Bipolar Digital Field Inputs for PLCs and Industrial I/O Modules
The Si838x provides eight channels for 24 V digital field interface to either sinking or
sourcing inputs with integrated safety rated isolation. In combination with a few external
components, this provides compliance to IEC 61131-2 switch types 1, 2, or 3. The input
interface is based on Silicon Labs' ground-breaking CMOS based LED emulator technology
which enables the bipolar capability (sinking or sourcing inputs) with no VDD required
on the field side. The output interface to the controller allows for low power operation
with 2.25 V operation capability. These products utilize Silicon Laboratories' proprietary
silicon isolation technology, supporting up to 2.5 kVRMS withstand voltage. This
technology enables high CMTI (50 kV/μs), lower prop delays and skew, reduced variation
with temperature and age, and tighter part-to-part matching.