SI8630 Datasheet, PDF (3/36 Pages) Silicon Laboratories – Low-Power Triple-Channel Digital Isolators

2. System Overview
Si8630/31/35 Data Sheet
System Overview
2.1 Theory of Operation
The operation of an Si863x channel is analogous to that of an opto coupler, except 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 start-up. A simplified
block diagram for a single Si863x channel is shown in the figure below.
Figure 2.1. Simplified Channel Diagram
A channel consists of an RF Transmitter and RF Receiver separated by a semiconductor-based isolation barrier. Referring to the trans-
mitter, input A modulates the carrier provided by an RF oscillator using on/off keying. The Receiver contains a demodulator that de-
codes the input state according to its RF energy content and applies the result to output B via the output driver. This RF on/off keying
scheme is superior to pulse code schemes as it provides best-in-class noise immunity, low power consumption, and improved immunity
to magnetic fields. See the following figure for more details.
Figure 2.2. Modulation Scheme
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