SI871X Datasheet, PDF (14/35 Pages) Silicon Laboratories – Industrial automation

Si871x/2x
2. Application Information
2.1. Theory of Operation
The Si871x/2x are pin-compatible, single-channel, drop-in replacements for popular optocouplers with data rates
up to 15 Mbps. The operation of an Si871x/2x 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 the Si871x/2x is shown in Figure 6.
Transmitter
RF
OSCILLATOR
Receiver
V_DD
Semiconductor-
A
LED
Emulator
MODULATOR
Based Isolation
Barrier
DEMODULATOR
~50
B
Gnd
Figure 6. Simplified Channel Diagram
14
Rev. 1.0