Si87xx

12

Preliminary Rev. 0.5

2. Application Information

2.1. Theory of Operation

The Si87xx are pin-compatible, one-channel, drop-in replacements for popular optocouplers with data rates up to

15 Mbps. The operation of an Si87xx 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 Si87xx is shown in Figure 5.

Figure 5. Simplified Channel Diagram

RF

OSCILLATOR

MODULATOR

DEMODULATOR

A

B

Semiconductor-

Based Isolation

Barrier

Transmitter

Receiver

LED

Emulator

Output Stage

Open Collector