Si8410/20/21
3. Application Information
3.1. Theory of Operation
The operation of an Si841x or Si842x channel is analogous to that of an opto coupler, except that an RF carrier is
modulated instead of light. This simple architecture provides a robust isolated data path and requires no special
considerations or initialization at startup. A simplified block diagram for a single Si8410 channel is shown in
Figure 11. A channel consists of an RF transmitter and receiver separated by a transformer.
Referring to the transmitter, input A modulates the carrier provided by an RF oscillator using on/off keying and
applies the resulting waveform to the primary of the transformer. The receiver contains a demodulator that decodes
the input state according to its RF energy content and applies the result to output B via the output driver.
TRANSMITTER
RF
OSCILLATOR
RECEIVER
MODULATOR
DEMODULATOR
A
B
Figure 11. Simplified Channel Diagram
3.2. Eye Diagram
Figure 12 illustrates an eye-diagram taken on an Si8410. The test used an Anritsu (MP1763C) Pulse Pattern
Generator for the data source. The output of the generator's clock and data from an Si8410 were captured on an
oscilloscope. The results illustrate that data integrity was maintained even at the high data rate of 150 Mbps. The
results also show that very low pulse width distortion and very little jitter were exhibited.
Figure 12. Eye Diagram
Preliminary Rev. 0.1
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SILICON [ SILICON ]
