Isolated digital inputs

Replace your optocoupler and simplify your PLC, grid or motor drive design

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Isolated digital inputs provide galvanic isolation between a sensor input, or other input type, and a logic output for a host controller interface. Compared to traditional optocoupler solutions, our isolated digital input devices provide a simple, low-power alternative with an accurate current limit. This alternative to optocouplers enables the design of compact and high-density I/O modules for PLC, AC and servo drives, and protection relay or substation automation grid applications.

Technical resources

Application note
Application note
How To Simplify Isolated 24-V PLC Digital Input Module Designs (Rev. B)
Are you designing a PLC digital input module? Learn how isolated digital inputs can simplify your design for IEC61131-2 Type 1, Type 2 and Type 3 standards.
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Technical article
Technical article
What are isolated digital inputs?
Find out how isolated digital inputs differ from digital isolators and why they are designed specifically for programmable logic control (PLC), motor control and grid applications.
Application note
Application note
How to Improve Speed and Reliability of Isolated Digital Inputs in Motor Drives
Learn how to improve the speed, noise immunity and reliability of isolated digital inputs in motor drive applications.
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Design & development resources

Reference design
Broken Wire Detection Using An Optical Switch Reference Design
This reference design shows a compact implementation of 16 isolated digital input channels using TI's ISO121x devices. The design is split into two groups of eight channels each. A broken wire detection can be executed using only one additional optical switch for each channel or two optical (...)
Reference design
Sub 1-W, 16-Channel, Isolated Digital Input Module Reference Design
This reference design shows a compact implementation of 16 isolated digital input channels using TI's ISO121x devices. The design works without an isolated supply and supports up to 100-kHz input signals (200-kbit) per channel. All 16 channels consume less than 1-W input power combined, which (...)
Reference design
96-Channel Bidirectional Digital Input Module Reference Design for PLC
This reference design is a compact implementation of 96 isolated digital input channels using the ISO1212, an isolated digital input receiver. This design shows the current limit feature of the ISO1212 device which has better thermal performance than traditional optocoupler solutions. This design (...)

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