed on particular PCB layouts. The efficacy of the surge protection implemented in
each product containing the PL Smart Transceiver must always be verified empirically using the final product design
because factors such as PCB layout and packaging can influence the results as much as the choice of protection
components.
Table 4.13 lists the surge levels that the coupling circuits in this chapter can withstand without any damage to the
coupling circuit, the PL Smart Transceiver chip, or the PL Smart Transceiver interface circuitry. This criterion of “no
damage” is the one most commonly applied for surge testing. A simple and practical way to determine if a device has
been damaged after surge testing is to use the production test method described in Appendix D of this data book.
Checking the capacitance of C101 and C102 before and after a surge test is also recommended.
Each of the AC mains coupling circuits documented in this chapter was subjected to a sequence of surge events followed
by an Appendix D production test and capacitor test to verify that neither the coupling circuit, the Smart Transceiver chip
nor the associated discrete interface circuitry were damaged.
The surge waveform type and levels used to test each circuit are listed in Table 4.13. Tests in columns indicating “30
Surge Events” were tested with 5 events of positive polarity and 5 events of negative polarity at each phase angle of 0,
90 and 270 degrees (phase measured relative to the AC mains zero-cross rising edge). Tests in columns indicating “4
Surge Events” were tested with 2 events of negative polarity at 90 degrees and 2 events of positive polarity at 270
degrees. These phase and polarity settings were previously determined to provide the greatest level of stress to the most
sensitive components. Multi-phase coupling circuits were tested both with a single phase connected to the surge
generator and then again with all phases connected to the generator in parallel.
If the surge requirements for the product under test are different from those described in this section, then it is up to the
developer to perform testing in accordance with their own particular requirements. As mentioned above, the efficacy of
any surge protection plan must always be verified using samples of the final product because the results can vary with
circuit layouts.